CALIFORNIA ENVIRONMENTAL PROTECTION AGENCY

AIR RESOURCES BOARD

STAFF REPORT:

INITIAL STATEMENT OF REASONS FOR PROPOSED RULEMAKING, PUBLIC

HEARING TO CONSIDER THE “LEV III” AMENDMENTS TO THE CALIFORNIA 

GREENHOUSE GAS AND CRITERIA POLLUTANT EXHAUST AND EVAPORATIVE 

EMISSION STANDARDS AND TEST PROCEDURES AND TO THE ON-BOARD 

DIAGNOSTIC SYSTEM REQUIREMENTS FOR PASSENGER CARS, LIGHT-DUTY 

TRUCKS, AND MEDIUM-DUTY VEHICLES, AND TO THE EVAPORATIVE EMISSION 

REQUIREMENTS FOR HEAVY-DUTY VEHICLES

 

This report has been reviewed by the staff of the California Air Resources Board and 

approved for publication. Approval does not signify that the contents necessarily reflect 

the views and policies of the Air Resources Board, nor does the mention of trade names 

or commercial products constitute endorsement or recommendation for use.

Date of Release: December 7, 2011

Scheduled for Consideration: January 26, 2012
Page ES-1

EXECUTIVE SUMMARY

Background

Despite significant progress in reducing smog-forming and particulate matter criteria 

emissions from the passenger vehicle fleet, California needs further reductions in order 

to meet State and federal ambient air quality standards. In addition, climate change 

continues to pose a serious threat to the economic well-being, public health, natural 

resources, and environment of California. To address the challenge presented by 

climate change, vehicle greenhouse gas (GHG) emissions must be drastically reduced 

to meet our goal of an 80% reduction from 1990 levels by 2050. 

California’s Light-Duty Vehicle Program

Criteria Emissions

In 1990, the Air Resources Board (ARB or Board) established the Low Emission Vehicle 

(LEV) program that contained the most stringent exhaust emission regulations ever for 

light-duty passenger cars and trucks. The regulations included three primary elements:

(1) tiers of increasingly stringent exhaust emission standards, (2) a fleet-average 

emission requirement for 1994-2003 that required manufacturers to phase-in a 

progressively cleaner mix of vehicles from year to year, and (3) a requirement that a 

specified percentage of passenger cars and lighter light-duty trucks be zero emission 

vehicles (ZEVs), vehicles with zero emissions of any pollutants.

In 1999, ARB adopted the second phase of the LEV program. These amendments, 

known as LEV II, set more stringent fleet average non-methane organic gas (NMOG) 

requirements for model years 2004-2010 for passenger cars and light-duty trucks and 

established a new more stringent super ultra-low emission vehicle (SULEV) standard. 

In addition, a partial zero-emission vehicle (PZEV) category was established for 

vehicles meeting the SULEV emission standard that also included extended 150,000-

mile durability, zero fuel evaporative emissions, and extended emission warranty 

requirements. PZEVs could be used to meet a portion of the zero-emission vehicle 

requirement. The amendments also expanded the light-duty truck category to include 

trucks and SUVs up to 8,500 lbs. gross vehicle weight rating (GVWR) and required 

these vehicles to meet the same emission standards as passenger cars, and extended 

full useful life from 100,000 miles to 120,000 miles. The LEV II amendments also 

established more stringent emission standards for medium-duty vehicles (MDVs) 

between 8,501-14,000 lbs. GVW. 

Greenhouse Gas Emissions

Recognizing the increasing threat of climate change to the well-being of California’s 

citizens and the environment, in 2002 the legislature adopted and the Governor signed 

AB 1493 (Chapter 200, Statutes 2002, Pavley). AB 1493 directed ARB to adopt the 

maximum feasible and cost-effective reductions in GHG emissions from light-duty 

vehicles. Vehicle GHG emissions included carbon dioxide (CO2), methane (CH4), and 

nitrous oxide (N2O) that are emitted from the tailpipe, as well as emissions of HFC134a, 
Page ES-2

the refrigerant currently used in most vehicle air conditioning systems. Table ES-1

below lists the global warming potential of these GHGs. 

Table ES-1. Numerical Estimates Of Global Warming Potentials Compared With CO2

(Kilograms Of Gas Per Kilogram Of CO2 -- Adapted From IPCC 2007c1

)

Climate 

Pollutants

Lifetime 

(years)

Global Warming Potential

20 years 100 years 500 years

 CO2 ~150 1 1 1

CH4 12 72 25 7.6

N2O 114 289 298 153

HFC134a 14 3830 1300 435

As directed by AB 1493, ARB adopted what is commonly referred to as the Pavley 

regulations, the first in the nation to require significant reductions of GHGs from motor 

vehicles. These regulations, covering the 2009-2016 and later model years, call for a 

17% overall reduction in climate change emissions from the light-duty fleet by 2020 and 

a 25% overall reduction by 2030. They also formed the foundation for the federal GHG 

program for light-duty vehicles for 2012-2016 model years.

After the Board adopted the Pavley regulations, the legislature adopted and the 

Governor signed AB 32, the California Global Warming Solutions Act (Chapter 488, 

Statutes 2006, Nuñez/Pavley). AB 32 charges ARB with the responsibility of monitoring 

and regulating GHG emissions in the State. AB 32 also directed ARB to prepare a 

Scoping Plan outlining the State’s strategy to achieve the maximum feasible and costeffective reductions in furtherance of reducing GHG emissions to 1990 levels by 2020. 

Measure T1 of the Scoping Plan anticipates an additional 3.8 million metric tons carbon 

dioxide equivalent (MMTCO2e) reduction by 2020 beyond the reductions from the 2009-

2016 AB 1493 standards.

In addition, in 2005, in order to mitigate the long-term impacts of climate change, the 

Governor issued Executive Order S-3-05. Among other actions, the Executive Order 

called for reducing GHG emissions to 80 percent below 1990 levels by 2050. This 

ambitious yet achievable reduction path and goal are considered necessary to stabilize 

the long-term climate.

ZEV Program

Although originally part of the LEV program, in 1999, in recognition of the increasing 

maturity of zero emission technologies and the critical role they can play in achieving 

California’s air quality goals, ARB established the ZEV program as a stand-alone one. 

Since then, the program has been modified several times to address the pace of 

development of zero emission technologies.

 1 IPCC 2007c: Working Group I: The Physical Science Basis, Chapter 2: Changes in Atmospheric Constituents and in Radiative 

Forcing, available at http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-chapter2.pdf
Page ES-3

At its March 2008 hearing, the Board directed staff to redesign the 2015 and later model 

year ZEV program by strengthening the requirement and focusing primarily on zero 

emission technologies – battery electric vehicles, hydrogen fuel cell vehicles, and plugin hybrid electric vehicles – in order to ensure that these low GHG technology vehicles 

transition from the demonstration phase to full commercialization in a reasonable 

timeframe. The resulting proposed amendments to the ZEV program are presented in a 

separate staff report, also part of this comprehensive vehicle rulemaking package, the 

Advanced Clean Cars program.

Advanced Clean Cars Program

Continuing its leadership role in the development of innovative and ground breaking 

emission control programs and to achieve California’s goals of meeting ambient air 

quality standards and reducing climate changing GHG emissions, ARB staff has 

developed the Advanced Clean Cars (ACC) program. The Advanced Clean Cars 

program combines the control of smog-causing pollutants and greenhouse gas 

emissions into a single coordinated package of requirements for model years 2015 

through 2025 and assures the development of environmentally superior cars that will 

continue to deliver the performance, utility, and safety vehicle owners have come to 

expect. The ZEV program will act as the focused technology-forcing piece of the 

Advanced Clean Cars program by requiring manufacturers to produce increasing 

numbers of pure ZEVs and plug-in hybrid electric vehicles in the 2018-2025 model 

years. In addition, the Advanced Clean Cars program includes amendments to the 

Clean Fuels Outlet regulation that will assure ultra-clean fuels such as hydrogen are 

available to meet vehicle demands brought on by these amendments to the ZEV 

program.

Beyond 2025, the dominant force for lowering emissions from vehicles in California will 

be climate change. In order to meet our 2050 GHG goal, the new vehicle feet will need 

to be primarily composed of advanced technology vehicles such as electric and fuel cell 

vehicles by 2035 in order to have nearly an entire new and used advanced technology 

fleet by 2050. Accordingly, the Advanced Clean Cars program coordinates the goals of 

the LEV, ZEV, and Clean Fuels Outlet programs in order to lay the foundation for the 

commercialization and support of these ultra-clean vehicles.

Figure ES-1 shows the cumulative on-road passenger vehicle fleet mix for one scenario 

developed by staff that achieves California’s 2050 GHG emission reduction goal. 

Importantly, ZEV sales must constitute nearly 100% of new vehicles in 2040 for ZEVs to 

constitute approximately 87% of the on-road fleet by 2050. 
Page ES-4

Figure ES-1. On Road Light-Duty Vehicle Scenario to Reach 2050 Goal

Criteria Emission Standards and New Certification Fuel Requirements

In order to achieve further criteria emission reductions from the passenger vehicle fleet, 

staff is proposing several amendments representing a significant strengthening of the 

LEV program. The major elements of the proposed LEV III program are:

• A reduction of fleet average emissions of new passenger cars (PCs), lightduty trucks (LDTs) and medium-duty passenger vehicles (MDPVs) to super 

ultra-low-emission vehicle (SULEV) levels by 2025;

• Replacement of separate NMOG and oxides of nitrogen (NOx) standards 

with combined NMOG plus NOx standards, which provides automobile 

manufacturers with additional flexibility in meeting the new stringent 

standards;

• An increase of full useful life durability requirements from 120,000 miles to 

150,000 miles, which guarantees vehicles operate longer at these extremely 

low emission levels;

• A backstop to assure continued production of super-ultra-low-emission 

vehicles after PZEVs as a category are moved from the Zero-Emission 

Vehicle program to the LEV program in 2018;

• More stringent particulate matter (PM) standards for light- and medium-duty 

vehicles, which will reduce the health effects and premature deaths

associated with these emissions;
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• Zero fuel evaporative emission standards for PCs and LDTs, and more 

stringent evaporative standards for medium- and heavy-duty vehicles 

(MDVs);

• More stringent supplemental federal test procedure (SFTP) standards for PC 

and LDTs, which reflect more aggressive real world driving and, for the first 

time, require MDVs to meet SFTP standards.

Table ES-2 below lists the proposed fleet average NMOG plus NOx requirements for 

PCs, LDTs, and MDPVs for model years 2015-2025.

Table ES-2. Fleet Average NMOG Plus NOx Exhaust Emission Requirements for LightDuty Vehicles (150,000 mile Durability Basis)

Model Year

Fleet Average NMOG plus NOx

(grams per mile)

All PCs; LDT1s LDT2s; MDPV

2015 0.100 0.119

2016 0.093 0.110

2017 0.086 0.101

2018 0.079 0.092

2019 0.072 0.083

2020 0.065 0.074

2021 0.058 0.065

2022 0.051 0.056

2023 0.044 0.047

2024 0.037 0.038

2025 0.030 0.030

Staff is also proposing three additional light-duty vehicle emission standards (ULEV70, 

ULEV50, and SULEV20) to which manufacturers may certify their vehicles when 

meeting the fleet average emission requirement. The numerical part of the standard 

category, such as 20 in SULEV20, refers to the emission standard, in thousandths of a 

gram per mile. Combined with an extended fleet average emission requirement phasein period, providing these additional emission standards will allow manufacturers to 

phase-in additional emission componentry across their fleet in a cost-effective manner.

Current California certification gasoline contains methyl tertiary butyl ether (MTBE) as 

an oxygenate, reflecting commercial gasoline sold prior to 2003 and as such does not 

represent gasoline currently sold in California, which does not contain MTBE. The 

current maximum ethanol content allowed in commercial gasoline is 10 percent by 

volume and is expected to remain at 10 percent for the foreseeable future. Accordingly, 

staff is proposing to change the certification fuel specifications to be more 

representative of current in-use fuel. Staff is also proposing that vehicles certify on a 

fuel that reflects the octane requirement that they are operated on in-use. Therefore, for 

vehicles that consumers must operate on premium fuel to maintain warranty coverage, 
Page ES-6

manufacturers may certify on premium grade fuel, while all others must certify on 

regular grade fuel.

Greenhouse Gas Emission Standards

 

The proposed GHG emission standards would reduce new passenger vehicle carbon

dioxide (CO2) emissions from their model year 2016 levels by approximately 34% by 

model year 2025, from about 251 to about 166 gCO2/mile, based on the projected mix 

of vehicles sold in California. The basic structure of the standards includes two 

categories – passenger cars and light-duty trucks – that are consistent with federal 

categories for light-duty vehicles. The standard targets would reduce car CO2

emissions by about 36% and truck CO2 emissions by about 32% from model year 2016 

through 2025. Figure ES-2 illustrates the basic target emission trends that are 

projected from the car and truck standards.

For the 2017-2025 model year standards, ARB proposes to use the United States 

Environmental Protection Agency (USEPA) approach and adopt separate standards for 

CO2, CH4, and N2O. 

Figure ES-2. Target Emission Reductions from GHG Standards

Table ES-3 shows the year-by-year new vehicle CO2 reductions that are projected as a 

result of the standards from cars, light-duty trucks, and combined light-duty vehicles. 

The projected result overall from 2016-2025 from these standards is to reduce car CO2

emissions by approximately 4.9%/year, reduce truck CO2 emissions by approximately 

4.1%/year, and reduce combined light-duty CO2 emissions by approximately 4.5%/year 

from 2016 through 2025. These CO2 emission reduction estimations are approximate 

because the required emission level to achieve compliance with the standards for each 

vehicle manufacturer depends on their ultimate sales mix of vehicles.
Page ES-7

Table ES-3. Projected Targets for Light-Duty Vehicle gCO2/mile Emission Rates

Model Car Truck Combined light-duty

year gCO2/mi Annual 

change gCO2/mi Annual change gCO2/mi Annual change

Baseline 2008 291 396 336

Previous

Rule Targets

2013 256 2.8% 330 2.8% 283 2.6%

2014 248 3.3% 321 2.8% 275 2.8%

2015 236 4.5% 306 4.5% 263 4.3%

2016 226 4.5% 292 4.5% 251 4.4%

Proposed

Rulemaking

Targets

2017 213 5.5% 290 0.7% 243 3.2%

2018 203 4.9% 280 3.5% 233 4.2%

2019 192 5.2% 273 2.8% 224 4.0%

2020 183 4.9% 264 3.0% 215 3.9%

2021 173 5.5% 245 7.5% 201 6.3%

2022 165 4.4% 233 4.9% 192 4.6%

2023 158 4.5% 221 4.9% 183 4.8%

2024 151 4.5% 210 5.0% 174 4.8%

2025 144 4.6% 200 4.9% 166 4.8%

Average change, (2016-2025) 4.9% 4.1% 4.5%

Change, 2008-2016 -23% -26% -25%

Change, 2016-2025 -36% -32% -34%

Change, 2008-2025 -51% -50% -51%

Notes: Car, truck, overall targets shown are based on projected sales of vehicles by footprint, category (ultimate gCO2/mile 

levels are determined by end-of-year sales); the original California GHG standards for model years 2009-2011 are based on 

a different two-category system (PC/LDT1 and LDT2) than the car and truck system of the 2012-2016 federal standards and 

proposed 2017-2025 standards; Difference of individual columns may not match due to rounding.

The already low CH4 and N2O standards will reflect the same stringency as the prior 

GHG standards. The net result is that, like the current 2009-2016 California GHG 

standards, the proposed 2017-2025 standards account for all major sources of vehicle 

GHG emissions, including upstream emissions associated with vehicle fuels. In 

addition, California is proposing to align its vehicle air conditioning system requirements 

with federal requirements.

Maximum Feasible and Cost-Effective Technologies

Vehicle manufacturers need sufficient lead-time to implement new technologies across 

their vehicle lines both from a feasibility and cost-effectiveness standpoint. 

Manufacturers will be resource challenged over the next 15 years as they strive to 

develop and implement technologies ranging from advanced gasoline and diesel 

engines to electric and fuel cell vehicles, while at the same time lowering criteria 

emissions of their combustion engines. The phase-in of the Advanced Clean Cars 

program requirements recognizes this by providing manufacturers with significant leadtime and considerable compliance flexibility.

Criteria Emissions

The technology for controlling vehicle emissions is well understood and manufacturers 

have a wide range of emission control technologies available to achieve SULEV 

emissions. Many of these technologies are already being used today on vehicles 
Page ES-8

meeting LEV II requirements and staff anticipates that with ongoing improvements to 

the effectiveness of these technologies, particularly catalyst technology, manufacturers 

will be able to meet the proposed LEV III requirements. For some vehicles, specifically 

the heavier vehicles with larger displacement engines, additional emission control 

componentry such as secondary air and hydrocarbon adsorbers may be required to 

achieve the proposed emission levels. 

Greenhouse Gas Emissions

The proposed GHG standards are also predicated on many existing and emerging 

technologies that increase engine and transmission efficiency, reduce vehicle energy 

loads, improve auxiliary and accessory efficiency, and that recognize increasingly 

electrified vehicle subsystems with hybrid and electric drivetrains. The previous 

rulemakings (i.e., California’s 2009-2016 and federal 2012-2016 standards) established 

an original technical basis for the proposed GHG standards. This rulemaking builds on 

this existing technical foundation with new technical data and understanding of evolving 

state-of-the-art engine, transmission, hybrid, and electric-drive technologies. As part of 

this effort, and without conceding any of California’s separate authority, staff has been 

working with the USEPA and the National Highway Transportation Safety Administration 

(NHTSA) since early last year to develop a unified national GHG program for motor 

vehicles beyond 2016 that will also meet California’s GHG goals. 

Environmental Impacts

 

Criteria Emissions

Table ES-4, Table ES-5, and Table ES-6 provide the emission benefits for calendar 

years 2023, 2025, and 2035 for reactive organic gas (ROG), oxides of nitrogen (NOx), 

and particulate matter (PM2.5) respectively. Emission benefits are nearly fully realized 

in the 2035-2040 timeframe when most vehicles operating in the fleet are expected to 

be compliant with the proposed Advanced Clean Car standards. By 2035 ROG 

statewide emissions would be reduced by an additional 34 percent, NOx emissions by 

an additional 37 percent, and PM2.5 emissions by 10 percent. 

Table ES-4. Statewide and Regional Emission Benefits of the Advanced Clean Car 

Program: Reactive Organic Gas (ROG)

Statewide ROG (tons/day)

Calendar

Year

Adjusted 

Baseline with 

Rebound

Proposed 

Regulation with 

Rebound

Benefits Percent 

Reduction

2023 189.6 182.9 6.6 3%

2025 175.5 164.4 11.1 6%

2035 141.1 93.6 47.4 34%
Page ES-9

Table ES-5. Statewide Emission Benefits of the Advanced Clean Car Program: Oxides of 

Nitrogen (NOx)

Statewide NOx (tons/day)

Calendar

Year

Adjusted 

Baseline with 

Rebound

Proposed 

Regulation 

with Rebound

Benefits Percent 

Reduction

2023 201.3 185.6 15.7 8%

2025 183.6 161.2 22.4 12%

2035 136.8 86.4 50.4 37%

Table ES-6. Statewide and Regional Emission Benefits of the Advanced Clean Car 

Program: Particulate Matter (PM2.5)

Statewide PM2.5 (tons/day)

Calendar

Year

Adjusted 

Baseline with 

Rebound

Proposed 

Regulation 

with Rebound

Benefits Percent 

Reduction

2023 26.7 26.0 0.6 2%

2025 27.2 26.3 0.9 3%

2035 29.7 26.8 2.9 10%

Staff used EMFAC 2011 to estimate the environmental benefits of the Advanced Clean 

Cars program. Staff’s analysis concluded that because the operating costs of vehicles 

meeting the GHG standards will decrease, vehicle use may increase. This effect is 

known as the rebound effect. When rebound rates were included in the inventory, there 

were negligibly (approximately one percent) fewer emission reductions compared to the 

substantial overall emission reductions expected from the Advanced Clean Car 

regulations package. 

Greenhouse Gas Emissions

The Advanced Clean Cars program would provide major reductions in greenhouse gas 

emissions. Table ES-7 shows the greenhouse gas emission benefits in 2020, 2025, 

2035, and 2050. By 2025, CO2 equivalent emissions would be reduced by almost 14

Million Metric Tons (MMT) per year, which is 12 percent from baseline levels. The 

reduction increases in 2035 to 32 MMT/Year, a 27 percent reduction from baseline 

levels. By 2050, the proposed regulation will reduce emissions by more than 42

MMT/Year, a reduction of 33 percent from baseline levels. Viewed cumulatively from 

2017 through 2050, the proposed Advanced Clean Cars regulation would reduce 

emissions by more than 870 MMT CO2 Equivalent. 
Page ES-10

Table ES-7. CO2-Equivalent (CO2e) Emission Benefits from Advanced Clean Car 

Regulations

Statewide CO2e Emissions (Million Metric Tons / Year)

Calendar

Year

Adjusted 

Baseline with 

Rebound

Proposed 

Regulation with 

Rebound

Benefits Percent 

Reduction

2020 111.2 108.1 3.1 3%

2025 109.9 96.3 13.7 12%

2035 114.8 83.2 31.5 27%

2050 131.0 88.3 42.7 33%

Cost Effectiveness

Criteria Emissions

Staff based its cost-effectiveness analysis on the projected increase in vehicle price 

assuming all new vehicles meet the SULEV emission standard in 2025. Based on the 

2008 fleet, staff determined that the average incremental retail costs for light-duty LEV 

III vehicles in 2025 are as shown in Table ES-8.

Table ES-8. Incremental vehicle price increase for 2025 criteria pollutant standard 

compliance

Vehicle

Category

Initial baseline 

certification

level

Engine size Average 

incremental 

price 

($/vehicle)

Average 

incremental 

price 

($/vehicle)

4-cyl 6-cyl 8-cyl

PC/LDT1

LEV $87 $142 $248 $130

ULEV $50 $83 $161 $68 $55

SULEV $0 $0 $0 $0

LDT2

LEV $87 $142 $248 $159

ULEV $50 $83 $161 $111 $117

SULEV $0 $0 $0 $0

The analysis concluded that the average cost-effectiveness of light-duty vehicles 

meeting the LEV III program exhaust requirements relative to the 2008 fleet is 

approximately $4.00 per pound of NMOG + NOx reduced. Staff also concluded that, 

since the proposed PM standards would be met by engine modifications during the 

normal course of engine development, no incremental increase in vehicle price would 

occur as a result. This cost estimate is likely conservative because the 2008 fleet 

average emission requirement is less stringent than the 2010 fleet average emission 

requirement when LEV II is fully phased-in. In addition, the 2025 fleet is projected to 

include a greater portion of downsized four and six cylinder engines that incur the lower 

costs to meet SULEV emissions. Stationary source controls can range up to $10 per 

pound of emissions reduced.
Page ES-11

Greenhouse Gas Emissions

Many of the technologies that reduce climate change emissions will also reduce the 

operating costs of light-duty vehicles. Estimates of the average reduction in operating 

cost of the new vehicles range from about 4 percent for MY2017 vehicles to over 25 

percent for MY2025 vehicles. Based on these expected operating cost reductions and 

projected gasoline prices, estimates of annual operating cost savings from 2015 through 

2030 are provided in Table ES-9. As shown, for every dollar spent, the regulation could 

save consumers about $3, for a cost-effectiveness in 2025 of $290 in savings per ton of 

CO2e reduction. These savings include the expenditures on electricity and hydrogen 

associated with operating the greater volume of ZEVs being proposed; in the absence 

of the proposed ZEV requirements, the savings and cost effectiveness would be 

greater. Overall, purchasers of new vehicles in 2017 and beyond would experience a 

significant reduction in their operating cost as a result of the proposed regulation.

 

Table ES-9. Estimates of Total Annual Value of New Vehicle Operating Cost Savings for 

Advanced Clean Cars (millions of 2009 Dollars)

Year

Cumulative 

Annualized 

Incremental 

Cost

Operating 

Cost Savings

Saving to 

Cost Ratio

2015 $1 $0 0.0

2016 $4 $0 0.0

2017 $33 $228 7.0

2018 $100 $487 4.9

2019 $225 $915 4.1

2020 $392 $1,438 3.7

2021 $609 $2,092 3.4

2022 $868 $2,918 3.4

2023 $1,163 $3,751 3.2

2024 $1,495 $4,671 3.1

2025 $1,827 $5,755 3.1

2026 $2,153 $6,846 3.2

2027 $2,475 $7,843 3.2

2028 $2,796 $8,803 3.1

2029 $3,114 $9,709 3.1

2030 $3,430 $10,630 3.1

Note: Operating cost savings are weighted to include costs for electricity 

and hydrogen for fueling zero-emission vehicles.

Economic Impacts

The greenhouse gas element of the Advanced Clean Cars program may impact several 

sectors of the economy. The steps that manufacturers will need to take to comply with 

the Advanced Clean Cars program are expected to result in price increases for new 

vehicles, while also leading to reduced operating costs, resulting in both positive and 
Page ES-12

negative impacts on California businesses and consumers. Any vehicle price increase 

will be borne by purchasers and may negatively affect businesses. However, the 

operating cost savings from the use of more efficient vehicles will positively impact 

consumers and most businesses. Based on staff’s analysis, the net effect of the 

program on the economy is expected to be small but positive. Tables ES-10, ES-11,

and ES-12 below show that overall, the benefits to California’s economy increase over 

time as cleaner, more efficient vehicles transition into the vehicle fleet.

Table ES-10. Economic Impacts of the Proposed Advanced Clean Cars (ACC) 

Regulations on the California Economy in Fiscal Year 2020 (2009 dollars)

California Economy Without ACC 

Regulations

With ACC 

Regulations Difference % ofTotal

Output (billions) $3,600 $3,602 $2 0.1

Personal Income (billions) $2,171 $2,172 $1 0.0

Employment (thousands) 17,913 17,919 6 0.0

Note: Difference of individual columns may not match due to rounding.

Table ES-11. Economic Impacts of the Proposed Advanced Clean Cars Regulations on 

the California Economy in Fiscal Year 2025 (2009 dollars)

California Economy Without ACC 

Regulations

With ACC 

Regulations Difference

% of

Total

Output (billion) $4,170 $4,178 $8 0.2

Personal Income (billion) $2,525 $2,528 $3 0.1

Employment (thousands) 18,966 18,987 21 0.1

Note: Difference of individual columns may not match due to rounding.

Table ES-12. Economic Impacts of the Proposed Advanced Clean Cars Regulations on 

the California Economy in Fiscal Year 2030 (2009 dollars)

California Economy Without ACC 

Regulations

With ACC 

Regulations Difference % ofTotal

Output (billions) $4,881 $4,895 $14 0.3

Personal Income (billions) $2,962 $2,968 $6 0.2

Employment (thousands) 20,179 20,216 37 0.2

Note: Difference of individual columns may not match due to rounding.

Impacts on Low Income and Minority Communities

ARB has made the consideration of environmental justice an integral part of its 

activities. Accordingly, staff evaluated the economic effects of the Advanced Clean 

Cars program on low-income households. For those households who purchase new 

vehicles, the economic effects of the regulations would be no different than on any other 

consumer. However, because residents in low-income communities tend to purchase 

used vehicles at a higher rate than residents in middle and high income communities, 
Page ES-13

staff evaluated the effects of the program on the used vehicle market and, more 

specifically, on low-income households that purchase used vehicles.

Staff concluded that, while the Advanced Clean Cars program will cause vehicle prices 

to increase, like other consumers, low-income consumers will see a significant reduction 

in vehicle operating costs. The fuel savings from more efficient used vehicles far 

outweigh the annualized cost of purchasing the vehicle (price increase spread over the 

years of ownership). Therefore, while purchase prices for used cars will increase by a 

small percentage of income, any increase in price will be more than offset by the 

operating cost savings. Tables ES-13 and ES-14 below show that whether purchasing 

new or 10-year-old used model year 2025 vehicles, the consumer will experience a net 

monthly savings from the program.

Table ES-13. Potential Impact on Monthly Loan Payment and Operating Cost Savings for 

New 2025 MY Vehicles (2009 dollars)

Description Advanced Clean 

cars Program

Average Increase in New Vehicle Price $1,900

Increase in Monthly Loan Payment $35

Net Lifetime Savings $4,000

Monthly Operating Cost Savings $48

Net Monthly Savings $12

Payback Period (Years) 2.9

 Note: Difference of individual columns may not match due to rounding.

Table ES-14. Potential Impact on Monthly Loan Payment and Operating Cost Savings for 

Used 2025 Vehicles (2009 dollars)

Description Advanced Clean 

Cars Program

Increase in Used 2025 MY Vehicle Price in 2035 $440

Increase in Monthly Loan Payment $14

Net Lifetime Savings $2,000

Monthly Operating Cost Savings $36

Net Monthly Savings $22

Payback Period (Years) 0.9

Public Process for LEV III Criteria and Greenhouse Gas Regulation Development

To support development of the Advanced Clean Cars program, beginning in March 

2010, ARB staff held five public workshops to engage stakeholders and obtain input on 

the proposed regulations. These stakeholders primarily included representatives from 

Original Equipment Manufacturers (OEMs) and vehicle component suppliers. 
Page ES-14

These workshops were held at ARB offices in El Monte. The announcements and 

materials for these workshops were posted on ARB’s website and distributed through a 

list serve that included over 1,500 recipients. Each workshop attracted just over 50 

attendees in person. Almost all of the meetings were either telecast, webcast or 

available by teleconference. The dates and materials presented at the workshops are 

available on ARB’s LEV III website 

at http://www.arb.ca.gov/msprog/levprog/leviii/leviii.htm.

ARB staff has also participated in dozens of individual meetings with vehicle 

manufacturers and vehicle component suppliers to discuss the fiscal and technical 

challenges presented by the proposed Advanced Clean Cars program. For the majority 

of the meetings concerning GHG technologies staff participated jointly with USEPA and 

NHTSA.

Vehicle Labeling Requirements 

Starting in the Spring of 2010, ARB staff began working with USEPA and NHTSA on a 

new national Fuel Economy Label. Such a label could be used in lieu of the California 

Environmental Performance label that California has required for over a decade. As a 

result, important California requirements are now addressed by the federal label. These 

included:

• Adding the following statement to the label: “Vehicle emissions are a 

significant cause of climate change and smog”

• Having a clear statement about upstream emissions and having a clear 

place to find this information on a regional basis.

• Including all cars in the rating system rather than segregating by size or 

class. 

Because of this successful collaboration California is able to harmonize with the federal 

labeling requirements. 

On-Board Diagnostics Amendments

Staff is also proposing changes to the On-Board Diagnostics II (OBD II) regulations. 

Staff was not scheduled to go to the Board this year to update the OBD II regulation; 

however, manufacturers recently approached ARB staff and requested regulation 

changes that they indicated were needed immediately in order to ensure compliance 

when they certify their 2013 model year vehicles. The proposed amendments to the 

OBD II regulation would include relaxation of a few requirements (e.g., delays to the 

required start dates) in recognition of delays in technology development. Additionally, 

manufacturers have requested that ARB staff propose clarifications to a few 

requirements in the current OBD II regulations, including those that address hybrid 

vehicles. ARB staff has already discussed the proposed amendments with hybrid 

manufacturers and have come to an agreement regarding these changes, which would 

consist of only minor software changes. 
Page ES-15

Other Considerations

Vehicle manufacturers have urged ARB to harmonize the requirements of LEV III with 

the federal Tier 3 program currently under development, which is expected to be 

finalized in mid-2012. While staff has worked with USEPA in an effort to align many of 

the requirements of the two programs, some elements of the proposed LEV III program 

are expected to remain more stringent than the federal program in order to address 

California’s unique air pollution problems. Nonetheless, staff believes that 

manufacturers will be able to certify their vehicles to both California and federal 

requirements when both programs are in effect.

Similarly, in response to an invitation by President Obama, ARB worked closely with 

USEPA and NHTSA on the development of national GHG and fuel economy 

requirements for 2017-2025. The footprint-indexed CO2 standard target lines for 2017-

2025 were examined jointly by the three agencies in order to address the agencies’ 

regulatory requirements regarding technical feasibility and cost-effectiveness. While the 

proposed CO2e standards for 2017-2025 reflect the same level of technical stringency 

for conventional vehicles staff anticipates will be adopted by USEPA in their final 

rulemaking, the GHG element of California’s Advanced Clean Cars program remains 

distinctive from the federal program because of its focus on California’s long-term GHG 

goals. By including specific ZEV requirements, the Advanced Clean Cars program lays 

the foundation to transform California’s light-duty fleet by ensuring that ultra clean 

vehicles meeting consumer expectations will be commercially available in the timeframe 

needed to achieve critical GHG reductions by 2050.

Staff Recommendation

ARB staff recommends that the Board adopt the LEV III regulation as proposed in

this Initial Statement of Reasons. The proposed regulation is intended to achieve

the maximum feasible and cost effective reduction of criteria and GHG emissions from 

new motor vehicles.
Page i

Table of Contents

I. INTRODUCTION.................................................................................................................. 1

A. OVERVIEW OF THE REGULATION ............................................................................... 1

B. ORGANIZATION OF THE REPORT................................................................................ 2

II. CALIFORNIA'S LOW-EMISSION VEHICLE CRITERIA POLLUTANT EMISSION 

REGULATIONS.................................................................................................................. 3

A. PROPOSED AMENDMENTS TO CALIFORNIA’S LOW-EMISSION VEHICLE EXHAUST 

EMISSION STANDARDS (LEV III)................................................................................. 3

1. BACKGROUND............................................................................................................ 3

2. SUMMARY OF PROPOSED AMENDMENTS.............................................................. 4

3. TECHNOLOGICAL FEASIBILITY OF PROPOSED STANDARDS ..............................29

4. COST ANALYSIS........................................................................................................37

5. OUTSTANDING ISSUES ............................................................................................42

6. REGULATORY ALTERNATIVES TO EXHAUST CRITERIA POLLUTANT EMISSION 

PROPOSAL.......................................................................................................................42

B. CALIFORNIA'S EVAPORATIVE EMISSION REGULATIONS.........................................43

1. BACKGROUND...........................................................................................................43

2. SUMMARY OF PROPOSED AMENDMENTS.............................................................46

3. TECHNOLOGICAL FEASIBILITY OF PROPOSED STANDARDS ..............................52

4. COST ANALYSIS........................................................................................................55

5. OUTSTANDING ISSUES ............................................................................................56

6. REGULATORY ALTERNATIVES TO EVAPORATIVE EMISSION PROPOSAL..........58

C. VEHICLE LABELING REQUIREMENTS.........................................................................59

1. BACKGROUND...........................................................................................................59

2. SUMMARY OF PROPOSED REGULATION ...............................................................61

3. COST ANALYSIS........................................................................................................61

D. MINOR AMENDMENTS TO THE ON-BOARD DIAGNOSTICS REGULATIONS............61

1. BACKGROUND...........................................................................................................61

2. SUMMARY OF PROPOSED AMENDMENTS.............................................................62

3. COST ANALYSIS........................................................................................................72

III. CALIFORNIA'S LIGHT-DUTY GREENHOUSE GAS REGULATIONS ...............................73

A. PROPOSED AMENDMENTS TO CALIFORNIA'S LIGHT-DUTY GREENHOUSE GAS 

EMISSION STANDARDS..............................................................................................73
Page ii

1. CLIMATE CHANGE OVERVIEW.................................................................................73

2. NATIONAL GREENHOUSE GAS PROGRAM DEVELOPMENT.................................97

3. SUMMARY OF PROPOSED REGULATION ...............................................................97

4. TECHNOLOGICAL FEASIBILITY OF PROPOSED STANDARDS ............................101

5. CLIMATE CHANGE EMISSION STANDARDS..........................................................126

IV. CERTIFICATION GASOLINE SPECIFICATIONS............................................................164

A. PROPOSED AMENDMENTS TO THE SPECIFICATIONS FOR CALIFORNIA 

CERTIFICATION GASOLINE......................................................................................164

1. BACKGROUND.........................................................................................................164

2. SUMMARY OF PROPOSED REGULATION .............................................................166

3. ALTERNATIVES TO THE PROPOSED E10 CERTIFICATION FUEL .......................171

V. EMISSIONS IMPACTS.....................................................................................................171

A. OVERVIEW OF EMISSIONS INVENTORY METHODS................................................171

B. ASSESSING BENEFITS OF THE PROPOSED REGULATIONS .................................173

C. ASSESSING THE IMPACT OF THE REBOUND EFFECT ...........................................173

D. EMISSION BENEFITS OF THE PROPOSED ADVANCED CLEAN CARS PROGRAM

....................................................................................................................................174

E. FUEL CYCLE EMISSIONS...........................................................................................178

F. HEALTH BENEFITS ASSOCIATED WITH REDUCTIONS IN PM AND NOx EMISSIONS 

FROM PASSENGER VEHICLES RESULTING FROM IMPLEMENTATION OF THE LEV 

III AND ZEV PROGRAMS ...........................................................................................185

1. OVERVIEW...............................................................................................................185

2. PREMATURE DEATH ESTIMATION METHODOLOGY ...........................................186

VI. ENVIRONMENTAL IMPACTS ANALYSIS .......................................................................190

VII. ECONOMIC IMPACTS ....................................................................................................191

A. LEGAL REQUIREMENTS ............................................................................................191

B. SUMMARY OF COMPLIANCE COST ESTIMATES .....................................................192

C. POTENTIAL IMPACTS ON BUSINESS CREATION, ELIMINATION, OR EXPANSION

....................................................................................................................................197

1. ENVIRONMENTAL-DYNAMIC REVENUE ANALYSIS MODEL (E-DRAM)...............198

2. AFFILIATED BUSINESSES ......................................................................................201

3. ECONOMIC IMPACTS OUTSIDE OF CALIFORNIA .................................................202

D. POTENTIAL IMPACT ON CALIFORNIA BUSINESS COMPETITIVENESS .................203

E. ANCILLARY BENEFITS................................................................................................203
Page iii

1. SOCIAL COST OF CARBON ....................................................................................203

2. ADDITIONAL ANCILLIARY BENEFITS.....................................................................207

F. POTENTIAL COSTS TO LOCAL AND STATE AGENCIES ..........................................208

G. POTENTIAL IMPACT ON MONTHLY LOAN PAYMENT AND OPERATING SAVINGS 

FOR NEW VEHICLES.................................................................................................209

H. JUSTIFICATION FOR ADOPTING REGULATIONS DIFFERENT FROM FEDERAL 

REGULATIONS...........................................................................................................210

I. CONCLUSION...............................................................................................................210

VIII. IMPACTS ON MINORITY AND LOW-INCOME COMMUNITIES .....................................211

A. ARB ENVIRONMENTAL JUSTICE POLICY.................................................................211

1. AB 1493 REQUIREMENTS.......................................................................................211

2. AB 32 REQUIREMENTS...........................................................................................212

3. OUTREACH TO MINORITY AND LOW-INCOME COMMUNITIES ...........................212

B. POTENTIAL ENVIRONMENTAL IMPACTS..................................................................213

C. POTENTIAL ECONOMIC IMPACTS.............................................................................213

1. POTENTIAL IMPACT ON A TYPICAL LOW-INCOME HOUSEHOLD .......................213

2. APPROACH ..............................................................................................................214

3. ASSUMPTIONS ........................................................................................................214

4. RESULTS..................................................................................................................215

5. ECONOMIC IMPACT ASSESSMENT ON AFFILIATED BUSINESSES IN LOWINCOME CITIES OF CALIFORNIA..................................................................................218

IX. OTHER CONSIDERATIONS ...........................................................................................220

A. CONSUMER RESPONSE EFFECTS ON EMISSIONS AND STATE ECONOMY ........220

1. BACKGROUND.........................................................................................................220

2. IMPACTS ON VEHICLE PRICES AND OPERATING COSTS ..................................221

3. IMPACTS ON VEHICLE SALES, FLEET SIZE, AND AVERAGE AGE......................224

4. IMPACTS ON CRITERIA EMISSIONS......................................................................227

B. ALTERNATIVE APPROACH TO ASSESSING CONSUMER RESPONSE...................229

C. ENERGY COST AND DEMAND FOR NEW VEHICLES...............................................231

D. MANUFACTURER RESPONSE TO INCREASED VEHICLE PRICES .........................234

E. EFFECT OF INCREASED FUEL PRICE ......................................................................235

F. SUMMARY AND CONCLUSIONS ................................................................................236

X. SUMMARY AND STAFF RECOMMENDATION...............................................................236

A. SUMMARY OF STAFF PROPOSAL.............................................................................236
Page iv

B. STAFF RECOMMENDATION.......................................................................................237

LIST OF ACRONYMS AND ABBREVIATIONS.......................................................................238

REFERENCES .......................................................................................................................242

APPENDICES.........................................................................................................................252
Page 1

I. INTRODUCTION

Vehicle manufacturers have made remarkable progress in the last two decades in 

achieving increasingly stringent emission requirements. Conventional vehicles meeting 

ARB’s most stringent emission standards have achieved emission levels that seemed 

impossible when the Low-Emission Vehicle (LEV) program was adopted in 1990. 

However, despite significant progress in reducing criteria emissions from the vehicle 

fleet, health-based State and federal ambient air quality standards continue to be 

exceeded in regions throughout California.

To achieve the 1997 ozone standard by the attainment date in 2023, NOx emissions in 

the greater Los Angeles region must be reduced by two thirds, even after considering all 

of the control measures in place today. In the San Joaquin Valley, the 2007 State 

Implementation Plan identified the need to reduce oxides of nitrogen emissions by 80 

tons per day in 2023 through the use of long-term and advanced technology 

strategies. To put this in context, this is equivalent to eliminating the NOx emissions 

from all on-road vehicles operating in these regions. Furthermore, California’s growing 

population and increasing use of motor vehicles will continue to exert upward pressure 

on statewide emissions.

In addition, climate change continues to pose a serious threat to California. Global 

warming is projected to have detrimental effects on some of California’s largest 

industries (including agriculture and tourism), increase the strain on electricity supplies, 

and contribute to unhealthy air. 2,3,4

 While significant reductions of vehicle greenhouse 

gas (GHG) emissions will be achieved by existing requirements of the LEV program, 

due to increasing vehicle population and vehicle miles traveled, continuing upward 

pressure beyond 2016 exists for GHG emissions. Furthermore, if we are to address the 

challenge presented by climate change, vehicle GHG emissions must be drastically 

reduced beyond current requirements to reach our goal of an 80% reduction from 1990 

levels by 2050. 

A. OVERVIEW OF THE REGULATION 

As the first in the nation to recognize the contribution of motor vehicles to environmental 

pollution, California has traditionally been a leader in the development of pioneering 

vehicle emission control programs. Continuing this tradition, and recognizing 

interrelated technologies reducing both criteria and GHG pollutants, the proposed LEV 

III regulations build upon the existing LEV program and address both criteria and GHG 

emissions as part of a whole program. The criteria element of LEV III calls for further 

reductions in vehicle emissions by requiring the average emissions of new vehicles to 

be equivalent to super-ultra-low emission (SULEV) levels by 2025. To place that in 

context, SULEV emission levels represent a reduction from uncontrolled vehicle 

 2 CRNA, 2009. California Natural Resources Agency. 2009. “2009 California Climate Adaptation Strategy” 3 UC Berkeley, 2008. University of California, Berkeley. November 2008. “California Climate Risk and Response” 4 ARB 2009a. California Air Resources Board. May 11, 2009 Update. “Climate Change Scoping Plan” 

http://www.arb.ca.gov/cc/scopingplan/document/scopingplandocument.htm
Page 2

emissions of greater than 99 percent. Phased-in from 2015-2025, the proposed criteria 

pollutant emission program provides significant flexibility to manufacturers by providing: 

1) an extended phase-in period for manufacturers to incorporate improved emission 

control systems across their vehicle lines: 2) an array of emission standards to which 

manufacturers may certify their vehicles, as long as their fleet average emissions meet 

the declining fleet average requirement: and 3) combined non-methane organic gas 

(NMOG) plus oxides of nitrogen (NOx) standards, which will enable manufacturers to 

more cost-effectively tailor their emission control systems.

The GHG element of LEV III essentially continues the LEV II “Pavley” standards ARB 

developed in 2003-2004 in response to AB 1493, and requires further reductions in 

vehicle GHG emissions beyond 2016. Phased in from 2017-2025, LEV III differs from 

the fleet average GHG requirement of the Pavley standards in that it establishes a set of 

footprint curves for each model year that sets target GHG emissions for each vehicle 

model depending on its footprint (the area described by wheelbase times the average 

track width of the vehicle). Similar to the criteria element of LEV III, manufacturers may 

produce models that emit above the footprint curve as long as their emissions are offset 

by models that emit below the footprint curve. In essence, the GHG requirements for 

LEV III are based on the sales weighted fleet average footprint of a manufacturer’s 

model lines and will vary between manufacturers depending on their vehicle model mix. 

Therefore, the GHG element of LEV III will mirror the structure of planned federal GHG 

requirements for motor vehicles. 

 

B. ORGANIZATION OF THE REPORT

The report begins with a description of exhaust criteria emission requirements, including 

the supplemental federal test procedure (SFTP), of the proposed LEV III program 

(section II.A.). This section also includes a discussion of the technical feasibility of the 

proposed standards and staff’s analysis of the compliance costs for manufacturers. 

Section II.B continues with a discussion of the proposed evaporative emission 

requirements and the technical feasibility and costs to achieve the requirements. 

Section II.C discusses changes to California’s Environmental Performance labeling 

requirements. Specifically discussed in this section is how staff worked with USEPA 

and NHTSA to ensure that the new federal Fuel Economy and Environmental Label 

meets California’s vehicle labeling requirements. California could thereby move to one 

national vehicle labeling program to avoid confusion among consumers trying to 

compare the environmental impacts of vehicles they are considering. Section III 

addresses the proposed greenhouse gas element of LEV III, starting with a discussion 

on climate change and its impact on California’s economic well-being, public health, 

natural resources, and environment. The section then describes the proposed GHG 

requirements for light-duty vehicles and the technology and costs to comply. Section IV 

discusses changes being proposed to the specifications for California certification fuel 

that are designed to reflect the composition of current and future in-use gasoline. 

Section V includes discussion of the emission benefits of the criteria and GHG elements 

of LEV III, as well as discussions on fuel cycle emissions, health effects, and energy 

cost and demand. Section VI summarizes the environmental analysis performed in 
Page 3

response to requirements of the California Environmental Quality Act. Section VII 

describes the economic impacts of the proposed regulations on California businesses, 

State and local agencies, and individual consumers, while section VIII focuses on the 

economic impact on minority and low-income communities. Section IX covers other 

considerations such as the effect of consumer response on emissions and the state 

economy, alternative approaches to assessing consumer response, effects on vehicle 

miles traveled, manufacturer response to increases in vehicle prices, and the effect of 

increased fuel prices.

II. CALIFORNIA'S LOW-EMISSION VEHICLE CRITERIA POLLUTANT EMISSION 

REGULATIONS

A. PROPOSED AMENDMENTS TO CALIFORNIA’S LOW-EMISSION VEHICLE 

EXHAUST EMISSION STANDARDS (LEV III)

1. BACKGROUND

In 1999, California adopted the second phase of the Low-Emission Vehicle Program 

(LEV). These amendments, known as LEV II, set more stringent fleet average nonmethane organic gas (NMOG) requirements for model years 2004-2010 for passenger 

cars and light-duty trucks and established a new more stringent super ultra-low 

emission vehicle (SULEV) standard. In addition, a partial zero-emission vehicle (PZEV) 

category was established for vehicles meeting the SULEV emission standard that also 

included extended 150,000-mile durability, zero fuel evaporative emissions, and 

extended emission warranty requirements. PZEVs could be used to meet a portion of 

the zero-emission vehicle requirement. The amendments also expanded the light-duty 

truck category to include trucks and SUVs up to 8,500 lbs. gross vehicle weight rating 

(GVWR) and required these vehicles to meet the same emission standards as 

passenger cars, and extended full useful life from 100,000 miles to 120,000 miles. The 

LEV II amendments also established more stringent emission standards for mediumduty vehicles (MDVs) between 8,501-14,000 lbs. GVW. Table II-A-1-1 below lists the 

vehicle classes affected by the LEV program.

Table II-A-1-1. LEV Vehicle Classes

Vehicle Class Weight Range5

Passenger cars All weights

Light-duty truck 1 (LDT1) 0-3750 lbs. LVW

Light-duty truck 2 (LDT2) 3751 lbs. LVW – 8,500 lbs GVWR

Medium-duty vehicle 8,501-10,000 lbs GVWR

10,001-14,000 lbs GVWR

 5 There are several classifications for vehicles based on weight. Curb weight is defined as the actual weight of the 

vehicle. Loaded vehicle weight (LVW) is defined as the curb weight plus 300 pounds. Gross vehicle weight rating 

(GVWR) is the maximum designed loaded weight of the vehicle; this means curb weight of the vehicle plus full 

payload. 
Page 4

2. SUMMARY OF PROPOSED AMENDMENTS

In order to achieve further emission reductions from the light- and medium-duty fleet, 

staff is proposing several amendments together that represent a significant 

strengthening of the LEV program. The proposed amendments would:

• Reduce fleet average emissions of new light-duty vehicles to super-ultra-lowemission vehicle (SULEV) levels by 2025, an approximate 75 percent 

reduction;

• Replace separate NMOG and oxides of nitrogen (NOx) standards with 

combined NMOG plus NOx standards;

• Establish additional emission standard categories to provide additional 

options for compliance;

• Eliminate intermediate useful life (50,000 miles) standards;

• Increase full useful life durability requirements from 120,000 miles to 150,000 

miles;

• Provide a backstop to help ensure continued production of super-ultra-lowemission vehicles after PZEVs migrate from the Zero-Emission Vehicle 

(ZEV) program to the LEV program in 2018. Without a backstop, beginning 

in 2018, manufacturers would not need to produce SULEVs until 2023 in 

order to meet the fleet average requirement;

• Establish more stringent emission requirements for medium-duty vehicles 

(MDV);

• Require all MDVs between 8,501-10,000 lbs, GVWR to certify on a chassis 

dynamometer, which would greatly enhance the ability to perform in-use 

compliance evaluation of these vehicles;

• Establish more stringent particulate matter (PM) standards for light- and 

medium-duty vehicles;

• Establish more stringent evaporative emission standards for light-, medium-,

and heavy-duty vehicles;

• Establish more stringent supplemental federal test procedure (SFTP, 

reflecting more aggressive driving) standards for light-duty vehicles and, for 

the first time, require medium-duty vehicles to meet SFTP standards;

• Allow pooled fleet average NMOG plus NOx emissions from California and 

the federal Clean Air Act Section 177 States that adopt the LEV III program;

and

• Revise the Non-Methane Organic Gas Test Procedures.

 
Page 5

2.1. Proposed Federal Test Procedure Exhaust Emission Requirements

A complete description of the regulatory amendments is contained in the appendices; a 

brief summary of each proposed amendment follows here.

2.1.1. Proposed NMOG Plus NOx SULEV Fleet Average Emission Requirement

As mentioned above, staff is proposing that the NMOG fleet average requirement be

replaced by a NMOG plus NOx fleet average requirement and be tightened down to 

SULEV emission levels by 2025. This represents a reduction from the current fleet 

average NMOG plus NOx emission requirement of approximately 75 percent. Table IIA-2-1 below lists the proposed fleet average requirement for passenger cars, light-duty 

trucks and medium-duty passenger vehicles (MDPV) for model years 2015-2025.

Table II-A-2-1. Fleet Average NMOG Plus NOx Exhaust Emission Requirements for LightDuty Vehicles (150,000 mile Durability Basis)

Model Year

Fleet Average NMOG plus NOx

(grams per mile)

All PCs; LDT1s LDT2s; MDPV

2015 0.100 0.119

2016 0.093 0.110

2017 0.086 0.101

2018 0.079 0.092

2019 0.072 0.083

2020 0.065 0.074

2021 0.058 0.065

2022 0.051 0.056

2023 0.044 0.047

2024 0.037 0.038

2025 0.030 0.030

Staff based the proposed SULEV level fleet average emission requirement in part on 

current certification data for vehicles meeting the PZEV emission standard. Vehicles 

meeting this emission standard represent a significant portion of the new light-duty 

vehicle fleet currently marketed in California, and certification in the passenger car (PC), 

light-duty truck 1 (LDT1), and light-duty truck 2 (LDT2) categories confirms feasibility. In 

addition, manufacturers have indicated that with the application of improved emission 

control systems they will be able to achieve this emission level across their light-duty 

fleet. To provide sufficient development time for manufacturers to incorporate improved 

emission control systems across their fleet, staff is proposing an extended eleven year 

phase-in from 2015-2025 to meet the SULEV fleet average requirement. This phase-in 

is also consistent with a similar phase-in of greenhouse gas requirements (2017-2025), 

also part of this rulemaking, and recognizes that the resources needed to 

simultaneously comply with multiple requirements are not unlimited. 
Page 6

2.1.2. Combined NMOG Plus NOx Emission Standards

Second, staff is proposing to combine the separate NMOG and NOx emission 

standards into a single NMOG plus NOx standard. Table II-A-2-2 below includes the 

proposed LEV III NMOG plus NOx emission standard categories for PCs and LDTs. 

Table II-A-2-2. Exhaust Federal Test Procedure Emission Standards for New 2015 and 

Subsequent Model Year LEV III Passenger Cars and Light-Duty Trucks

LEV III Exhaust Mass Emission Standards for New 2015 and Subsequent Model

Passenger Cars, Light-Duty Trucks, and Medium-Duty Passenger Vehicles

Vehicle Type

Durability 

Vehicle 

Basis (mi)

Vehicle 

Emission 

Category

NMOG + 

Oxides 

of 

Nitrogen

(g/mi)

Carbon 

Monoxide

(g/mi)

Formaldehyde

(mg/mi)

Particulates

(g/mi)

All PCs;

LDTs 8500 lbs. GVWR 

or less; and

MDPVs

Vehicles in this category 

are tested at their 

loaded vehicle weight

150,000

LEV160 0.160 3.4 4 0.003

ULEV125 0.125 1.7 4 0.003

ULEV70 0.070 1.7 4 0.003

ULEV50 0.050 1.7 4 0.003

SULEV30 0.030 1.0 4 0.003

SULEV20 0.020 1.0 4 0.003

Staff recognizes that achieving SULEV emission levels across the light-duty fleet 

presents a significant challenge to vehicle manufacturers and is therefore proposing 

several modifications designed to provide significant compliance flexibility without 

compromising needed emission reductions. First, as noted above, staff is proposing to 

replace separate NMOG and NOx emission standards with a combined NMOG plus 

NOx standard. These standards were combined in part because of the challenges

achieving SULEV emission levels for larger vehicles. Specifically, achieving the 10 

mg/mi SULEV NMOG standard is more problematic for vehicles equipped with larger 

displacement engines than achieving the 20 mg/mi SULEV NOx standard. So, by

providing an opportunity to slightly exceed the existing 10 mg/mi NMOG standard, a 

combined NMOG plus NOx standard would enable manufacturers to more costeffectively tailor their emission control systems while still achieving extremely low 

emission levels across their light-duty fleet. In contrast, though, smaller engines tend to 

be easier to control for NMOG emissions, but with more stringent GHG standards, these 

smaller engines will be under higher average loads, making NOx emission reductions 

comparatively more challenging. From an environmental perspective, staff continues to 

seek all technically feasible reductions of both NMOG and NOx, and the combined 

standard approach assures this is accomplished across all models and engine 

displacements very effectively.
Page 7

Staff is also proposing three additional light-duty vehicle emission standards (ULEV70, 

ULEV50, and SULEV20) to which manufacturers may certify their vehicles when 

meeting the fleet average emission requirement (as with LEV II, compliance is 

determined by averaging the discrete emission standard achieved for each model sold 

by the manufacturer, rather than the measured emissions from that model). Combined 

with an extended fleet average emission requirement phase-in period, providing these 

additional emission standards will allow manufacturers to phase-in additional emission 

componentry across their fleet in a more cost-effective manner.

Table II-A-2-3 below presents the phase-in requirements for passenger cars, light-duty 

trucks, and medium-duty passenger vehicles certifying to the LEV III FTP and SFTP 

standards.

Table II-A-2-3. LEV III Phase-in Requirements for Passenger Cars, Light-Duty Trucks, and 

Medium-Duty Passenger Vehicles

LEV III FTP and SFTP Phase-In

Year 2015 2016 2017 2018 2019

PC/LDT1 10% 20% 40% 70% 100%

LDT2/MDPV 10% 20% 40% 70% 100%

2.1.3. Proposed Interim In-Use Emission Standards for Passenger Cars, LightDuty Trucks, and Medium-Duty Passenger Vehicles

Staff is proposing that during the phase-in period manufacturers would be subject to 

less stringent in-use compliance standards (for the purpose of determining if a test 

group is in non-compliance and a possible recall is warranted) for the first two years

after a test group is subject to a new, more stringent emission standard. These interim 

in-use standards would apply only to vehicles certifying to ULEV70 and more stringent 

emission standards. This provision reduces a manufacturer’s risk of recall should 

emissions in-use turn out to be somewhat higher for a new technology than suggested 

by development and pre-sale certification testing. Vehicles certifying to PZEV 

requirements, including vehicles meeting the PZEV backstop provision (see section 

II.A.2.1.7 below), would not qualify for such interim in-use standards. Accordingly, the 

proposed interim standards will be applicable to those vehicles certifying to LEV III 

requirements prior to model year 2019. Table II-A-2-4 below lists the proposed 

intermediate in-use standards.
Page 8

Table II-A-2-4. Passenger Car, Light-Duty Truck, and Medium-Duty Passenger Vehicle

Interim Federal Test Procedure In-Use Emission Standards

Emission 

Standard

Interim FTP In-Use Emission Standards

NMOG+NOx (g/mi)

ULEV70 0.098

ULEV50 0.070

SULEV30 0.042

SULEV20 0.028

2.1.4. Proposed Elimination of Intermediate Useful Life Standards and Extension 

of Full Useful Life Standards to 150,000 Miles

Currently, with the exception of the SULEV emission standard, manufacturers are 

required to demonstrate compliance with an intermediate useful life standard at 50,000 

miles and a full useful life standard at 120,000 miles. Staff is proposing to eliminate the 

intermediate useful life emission standard for all emission standards and retain only the 

full useful life emission standard. Eliminating the intermediate useful life standards will 

align compliance requirements with the current SULEV requirement and federal Tier 2 

requirements for emission standards for Bin 5 and below for light-duty vehicles. This 

provision is being implemented in conjunction with a requirement extending full useful 

life standards from 120,000 miles to 150,000 miles. Extending full useful life durability 

from 120,000 miles to 150,000 miles would ensure more robust performance of 

emission control systems and, consequently, lower in-use emissions as vehicles age. 

Elimination of the intermediate useful life provision is not expected to impact vehicle inuse emission performance.

2.1.5. Proposed NMOG Plus NOx Highway Emission Standards

In order to control NOx emissions at speeds encountered on the highway test cycle, 

LEV II vehicles must certify to a highway NOx standard equal to 1.33 times the FTP 

NOx standard. Staff is proposing to carry over this requirement into LEV III. However, 

because the proposed LEV III emission standards are combined NMOG plus NOx 

standards, staff is proposing that NMOG plus NOx emissions on the highway emission 

test cycle not exceed the applicable NMOG plus NOx FTP emission standard. While no 

increase from FTP emissions is allowed under this approach, the combined NMOG plus 

NOx highway requirement provides manufacturers with considerable compliance 

flexibility in meeting this requirement, since current highway NMOG plus NOx emission 

certification values indicate significant compliance headroom exists for a combined 

highway emission standard.
Page 9

2.1.6. Non-Methane Hydrocarbon/Non-Methane Organic Gas Factor

In the current LEV II program, manufacturers are provided the option to apply a factor to 

their non-methane hydrocarbon (NMHC) emissions when reporting NMOG emissions to 

demonstrate compliance with the standards. The factor is based on current certification 

fuel and accounts for the oxygenated hydrocarbon components of the exhaust that are 

not measured by hydrocarbon instrumentation typically used in vehicle emission test 

cells. As described in section IV below, current California certification gasoline contains 

methyl tertiary butyl ether (MTBE) as an oxygenate, reflecting commercial gasoline sold 

prior to 2003 and as such does not represent gasoline currently sold in California. 

Therefore, staff is proposing to change gasoline certification fuel specifications to be 

more representative of current in-use commercial fuel that contains 10 percent ethanol 

as an oxygenate. Accordingly, staff is proposing a new factor for fuel containing 10 

percent ethanol that was derived from emission test results from vehicles operating on 

E10 from a test program contracted by the federal Department of Energy6 to support the 

federal waiver for E15. Based on the data from this study for E10 fuel specifically, a 

NMHC/NMOG factor of 1.11 was derived for emissions generated by a fuel with 10 

percent ethanol as an oxygenate. 

2.1.7. Proposed Passenger Car, Light-Duty Truck, and Medium-Duty Passenger 

Vehicle Particulate Matter Emission Standards

The LEV II standard for particulate matter (PM) for light-duty vehicles is 0.010 grams 

per mile. This standard was adopted primarily to provide an upper limit on PM 

emissions from light-duty vehicles since test data from typical gasoline vehicles at that 

time showed PM emission levels on the order of 0.001 to 0.002 grams per mile. Diesel 

vehicles meeting this standard were expected to employ particulate filters. This action 

also aligned California’s PM requirements with the federal Tier 2 program. 

Since then, California and federal emission requirements to reduce greenhouse gas 

emissions have fostered development of advanced internal combustion technology such 

as gasoline direct injection engines (GDI). Unlike conventional internal combustion 

engines using port fuel injection (PFI) where fuel is injected and mixed with air in the 

intake manifold prior to entering the combustion chamber, as the name implies, GDI 

engines inject fuel directly into the combustion chamber. Among other advantages, this 

provides a cooling effect on the air/fuel mixture, allowing for higher compression ratios 

and, therefore, improved engine efficiency and lower CO2 emissions. 

While test data from early versions of GDI engines have demonstrated compliance with 

the current 0.010 grams per mile PM emission standard, some vehicles have tested at 

measured PM emission levels of up to 0.008 grams per mile, significantly higher than 

comparable vehicles with PFI engines that typically test at PM levels at 0.001 gram per 

mile PM. However, later versions of GDI engines have tested at PM levels approaching 

 6 EPA Docket EPA-HQ-OAR-2009-0211
Page 10

0.001 grams per mile, indicating that significant improvements in PM emissions from 

GDI engines are achievable.

First generation GDI engines, called wall-guided GDI, used side mounted fuel injectors 

where the fuel spray pattern is formed by the piston crown and directed towards a 

center-mounted spark plug. In these systems, some fuel may impinge on the cylinder 

walls, valves, or other components, resulting in incomplete combustion and increased 

PM formation. In later generation wall-guided GDI systems, fuel impingement is 

minimized through use of higher pressure solenoid-controlled injectors that achieve a 

more finely atomized fuel charge, careful changes in combustion chamber geometry, 

piston shape, valve placement or other means. Perhaps even more effective, by again 

using center-mounted higher pressure solenoid-controlled fuel injectors, very low levels 

of PM emissions can be achieved more efficiently since the fuel charge would more 

easily avoid impinging on intake and exhaust valves or other combustion chamber 

components. This latter system is known as a spray-guided GDI system. Appendix P

provides a more detailed discussion of GDI technology and its impact on PM emissions. 

Accordingly, to encourage the continued development of GDI engines that emit PM at 

the same low levels as PFI engines, as listed in Table II.A.2.1.2 above, staff is 

proposing to reduce the PM standard from 0.010 grams per mile to 0.003 grams per 

mile for PCs and LDTs. Table II-A-2-5 below presents the phase-in requirements for 

this proposed 0.003 g/mi PM standard. The phase-in requirement represents the 

minimum percent of a manufacturer’s vehicle sales in each model year that must 

comply with the proposed 0.003 g/mi PM standard (whereas the remainder of the sales 

must comply with the 0.010 g/mi PM standard).

Table II-A-2-5. Particulate Matter Emission Standard Phase-In Requirements

Year 2017 2018 2019 2020 2021

PC/LDT1 10% 20% 40% 70% 100%

LDT2/MDPV 10% 20% 40% 70% 100%

Staff is also proposing an interim in-use compliance standard of 0.006 grams per mile 

during the phase-in period. Accordingly, vehicles certifying to the 0.003 gram per mile 

PM standard during model years 2017-2021, would be held to a 0.006 grams per mile 

PM standard for in-use compliance testing. Manufacturers would be required to 

emission test two test groups per year to demonstrate compliance with the proposed 

PM standards. These test groups would be selected by ARB during the model year precertification process. Manufacturers would also be required to perform PM emission 

testing on one high-mileage in-use vehicle per test group.

To order to further reduce the health impacts of PM, staff is proposing to reduce the PM 

standard to 0.001 grams per mile. This will ensure the continued development of low 

PM GDI engine technology and associated PM measurement procedures. The 

proposed phase-in for this standard is 25% in 2025, 50% in 2026, 75% in 2027, and 

100% in 2028 for both PC/LDT1 and LDT2. The phase-in requirement represents the 
Page 11

minimum percent of a manufacturer’s vehicle sales in each model year that must 

comply with the proposed 0.001 g/mi PM standard (whereas the remainder of the sales 

must comply with the 0.003 g/mi PM standard).

2.1.7.1. Reasoning for Removal of Earlier Staff Recommendation for New 

Particle Number and Black Carbon Standards for the LEV III PM Proposal

The downward trend in new vehicle tailpipe emissions presents additional challenges to 

the accurate and repeatable measurement of PM using the traditional gravimetric 

approach. Consequently, these emerging challenges are promoting interest in 

alternative measurement methods. At the November 2010 LEV III workshop, ARB 

sought comment on a proposal that would allow manufacturers to certify for compliance 

with the new proposed PM mass limits applicable to light- and medium-duty vehicles by 

using an optional and equivalent certification approach based on a new Solid Particle 

Number (SPN) standard. The proposed alternative would have required the 

measurement of SPN emissions using the instrumentation, protocols, and test 

procedures promulgated by the Particulate Measurement Programme (PMP). PMP 

recommendations for particle mass and number measurements were adopted into the 

Euro 5 and subsequent standards for cars. The PNP program is discussed in this 

staff’s report (Appendix P: Technical Support Document – Development of PM 

standards).

 

Originally, ARB staff established, in a discussion paper published in May 2010, that the 

intent of allowing for certification to an optional SPN standard was three-fold. First, the 

particle number limit proposal was a means to provide some compliance flexibility to 

vehicle manufacturers subject to LEV III who are also subject to the Euro standards. 

Broadly, flexibility was based on allowing for the use of a common set of test data for 

certification in Europe and California. Second, a SPN limit was seen as formal 

recognition of the emerging importance of ultrafine particle number emissions and as an 

update of the science underpinning California’s policies for clean cars. Finally, the 

proposed SPN limit allowed for a more practical, sensitive, and lower cost certification 

test procedure that would demonstrate good PM control. Recognition of the importance 

of the nexus between air and climate pollution also led to a preliminary recommendation 

for a new black carbon (BC) emission standard for future cars. 

New information and input provided to ARB staff suggests that there are still some 

important knowledge gaps in critical areas. Subsequent analysis and consideration of 

that information resulted in recognition that the proposal for SPN and BC standards was 

premature. Thus, at this point, staff is not proposing new SPN or BC limits. Additional 

discussion of knowledge gaps is provided below. However, staff is proposing more 

stringent PM mass limits and is recognizing the need for continuing PM method 

research and development efforts to help address the remaining data needs.
Page 12

The federal government is expected to make improvements to the gravimetric 

measurement for PM mass encompassed in 40 Code of Federal Regulations (CFR) 

Part 1065 for applicability to LDV emissions. The changes will improve the sensitivity, 

repeatability, and reproducibility of the technique and, hence, result in an accurate 

measurement of PM mass at the 0.003 g/mi level of emissions. ARB anticipates that 

the measurement of PM emissions at the 0.001 g/mi level will likely require further 

improvements. For this reason, the new limits are proposed to be phased in over many 

years in order to allow for, among other things, additional test method research and 

development. 

Alternative approaches to PM mass measurement will also be areas for additional 

testing and research. Today, there is evidence of a statistical correlation between PM 

mass, SPN, and BC. However, this evidence is very limited and not as definitive as the 

clear connection between higher temperatures and increased smog. At this time, ARB 

lacks data on the correlation of mass, number, and BC for various LDV technology 

types (i.e., PFI, GDI, GPF-equipped LDVs, etc.), for low and high mileage vehicles, or 

for vehicles with normal and abnormal oil consumption. This information is crucial 

before a conclusive link between PM mass, SPN, and BC can be established. 

However, the primary concern voiced by stakeholders with the proposed SPN 

measurement under PMP is its exclusion of particles in the sub-23 nm size range. 

Particles in this size range are known to be organic in nature and, hence, they are of 

high interest from a health protection perspective. In addition, ARB research suggests 

that exclusion of these particles does not appear to be necessary based on currently 

available instruments and laboratory practices. Additional research is underway in this 

area. Conversely, advantages to the alternative metrics for SPN and BC have also 

been observed. The measurement of BC appears to be an order of magnitude more 

sensitive than the measurement of PM mass. And the measurement of SPN appears to 

be an order of magnitude more sensitive than the measurement of BC. This implies 

that measurement of either SPN or BC could demonstrate PM mass control and that 

either method may be more than adequate for measuring the ultra-low PM emission 

levels expected from future vehicles. 

Black carbon emission reductions have great promise as part of climate change 

mitigation efforts. Since Black Carbon is a potent short-lived warming agent with 

emissions that can be considerably reduced using currently available technology, 

emission reductions can provide rapid short-term reductions in radiative forcing and 

hence slow global warming significantly in the short-term. Light-duty vehicles are 

currently a minor source of BC emissions compared to heavy-duty diesel engines. 

CARB anticipates that the stringency of the proposed amendments to the existing PM 

mass standard will result in reduced BC emissions that can yield significant local and 

regional climate and health benefit. 

ARB will continue work on PM mass measurement methods and also on alternative 

approaches to the conventional mass-based measurement, with a focus on the 1 

mg/mile standard for model year 2025. As discussed in Appendix P of this staff report, 

the most promising alternatives today include the consideration of potential 
Page 13

improvements to the European PMP approach so that it includes sub-23 nm particles as 

well as other emerging approaches based on the integration of the particle size 

distribution of the PM emissions or on the chemical reconstruction of PM mass profile. 

As we embark in these and other important undertakings that will set the stage for the 

future of laboratory measurements and vehicle emissions, ARB staff is committed to 

continue to share findings and hopes to receive cooperation and participation from all 

interested expert stakeholder groups. 

2.1.8. Proposed Backstop for Partial Zero-Emission Vehicle Production

Beginning in 2018, the Zero-Emission Vehicle (ZEV) program, also a part of the 

Advanced Clean Car rulemaking package, will undergo a major restructuring designed 

to focus on developing a commercial market for advanced electric drive vehicles such 

as battery electric, fuel cell and plug-in hybrid electric vehicles. Concurrently, partial 

zero-emission vehicles (PZEVs) and advanced technology partial zero-emission 

vehicles (AT-PZEVs) such as conventional hybrid electric vehicles (HEVs) and natural 

gas vehicles (NGVs), which are required to demonstrate emission durability for 150,000 

miles for SULEV and zero-fuel evaporative emissions, will transition from the ZEV 

program to the LEV program in 2018. In order to preserve the continued production of 

these very clean vehicles that a manufacturer would not need to produce in order to 

meet the proposed NMOG plus NOx fleet average requirement until it falls below 

ULEV50 levels in 2023, staff is proposing to require manufacturers to continue their 

production after they phase-out of the ZEV program. Therefore, staff is proposing that 

beginning in 2018, manufacturers be required to continue to certify a percentage of their 

new vehicle fleet meeting SULEV exhaust emissions and zero evaporative emissions 

for 150,000 miles equal to the average percentage of the sum of PZEVs and AT-PZEVs 

produced in model years 2012-2014. While these vehicles would continue to be 

required to meet SULEV exhaust and zero-fuel evaporative requirements, in 2018 and 

subsequent model years their movement from the ZEV to LEV program will mean 

manufacturers will no longer be required to offer an extended full life emission warranty. 

This reduction in warranty coverage is a result of a restriction in current California 

statute that limits the warranty period to 7 years or 70,000 miles, whichever occurs first.

2.1.9. Proposed Medium-Duty Vehicle Emission Standards

Medium-duty vehicles (MDVs) are defined as those with a gross vehicle weight rating 

(GVWR) between 8,501-14,000 lbs. Vehicles included in this category include the 

heavier pickup trucks such as the Ford F250 and F350, larger vans designed for 

carrying cargo such as the Ford Econoline 250 and 350, as well as delivery trucks with 

purpose built containers. Since these vehicles are typically used for work purposes and 

are subject to a more rigorous duty cycle, they are subject to less stringent emissions 

standards than trucks and minivans in the LDT2 category. While taking into account the 

more rigorous duty cycle, staff is proposing that overall emissions meet an equivalent 

MDV SULEV emission level for ninety percent of these vehicles. In 2022, 10 percent of 

MDVs may meet a less stringent ULEV standard in order to provide compliance margin 

for promising unanticipated greenhouse gas technologies. Table II-A-2-6 lists the 
Page 14

emission standards for MDVs. The MDV emission standards are to be phased-in from 

2016-2022. Tables II-A-2-7 and II-A-2-8 list the minimum sales-weighted phase-in 

requirements for the FTP and SFTP standards, the extended durability requirement, 

and the use of E10 certification fuel. Staff is also proposing to sunset, in model year 

2022, the least stringent LEV395 and LEV340 standards for MDVs between 8,501-

10,000 lbs. GVWR and the LEV630 and LEV570 standards for MDVs between 10,001-

14,000 lbs. GVWR.

Table II-A-2-6. Proposed FTP Exhaust Emission Standards for New 2016 and Subsequent 

Model Year LEV III Medium-Duty Vehicles

Proposed LEV III Exhaust Mass Emission Standards for New 2016 and Subsequent Model

Medium-Duty Trucks

Vehicle Type

Durability 

Vehicle 

Basis (mi)

Vehicle 

Emission 

Category

NMOG + 

Oxides of 

Nitrogen

(g/mi)

Carbon 

Monoxide

(g/mi

Formaldehyde

(mg/mi)

Particulates

(g/mi)

MDVs

8500 - 10,000 lbs. 

GVWR, excluding 

MDPVs

Vehicles in this category 

are tested at their 

adjusted loaded vehicle 

weight

150,000

LEV3951 0.395 6.4 6 0.008

ULEV3401 0.340 6.4 6 0.008

ULEV250 0.250 6.4 6 0.008

ULEV200 0.200 4.2 6 0.008

SULEV170 0.170 4.2 6 0.008

SULEV150 0.150 3.2 6 0.008

MDVs

10,001-14,000 lbs. 

GVWR

Vehicles in this category 

are tested at their 

adjusted loaded vehicle 

weight

150,000

LEV6301 0.630 7.3 6 0.010

ULEV5701 0.570 7.3 6 0.010

ULEV400 0.400 7.3 6 0.010

ULEV270 0.270 4.2 6 0.010

SULEV230 0.230 4.2 6 0.010

SULEV200 0.200 3.7 6 0.010 1 These certification levels would no longer be available from 2022 on
Page 15

Table II-A-2-7. Medium-Duty Vehicles 8,500-10,000 lbs. GVWR Federal Test Procedure 

Exhaust Emission Standards (Proposed)

Medium-Duty Vehicles 8,500-10,000 GVW (g/mi NMOG+NOx)

Year LEV ULEV340 ULEV250 ULEV200 SULEV170 SULEV150 Phase-in

0.395 0.340 0.250 0.200 0.170 0.150 150K, E10, SFTP

2016 20% 60% 20% 20%

2017 10% 50% 40% 40%

2018 40% 50% 10% 60%

2019 30% 40% 30% 70%

2020 20% 30% 50% 80%

2021 10% 20% 70% 90%

2022 10% 90% 100%

Table II-A-2-8. Medium-Duty Vehicle 10,001-14,000 lbs. GVWR Federal Test Procedure 

Exhaust Emission Standards (Proposed)

Medium-Duty Vehicles 10,001-14,000 GVW (g/mi NMOG+NOx)

Year LEV ULEV570 ULEV400 ULEV270 SULEV230 SULEV200 Phase-in

0.630 0.570 0.400 0.270 0.230 0.200 150K, E10, SFTP

2016 20% 60% 20% 20%

2017 10% 50% 40% 40%

2018 40% 50% 10% 60%

2019 30% 40% 30% 70%

2020 20% 30% 50% 80%

2021 10% 20% 70% 90%

2022 10% 90% 100%

2.1.10. Chassis-Certification of Medium-Duty Vehicles Between 8,500 - 10,000 

lbs. GVW 

Staff is also proposing that all MDVs in the 8,501-10,000 lbs. GVWR category be 

certified to chassis dynamometer-based emission standards. Currently, manufacturers 

may choose to certify incomplete gasoline and all diesel powered MDVs in this weight 

class to engine dynamometer emission standards. Staff is proposing to eliminate this 

option for several reasons. First, manufacturers are increasingly choosing to chassis 

certify their complete diesel MDVs in this category and have indicated that they will be 

expanding the number of chassis-certified vehicles in this weight class. Second, some 

manufacturers are already chassis certifying some of their incomplete MDVs. More 

importantly, requiring these vehicles to be certified to chassis dynamometer emission 

standards would facilitate in-use verification of their emissions by avoiding the need to 

remove the engine for in-use emission testing of vehicles certified to engine 

dynamometer emission standards. For these chassis-certified vehicles, manufacturers 

will need to include in the certification application the maximum recommended GVWR, 

curb weight, equivalent test weight, frontal area and applicable chassis dynamometer 
Page 16

settings.

2.1.11. Pooling Fleet Average NMOG plus NOx Emissions from California and 

Section 177 States 

Beginning in 2015, staff is proposing to provide an option to allow compliance with the 

fleet average NMOG plus NOx requirement be demonstrated using the pooled fleet 

average NMOG plus NOX emissions of new vehicles produced and delivered for sale in 

California and all states, including the District of Columbia if applicable, that adopt 

California’s emission requirements for light- and medium-duty vehicles. Manufacturers 

that choose this option would be required to report the number of vehicles produced and 

delivered for sale and the emission standards to which they are certified for each state, 

and the District of Columbia if applicable, that adopts California emission requirements. 

Including this provision provides additional compliance flexibility to vehicle 

manufacturers, particularly with respect to meeting a separate fleet average 

requirement in those states with limited new vehicle sales. While this represents a 

departure from past practice, staff believes that the emission impact of this provision 

within California and states that adopt California requirements will be minor due to the 

very low level of fleet emissions required by this program. Assigning credits and debits 

under this fleet emission-averaging scheme is discussed in the following section on 

credits and debits.

2.1.12. Credits and Debits

In the LEV II program, manufacturers may earn NMOG credits if they over-comply with 

the fleet average NMOG requirements and debits if they do not achieve it. Credits may 

be banked for future use to offset any NMOG debits or traded with other manufacturers. 

Under the current provisions, credits may be carried forward for three years, but are 

discounted beyond the first year and sunset in the fourth year. Debits must be offset 

the following model year. Staff is proposing to change the credit provisions to allow 

credits to be carried forward five years and carried back three years. This change will 

provide harmonization of LEV III emission credit provisions with federal emission credit 

provisions and provide an increased level of flexibility to manufacturers in meeting LEV 

III requirements. Staff does not anticipate an emission impact from this change due to 

very low fleet emission levels of the LEV III program. 

Most manufacturers are expected to have NMOG credits banked when LEV III starts in 

2015. Credits earned prior to 2015 would be discounted under the LEV II protocol and 

expire four years after they were accrued. In order to convert any LEV II NMOG credits 

carried forward to 2015 to NMOG plus NOx credits, staff is proposing a conversion 

factor of 3.0. This factor is derived by dividing the projected California fleet average for 

NMOG plus NOx for model year 2014 based on new vehicle sales of PC, LDT1, and 

LDT2 from EMFAC 2011 for 2014 by the NMOG fleet average requirement for 2014. A 

conversion factor of 3.0 is derived because the projected NMOG plus NOx fleet average 

in 2014 is approximately three times the NMOG fleet average. Similarly, any NMOG 

debits carried over to 2015 would be converted to NMOG plus NOx debits by multiplying 
Page 17

them by a factor of 3.0 and must be offset by any NMOG plus NOx credits earned in 

model years 2015 through 2018. 

As noted above, LEV III provides manufacturers with an option to pool their criteria 

emissions in California and the 177 states when determining compliance with program 

fleet average requirements. This means that a manufacturer may be over compliant in 

some states and under compliant in others but its compliance status is determined by 

the pooled emissions of vehicles produced and delivered for sale in California and the 

177 states. Note that manufacturers choosing this pooling option must still report their 

model year criteria emissions in each state. In addition, as noted above, the credit 

provisions are being changed to allow credits to be carried forward five years and 

carried back three years. In this case, a manufacturer would be non-compliant with the 

fleet average requirement when, it has no credits (either to carry forward or carry back 

or that can be purchased from other manufacturers) to offset any outstanding debits. 

Staff is proposing that when a manufacturer is deemed non-compliant with the pooled 

fleet average requirement, each state in which the manufacturer is determined to be 

non-compliant may take enforcement action based on the debits outstanding in that 

state. This is similar to the approach that California (and Section 177 States) took in 

allowing compliance with federal GHG standards in 2012-2016 to serve as compliance 

in California.

Staff is also proposing a 0.005 NMOG plus NOx gram per mile credit for vehicles that 

the manufacturer provides a 15 year/150,000 mile emission warranty. This credit would 

be applied to the emission values of the applicable test group when a manufacturer 

calculates its NMOG plus NOx fleet average value. 

2.1.13. Proposed FTP Phase-In Requirements to 150,000 Mile Full Useful life 

Emission Standards and E10 Certification Fuel 

As discussed in section IV, staff is proposing to require emission certification on two 

new California certification fuels. These fuels would have an ethanol content of 10 

percent and two octane ratings, 87 and 91 AKI, or “antiknock index.” AKI is defined as 

the average of ASTM research octane number (RON) and motor octane number 

(MON). Vehicles for which the manufacturer requires consumer operation on premium 

fuel to maintain warranty coverage may certify using California 91 AKI certification fuel. 

All other vehicles, including vehicles that the manufacturer suggests or recommends

operation on premium fuel, must certify using California 87 AKI fuel. The ethanol 

content and octane values of the new certification fuels are designed to assure that the 

fuel vehicles are certified on more accurately reflects the fuel they are operated on. 

Staff also proposes to retain the option to certify on federal Tier 3 certification fuel, 

which staff understands will be based on E15.

Accordingly, staff is proposing that manufacturers phase-in compliance to LEV III 

150,000 mile durability requirements, from 2015 through 2019, using the new California 

E10 certification fuels. To align with federal Tier 3 phase-in requirements, staff is 
Page 18

proposing that beginning in 2015 all vehicles certifying to emission standards below 

ULEV125 meet LEV III requirements to 150,000-mile durability using E10 certification 

fuel. Manufacturers would be required to certify all of their vehicles to 150,000-mile 

durability and E10 certification fuel in 2020. Because the declining fleet average 

requirement will require manufacturers to certify an increasing percentage of their 

vehicles to lower emission standards, staff believes this will assure an ordered 

progression of LEV III vehicles into the fleet, while providing flexibility to manufacturers 

in meeting LEV III requirements 

2.1.14. Early Phase-in Provision 

In order to encourage an earlier-than-required introduction of cleaner, more durable 

vehicles and to provide additional flexibility to manufacturers, staff is proposing an early 

phase-in option for vehicles certifying to ULEV70 and more stringent emissions 

standards. Because PZEVs already are required to achieve 150,000-mile durability per

the ZEV program, PZEVs would not be eligible for early phase-in credits. Under this 

option, the percentage of vehicles certifying in 2014 to LEV III NMOG plus NOx 

150,000-mile standards and SFTP requirements (certification using the new E10 

certification fuels would not be required) would be counted towards a manufacturer’s 

LEV III phase-in requirements. 

2.1.15. Small Volume Manufacturer Requirements

Independent vehicle manufacturers with a California three-year sales volume average of 

4,500 units per year or less of new PCs, LDTs, MDVs and heavy-duty vehicles and 

engines are currently defined as Small Volume Manufacturers. The manufacturers 

meeting this sales volume criterion (approximately a half dozen) were primarily those 

with very low volume sales (less than a thousand units per year) of high performance 

vehicles. In LEV II, compliance with the fleet average NMOG requirement for small 

volume manufacturers was deferred until 2007, the end of the phase-in period, 

Beginning in 2007, they were required to meet a fleet average requirement

approximately 53% less stringent than the fleet average requirement for larger 

manufacturers. The less stringent requirement for these manufacturers was adopted in 

recognition of their limited model lines with which to comply with fleet average 

requirements and limited investment and engineering resources to meet more stringent 

emission standards.

For LEV III, ARB is proposing to provide a similar relaxation in requirements to a subset 

of the Small Volume Manufacturers category that has a three-year average sales 

volume of less than 5,000 vehicles and engines nationwide. Staff estimates that a 

limited number of manufacturers (i.e., Lotus, McLaren, and Aston Martin) with limited 

vehicle model lines would meet the nationwide sales of 5,000 vehicles or less per year 

criterion. Staff believes that manufacturers that previously qualified for relaxed 

standards under the Small Volume Manufacturers category will continue to qualify for 

relaxed standards under this proposal. 
Page 19

Less stringent requirements for these very low volume manufacturers are justified for 

several reasons. First, these manufacturers are on the leading edge in developing 

vehicles using advanced vehicle design and lightweight materials. Their vehicles 

demonstrate in very real terms, the potential for innovative approaches to vehicle design 

and material use to achieve vehicle lightweighting without compromising safety 

(especially important for achieving very low GHG emissions). Second, as mentioned 

previously, they are at a competitive disadvantage (in terms of both investment and 

engineering resources) in that they must compete with full line manufacturers who are 

able to offset the emissions of their low volume high performance vehicles with higher 

volume, lower emission vehicles. Lastly, staff believes that periodic reviews of these 

manufacturers’ emission capability assures that they will continue to improve the 

emissions of their vehicles.

Accordingly, for qualifying vehicle manufacturers, staff is proposing that compliance with 

the LEV III requirements be deferred until the 2022 model year. Prior to 2022, small 

volume manufacturers with nationwide sales of 5,000 vehicles or less per year may 

petition ARB for relaxed emission standards. Consideration of relaxed standards would 

be based on a review of the manufacturers’ engineering and economic resources, 

criteria emissions of comparable vehicles certified by large volume manufacturers with a 

similar horsepower to weight ratios, documentation of good faith efforts to purchase 

credits from other manufacturers, and other relevant data. If determined appropriate, 

alternative emission standards would be granted for a period of up to 5 years and 

reconsidered at future 5-year intervals.

 

2.2. Proposed SFTP Exhaust Emission Standards

The California Supplemental Federal Test Procedure (SFTP) was developed to quantify 

and control motor vehicle emissions not accounted for by the Federal Test Procedure 

(FTP). Specifically, the SFTP captures so-called “off-cycle” emissions resulting from 

aggressive driving and air conditioner use. Off-cycle operating modes represent a 

significant portion of real-world driving and could result in significant emissions if 

vehicles are not properly calibrated. While the SFTP program is not intended to drive 

the installation of emission-control hardware, staff believes the emission standards are 

necessary to ensure that vehicular emissions are controlled through all modes of 

operation. 

In this rulemaking, staff is proposing to amend the SFTP program primarily in the 

following ways: 1) increase durability requirements; 2) expand applicability to mediumduty vehicles; 3) develop more stringent emission standards; and 4) add PM emission 

standards. These new proposed requirements would be implemented beginning with 

the 2015 model year and be phased in through the 2025 model year. 

This section presents an overview of staff’s specific proposal. Further detail is available 

in Appendix O, while the proposed test procedure text is included in Appendix C.
Page 20

2.2.1. Increasing Durability Requirements to Full Useful Life 

Staff is proposing a 150,000-mile durability requirement for SFTP emission standards to 

replace the 4,000-mile durability requirement currently in effect. The proposed durability 

requirement would be phased-in in accordance with the 150,000-mile durability phase-in 

proposed for the FTP.7 This proposed change would align the SFTP’s durability basis 

with that of the FTP and would ensure that control of off-cycle emissions is extended 

throughout the full useful life of on-road motor vehicles. 

When staff developed the existing 4,000-mile SFTP emission standards, it was unclear 

how aging of emission-control hardware would impact emissions over the SFTP driving 

cycles. However, data available today indicate that as vehicles age, increases in SFTP 

emissions are generally equivalent to increases in FTP emissions. Staff developed the 

150,000-mile SFTP emission standards based on such findings and believes it is 

appropriate to align the SFTP durability basis with that of the FTP. 

2.2.2. Applicability of SFTP Requirements

The proposed SFTP requirements would apply to 2015 and subsequent model year 

PCs, LDTs, and MDPVs, and 2016 and subsequent model year MDVs through 14,000 

pounds GVWR, including gasoline, diesel, alternative-fueled, and hybrid electric 

vehicles. MDVs and alternative-fueled vehicles were not previously subject to SFTP 

requirements because test data were not available to show they could comply with the 

emission standards and/or because manufacturers contended that such vehicles do not 

operate in the manner captured by the SFTP. Current driving patterns and emissions 

data, as presented in Appendix O, make it clear that it is appropriate to subject these 

vehicles to the proposed SFTP requirements. 

2.2.3. SFTP Passenger Car, Light-Duty Truck, and Medium-Duty Passenger 

Vehicle NMOG+NOx and Carbon Monoxide (CO) Emission Standards and PhaseIn

For PCs, LDTs, and MDPVs, staff is proposing two pathways to comply with the SFTP 

NMOG+NOx and CO emission standards. Option 1 would use stand-alone emission 

standards while Option 2 would use a composite emission standard approach with a 

fleet-averaging provision for NMOG+NOx. A fleet must commit to the option selected 

for the entire phase-in period. Under either approach, when a test group8 certifies to the 

150,000-mile durability requirements for LEV III FTP, it would be required to certify to 

150,000-mile SFTP emission standards as well. Capping CO emission standards would 

also apply for both Options 1 and 2 with the goal of preventing backsliding from current 

SFTP CO emission control levels. Staff believes that these options would provide 

planning flexibility without compromising the required emission reductions. 

 7 See section II.A.2.1.12 for further information. 8 See 40 CFR §86.1827-01 for the test group determination procedure.
Page 21

2.2.3.1. Stand-Alone Option (Option 1)

Table II-A-2-10 shows staff’s proposed Option 1 NMOG+NOx and CO exhaust emission 

standards for PCs, LDTs, and MDPVs. The phase-in of these emission standards 

would be tied directly to LEV III FTP certifications beginning with the 2015 model year. 

Specifically, a test group certifying to a particular LEV III FTP emission category would 

also be required to comply with the corresponding SFTP emission category (e.g., test 

groups certifying to LEV III FTP ULEV125, ULEV70, or ULEV50 would be required to 

meet the SFTP ULEV emission standards shown in Table II-A-2-10 below).

Table II-A-2-10. SFTP NMOG+NOx and CO Exhaust Emission Standards for New 2015 

and Subsequent Model Year LEVs, ULEVs, and SULEVs in the Passenger Car, Light-Duty 

Truck, and Medium-Duty Passenger Vehicle Classes, Option 11,2

US06 Test

(g/mi)

SC03 Test3

(g/mi)

Vehicle Type Mileage for 

Compliance

Vehicle 

Emission 

Category4

NMOG

+

NOx

Carbon 

Monoxide

NMOG

+

NOx

Carbon 

Monoxide

All PCs, LDTs 0-8,500 

lbs GVWR, and 

MDPVs 

Vehicles in this category 

are tested at their 

loaded vehicle weight 

(curb weight plus 300 

pounds).

150,000

LEV 0.140 9.6 0.100 3.2

ULEV 0.120 9.6 0.070 3.2

SULEV

Option A5 0.060 9.6 0.020 3.2

SULEV 0.050 9.6 0.020 3.2

1 Air to Fuel Ratio Requirement. See footnote 1, Table 2, Appendix O. 2 "Lean-On-Cruise" Calibration Strategies. See footnote 2, Table 2, Appendix O. 3 A/C-on Specific Calibrations. See footnote 4, Table 2, Appendix O. 4 Vehicle Emission Categories. Manufacturers must certify all vehicles, which are certifying to a LEV III FTP emission 

category on a 150,000-mile durability basis, to the emission standards of the equivalent, or a more stringent, SFTP 

emission category set forth in this table. All LEV III FTP LEVs certified to 150,000-mile durability shall comply with 

the 150,000-mile SFTP LEV standard, all LEV III FTP ULEVs certified to 150,000-mile durability shall comply with 

the 150,000-mile SFTP ULEV standard, and all LEV III FTP SULEVs certified to 150,000-mile durability shall 

comply with the 150,000-mile SFTP SULEV standard. 5 Optional SFTP SULEV Standard. MDPVs and LDTs 6,001-8,500 lbs. GVWR that are equipped with a particulate 

filter could certify to a higher NMOG+NOx emission standard for model years 2015 through 2020 in exchange for 

an extended 200,000-mile particulate filter emission warranty. See footnote 6, Table O-2, Appendix O. 

2.2.3.2. Composite Emission Standards with NMOG+NOx Fleet Averaging Option 

(Option 2)

The goal of the SFTP program is to ensure that software calibrations are optimized so 

that vehicles continue to effectively control exhaust emissions during off-cycle 

operations. It is not meant to be a driver of new hardware installation. Although staff 

had proposed Option 1 as the sole compliance option in their initial concept, after 
Page 22

additional analysis and discussions with stakeholders, staff determined that the Option 1 

emission standards would likely require diesel-fueled vehicles (which manufacturers 

have indicated they plan to produce to meet California and federal greenhouse gas and 

fuel efficiency mandates) to have additional costly emission-control hardware installed. 

Consequently, ARB staff is proposing a second option that would accommodate dieselfueled vehicles through less stringent emission standards and a fleet averaging 

provision. Staff expects that if a manufacturer has higher SFTP emissions from a diesel 

vehicle, it could make cleaner gasoline-fueled vehicles to partially offset the higher 

diesel emissions. Staff estimates that today’s fleet emits 7.5 tons per day (TPD) of 

NMOG+NOx during off-cycle driving conditions. This number would be reduced to 

approximately 2.9 TPD if all manufacturers certified to SFTP using Option 1 and 3.8 

TPD if all manufacturers certified using Option 2. Although Option 2 would not achieve 

the same level of NMOG+NOx emission reductions as Option 1, it is being proposed to 

be consistent with ARB’s original goal of developing an SFTP program that does not 

drive the installation of new emission-control hardware. While most OEMs have 

indicated to staff that they plan to choose Option 2 for SFTP compliance, ARB staff is 

still proposing Option 1 for OEMs that may not want to utilize fleet averaging, as well as 

for SVMs. SVMs would have a delayed phase-in into LEV III and thus would not have 

to certify to the more stringent SULEV emission category in Option 1 until after the last 

year of the phase-in, at which point they could simply elect to transition into Option 2. 

Under Option 2, for each test group, manufacturers would calculate composite emission 

values by weighting emission test results from the FTP, US06, and SC03 tests in g/mi, 

as shown by the following equation:

SFTP Composite Emission Value = 0.28 x US06 + 0.37 x SC03 + 0.35 x FTP [Eq. 1]

This is the same equation currently being used to determine compliance with federal 

SFTP emission standards. 

For CO, every test group certifying to SFTP would be required to meet the CO 

composite emission standard of 4.2 g/mi. However, for NMOG+NOx, manufacturers 

would use a sales-weighted fleet average to determine compliance. Specifically, 

manufacturers would certify test groups to “bins”, each with a bin-specific emission limit 

analogous to a family emission limit, or FEL. Manufacturers would then weight each bin 

based on sales volume to calculate their fleet-average emission value, as shown by the 

following equation:

∑ [(number of vehicles in the test group)i×(Composite Value of Bin)i] n

i=1

∑ (number of vehicles in the test group)i

n

i=1

where "n" =a manufacturer’s total number of certification bins in the PC, LDT 0-8,500 

pounds GVWR, and MDPV categories for a given model year;

[Eq. 2]
Page 23

 “number of vehicles in the test group” = the number of vehicles produced and 

delivered for sale in California in the certification test group;

 "Composite Emission Value of Bin" = the numerical value selected by the 

manufacturer for the bin that serves as the emission standard for the 

vehicles in the test group with respect to all testing, instead of the 

emission standard specified. Vehicles would certify to bins in increments 

of 0.010 g/mi. Beginning with the 2018 model year, vehicles would not be 

able to certify to bin values above a maximum of 0.180 g/mi. 

During the phase-in (shown in Table II-A-2-11 below), the fleet average would be 

calculated using a combination of carryover 4,000-mile SFTP composite emission 

values (adjusted to 120,000-miles and converted to NMOG+NOx) and new-certification 

150,000-mile SFTP composite emission values.

As presented in Table II-A-2-11, the composite emission standards would become more 

stringent each model year until the 2025 model year. Although this option would not be 

directly linked to FTP certification of LEV III vehicles, it would achieve fleet-wide SULEV 

level emission performance by the 2025 model year. 

 

Table II-A-2-11. SFTP NMOG+NOx and CO Composite Exhaust Emission Standards for

New 2015 and Subsequent Model Year Passenger Cars, Light-Duty Trucks, and MediumDuty Passenger Vehicles (Option 2)1,2,3,4

Model Year 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025

All PCs; LDTs 0-8,500 lbs 

GVWR; and MDPVs 8,501-

10,000 lbs GVWR

Vehicles in this category are 

tested at their loaded vehicle 

weight (curb weight plus 300 

pounds).

SFTP NMOG+NOx Sales-Weighted Fleet-Average Composite Exhaust Emission Standards 

(g/mi) 5,6

0.140 0.110 0.103 0.097 0.090 0.083 0.077 0.070 0.063 0.057 0.050

SFTP CO Composite Exhaust Emission Standard (g/mi)7

4.2 1 Air to Fuel Ratio Requirement. See footnote 1, Table 2, Appendix O. 2 “Lean-On-Cruise” Calibration Strategies. See footnote 2, Table 2, Appendix O. 3 A/C-on Specific Calibrations. See footnote 4, Table 2, Appendix O. 4 MDPV test groups would neither be subject to these emission standards nor be included in the NMOG+NOx fleet 

average until they certify to FTP emission standards at 150,000-mile durability. 5 For carry-over test groups not certified to LEV III FTP emission standards on a 150,000-mile durability basis, SFTP 

emission values shall be projected out to a 120,000-mile durability basis. Carry-over test groups may use the 

applicable deterioration factor from the FTP test. For test groups certified to a 150,000-mile durability basis on the 

FTP, the SFTP emission values shall be projected out to 150,000-miles for purposes of meeting the composite 

emission standards in this table. 6 Test groups would certify to bins in increments of 0.010 g/mi. Beginning with the 2018 model year, vehicles would 

not be able to certify to bin values above a maximum of 0.180 g/mi. 7 CO requirement. Unlike the NMOG+NOx composite emission standards, manufacturers would not be able to meet 

the proposed CO composite emission standard through fleet averaging. Each individual test group would be 

required to comply with the standard. Compliance would be determined using a composite emission value of the 

FTP, US06, and SC03 test results, as calculated using Equation 1. This CO emission standard would only apply to 

test groups certified to LEV III FTP emission standards at 150,000-mile durability. Test groups not subject to this 

CO emission standard would be required to meet the 4,000-mile CO emission standards of the existing SFTP 

program. The CO composite emission standard in this table does not apply to MDPVs until such 

vehicles are certified to LEV III FTP 150,000-mile durability requirements.
Page 24

2.2.3.2.1. Calculation of Fleet Average Total NMOG+NOx Credits or Debits

Option 2 would also allow manufacturers to generate credits or debits for each model 

year. A sales-weighted emission value lower than the composite emission standard 

would generate credits while a sales-weighted emission value greater than the 

composite emission standard would generate debits. For each model year, 

manufacturers would calculate their NMOG+NOx emission balance, as follows:

[(NMOG+NOx Composite Emission Standard) – (Manufacturer’s Sales-Weighted 

Fleet-Average Emission Value)] x (Total Number of Vehicles Produced and 

Delivered for Sale in California in the PC, LDT 0-8,500 pounds GVWR, and 

MDPV categories) [Eq. 3]

Total credits earned in a given model year would retain full value through the fifth model 

year after they are earned. At the beginning of the sixth model year, the total credits 

would have no value. Manufacturers would be required to offset all debits incurred in a 

specific model year within three model years, using available credits that either they 

have generated or have obtained via trading with other companies. Manufacturers 

would be allowed to trade credits with other manufacturers at any time.

2.2.4. Proposed SFTP NMOG+NOx and CO Emission Standards for Medium-Duty 

Vehicles 

Staff is proposing to extend SFTP applicability to MDVs starting with the 2016 model 

year. For NMOG+NOx and CO, MDVs certifying to SFTP standards would be required 

to comply with the applicable composite emission standards shown in Table II-A-2-12. 

To demonstrate compliance, manufacturers would calculate composite emission values 

for each test group by weighting emission test results from the FTP, US06 (or US06 

Bag 2 or UC, as appropriate), and SC03 tests using Equation 1, above. 
Page 25

Table II-A-2-12. SFTP NMOG+NOx and CO Composite Exhaust Emission Standards for 

New 2016 and Subsequent Model Year ULEVs and SULEVs in the Medium-Duty Vehicle 

Class1,2,3

SFTP Composite 

Standard4

(g/mi)

Vehicle Type5 Mileage for 

Compliance Hp/GVWR6 Test Cycle Vehicle Emission 

Category

NMOG + 

NOx

Carbon 

Monoxide

MDV 8,501-10,000 lbs 

GVWR 150,000

< 0.024 US06 Bag 2, 

SC03, FTP

ULEV 0.550 22.0

SULEV 0.350 12.0

> 0.024 Full US06, 

SC03, FTP

ULEV 0.800 22.0

SULEV 0.450 12.0

MDV 10,001-14,000 lbs 

GVWR

150,000 n/a

UC (LA92), ULEV 0.550 6.0

SC03, FTP SULEV 0.350 4.0

1 Air to Fuel Ratio Requirement. See footnote 1, Table 2, Appendix O. 2 “Lean-On-Cruise” Calibration Strategies. See footnote 2, Table 2, Appendix O. 3 A/C-on Specific Calibrations. See footnote 4, Table 2, Appendix O. 4 SFTP Composite Emission Value for MDVs 8,501-10,000 pounds GVWR = 0.28 x US06 (or US06 Bag 2, as 

appropriate) + 0.37 x SC03 + 0.35 x FTP, in g/mi. 

SFTP Composite Value for MDVs 10,001-14,000 pounds GVWR = 0.28 x UC + 0.37 x SC03 + 0.35 x FTP, in g/mi. 5 Vehicles in this category would be tested at their adjusted loaded vehicle weight (average of curb weight and 

GVWR) 6 If all vehicles in a test group have a power to weight ratio at or below a threshold of 0.024 would have the option to 

run the US06 Bag 2 in lieu of the full US06 cycle. The cutoff would be determined by using a ratio of the engine’s 

horsepower to the vehicle’s GVWR in pounds and would not include any horsepower contributed by electric motors 

in the case of hybrid electric or plug-in hybrid electric vehicles. Manufacturers would have the option to test to the 

full cycle regardless of the calculated ratio. In that case, manufacturers would be required to meet the 

requirements under the >0.024 provision. 

As can be seen in Table II-A-2-12, the different types of MDVs have different test 

cycles. This is necessary due to difficulties some of these heavier vehicles may have in 

following the accelerations present in the full US06 cycle. In general, MDVs in the 

8,501 through 10,000 pounds GVWR category would be subject to the US06 and SC03 

test procedures. However, some lower-powered MDVs in this category may have 

difficulties following the entire US06 trace. Specifically, the frequent and aggressive 

speed fluctuations of the US06 could cause overheating problems and be particularly 

troublesome for lower-powered MDVs. Therefore, staff is proposing to allow 

manufacturers of these vehicles to comply only with Bag 2 of the US06 cycle if the ratio 

of the engine’s horsepower to the vehicle’s GVWR in pounds is 0.024 or less. While the 

US06 Bag 2 cycle includes operation at the same maximum speed (80.3 mph) as the 

full US06 cycle, it does not include the frequent accelerations and decelerations found 

at the beginning and end of the full cycle. The proposed US06 Bag 2 emission 

standards have been adjusted to account for the change in testing cycle, but they are 

equivalent in stringency to the full US06 emission standards. The US06 Bag 2 test 

cycle is presented in Appendix O.
Page 26

Similarly, MDVs greater than 10,000 pounds GVWR may also have difficulty following 

the rapid accelerations contained in the US06 driving trace. Therefore, staff is 

proposing to have these vehicles use the California Unified Cycle (UC) instead. The UC 

is similar to the US06 test cycle, but with less aggressive speeds and acceleration. The 

proposed standards have been adjusted to reflect the different emission results that 

would be obtained under the UC as opposed to the US06 test cycle. The UC test cycle 

is presented in Appendix O. 

Manufacturers expressed some concern about costs associated with the SC03 test for 

MDVs. Because MDVs have significantly larger displacement engines and more power 

and torque than LDVs, the effect of using the air conditioner on emissions for this class 

is relatively modest. In addition, because manufacturers have noted that significant 

upgrades would be required for their environmental test cells to handle MDVs, staff 

proposes to allow an engineering evaluation in lieu of testing when certifying these 

vehicles to the proposed SC03 emission standards. Manufacturers electing to submit 

an engineering evaluation would use their FTP result instead of the SC03 result in 

Equation 1 when calculating compliance with the composite standard.

The proposed SFTP requirements for MDVs would be phased in beginning with the 

2016 model year. The phase-in would be based on the percentages of ULEVs and 

SULEVs certified on the FTP. Specifically, the percentage of MDVs required to certify 

to the SFTP SULEV emission standards would have to be equal to or greater than the 

percentage certified as a LEV III SULEV on the FTP. The same phase-in requirement 

would apply to ULEVs with the exception that instead of meeting or exceeding the LEV 

III FTP-certified ULEV percentage with SFTP ULEVs, a manufacturer could also certify 

additional SFTP SULEVs to meet or exceed this percentage. 

2.2.5. SFTP PM Emission Standards for PCs, LDTs, MDPVs, and Other MDVs

Staff is also proposing new SFTP PM Exhaust Emission Standards. Current GDI 

engines typically have higher PM emissions than port fuel injection engines. Because 

of this, PM exhaust levels, especially from gasoline-powered vehicles, have become a 

growing concern as the industry shifts from PFI engines towards GDI engines. All 

vehicles counted towards the 150,000-mile FTP PM emission standards phase-in in 

Table II-A-2-5 would comply with the SFTP PM Exhaust Emission Standards shown in 

Table II-A-2-13. The emission standards are primarily intended to prevent excessive oil 

consumption and fuel enrichment during aggressive driving and should not force 

installation of additional emission control technology. The PM emission standards are 

based on limited test data and will be reexamined as additional data become available. 

Because the data are limited, the proposed PM standards are not as stringent as the 

test data might suggest as feasible. This extra margin should ease manufacturer 

concerns about the relatively small test samples. The test data are presented and 

discussed in Appendix O.
Page 27

Table II-A-2-13. SFTP PM Exhaust Emission Standards for New 2017 and Subsequent 

Model Year Passenger Cars, Light-Duty Trucks, Medium-Duty Passenger Vehicles, and 

Other Medium-Duty Vehicles 

Vehicle Type Test Weight Mileage for 

Compliance Hp/GVWR1

Test Cycle2

PM

mg/mi

PCs 0-8,500 lbs GVWR; 

LDTs 0-6,000 lbs GVWR

Loaded vehicle 

weight 150,000 n/a US06 10.0

LDTs 6,001-8,500 lbs 

GVWR; MDPVs 

Loaded vehicle 

weight 150,0002 n/a US06 20.0

MDVs 8,501-10,000 lbs 

GVWR

Adjusted 

loaded vehicle 

weight

150,000

< 0.024 Composite 

US06 Bag 2 7.0

> 0.024 Composite 

US06 10.0

MDVs 10,001-14,000 lbs 

GVWR

Adjusted 

loaded vehicle 

weight

150,000 n/a Composite 

UC (LA92) 7.0

1 See Table II-A-2-3, footnote 5. 2 See Table II-A-2-3, footnote 4. 

2.2.6. Other Proposed SFTP Amendments

As part of the Advanced Clean Cars Program, staff is proposing to amend the 

certification gasoline specifications, as discussed in section IV, by removing MTBE as 

an obsolete specification, and requiring 10 percent ethanol by volume instead. This 

proposed modification would better align the specifications of certification test fuel with 

the properties of in-use fuel. For each test group, SFTP emission testing must be 

completed using the same fuel that is used to certify to FTP emission standards, as 

discussed in section II.A.2.1.12.

Staff is also proposing to regulate ozone precursors on the basis of NMOG+NOx 

instead of NMHC+NOx to harmonize with the FTP and federal requirements. The new 

NMOG+NOx emission standard basis better characterizes ozone formation potential 

because NMOG includes some ozone precursors that are not captured by the NMHC 

definition. Staff is proposing to use a factor of 1.03 to convert NMHC values to NMOG 

as discussed in Appendix O. 

Staff recently discovered that some manufacturers have been misinterpreting the test 

weight requirements of the existing SFTP program. Specifically, some manufacturers 

have been certifying LDTs9 6,001-8,500 lbs. GVWR to the SFTP emission standards at 

“loaded vehicle weight,” which is defined as curb weight plus 300 lbs. However, only 

PCs and LDTs 0-6,000 lbs. GVWR are supposed to be tested at loaded vehicle weight. 

 9 These vehicles are designated as MDVs 6,001-8,500 lbs. GVWR under the current SFTP program for MY2014 and 

prior vehicles.
Page 28

LDTs 6,001-8,500 lbs. GVWR are required to be tested at “average loaded vehicle 

weight,” which is defined as the curb weight plus half of its payload capacity. The 

average loaded vehicle weight is generally greater than the loaded vehicle weight, and 

reflects the greater payload capacity of these larger LDTs. Staff is proposing to amend 

the existing SFTP program in order to clarify its test weight requirements.

2.2.7. US06 and SC03 Emission Benefits/Cost Assessment

Compliance with the proposed SFTP regulation is expected to require better calibration 

and software upgrades. Staff does not believe any additional emission control 

hardware will be necessary to meet the proposed SFTP emission standards. Based on 

staff’s analyses, SFTP is expected to reduce NMOG+NOx emissions by 0.2 tons per 

day in 2025. These expected reductions would be driven entirely by US06 

requirements and primarily from MDV requirements. Although staff is not attributing any 

NMOG+NOx emission reductions to the proposed SC03 emission standards, staff 

believes they are still necessary to ensure proper calibration of vehicular air conditioning 

systems. Additionally, the CO emission standards for both US06 and SC03 are being 

proposed to prevent backsliding from current emission levels, and the SFTP PM 

emission standards are being proposed to prevent excessive oil consumption and fuel 

enrichment during aggressive driving. For more details regarding the emission 

reduction analysis, see Appendix O.

Most of the vehicle design and associated costs are covered in the LEV II and proposed 

LEV III FTP regulations. However, for MDVs and MDPVs, staff projects an additional 

testing cost of $10,000 per test group during the first year of SFTP phase-in due to the

additional testing required and testing facility upgrades that could be needed to certify 

these vehicles to the proposed SFTP requirements. Based on certification data from 

previous model years, there would be approximately 30 test groups in the affected

weight categories, thus yielding a $300,000 fleet-wide cost for SFTP. Based on the 

emission benefits noted above, the estimated cost-effectiveness of these regulations is 

approximately $0.20 per pound of NMOG+NOx reduced. 

2.3. Proposed Modifications to the Non-Methane Organic Gas Test Procedures

Staff is proposing several modifications to the “California Non-Methane Organic Gas 

Test Procedures,” as last amended July 30, 2002. This document describes the test 

methods and calculations that are to be used to determine vehicle NMOG mass 

emissions. Since the document was last amended, NMOG test methods used by ARB 

to determine NMOG mass emissions have changed. In addition, the calculations to 

determine NMOG emissions from vehicles operating on alternative fuels were based on 

M85 (fuel containing 85 percent methanol and 15 percent gasoline). This fuel is no 

longer available and has been replaced in the commercial fuel market by E85 (fuel 

containing 85 percent ethanol and 15 percent gasoline). Accordingly, the proposed 

modifications include updating the test methods and revising the calculation 

methodology to accommodate E85. Some modifications to align the mass emission 
Page 29

calculation with similar modifications USEPA has indicated that they will make are 

included.

2.4. Proposed Modifications to the “California Test Procedures for Evaluating 

Substitute Fuels and New Clean Fuels”

In order to facilitate the marketing of substitute and new clean fuels, in 1993, ARB 

developed a test procedure10 designed to assure that any proposed substitute or new 

clean fuel would not increase emissions from new and used vehicles. This test 

procedure required a specific mix of model year vehicles and the emission standards to 

which they were to be certified to be included in the demonstration test fleet. Since that 

time, vehicle technology and the emission standards to which they certify have changed 

significantly. As a result, the test fleet required in this test procedure is no longer 

representative of vehicles operating on the road today. Accordingly, staff is proposing a 

new test procedure that specifies a test fleet more representative of current new and 

used vehicles.

3. TECHNOLOGICAL FEASIBILITY OF PROPOSED STANDARDS

Emission control technology has under gone dramatic improvement over the last 

decade and is well understood by the industry. This section provides a brief discussion 

of the technology and recent advancements that have been made by both vehicle 

manufacturers and emission control component suppliers. 

3.1. Emission Control Technology

Close-Coupled and Underfloor Catalysts: Catalysts used on today’s vehicles 

typically use a combination of the precious metals rhodium, platinum and/or palladium 

as the catalytic material to control emissions of three major pollutant categories 

(hydrocarbons (HC), CO, and NOx). While significant advancements have been made 

in improving the performance of three-way catalytic converters, further improvements in 

catalyst design and materials are on-going. One example of this is the development of 

a “zoned” catalyst where precious metal distribution is optimized for maximum 

conversion efficiency. This same study demonstrated that optimizing the distribution 

and composition of the oxygen storage materials in the catalyst and improving the 

precious metal support structure resulted in a reduction of rhodium sintering, thereby 

allowing for “thrifting”, or reducing, the amount of rhodium used (SAE 2011-01-0296). 

Other ongoing refinements to catalyst technology such as higher cell density, thin wall 

substrates and improved catalyst washcoats to enhance oxidation and reduction 

reactions have further improved catalyst performance. 

Because of the continued improvement in the performance of three-way catalysts, most

light-duty vehicles are expected to continue using this technology without the need for 

other aftertreatment devices such as hydrocarbon adsorbers.

 10 “California Test Procedure for Evaluating Substitute Fuels and New Clean Fuels,” adopted November 2, 1993.
Page 30

Improved Catalyst Washcoat and Cell Density: Multi-layer washcoat technologies 

allow optimization of the amount of the precious metal used in the catalyst by reducing 

undesired metal-metal and/or metal-base oxide interactions while allowing desirable 

interactions. Studies have shown that catalyst durability and conversion efficiencies are 

enhanced with improved washcoats (SAE 2009-01-1070, SAE 2008-01-0812, SAE 

2011-01-0301). This improvement in catalyst materials is one of the most significant 

developments that have enabled manufacturers to meet the SULEV standard at a 

relatively low cost.

Cell densities for catalysts vary, depending on catalyst location. Typical cell densities 

for close coupled catalysts used on vehicles meeting SULEV emissions levels are on 

the order of 600 to 900 cells per square inch (cpsi), with some applications utilizing cell 

densities as high as 1200 cpsi. These high cell density catalysts with thin wall 

substrates help reduce catalyst light-off time that is critical for reducing cold-start 

emissions by decreasing the thermal mass of the catalyst. Furthermore, by maintaining 

catalyst volume at the same level, using a higher cell density catalyst increases the 

amount of surface area available for promoting oxidation and reduction reactions.

Increased Catalyst Volume: The ratio of catalyst volume to engine displacement 

determines the space velocity of the catalyst, which in turn determines the residence

time of the exhaust gases in the catalyst. Catalytic converters are sized to provide the 

optimum space velocity needed to meet the emission standard such that the exhaust 

gas residence time in the catalyst is sufficient to allow the necessary oxidation and 

reduction reactions to occur. As a general rule, the larger the displacement of the 

engine, the larger the volume of the catalyst system that is needed. 

Secondary Air: While most vehicles operate lean of stoichiometric or near 

stoichiometric after a cold-start to reduce engine out emissions, for some vehicle 

applications this will not be desirable because of driveability concerns. For these 

vehicles, a brief period of cold operation with a rich A/F mixture may be used to provide 

more stable combustion and better driveability. However, operating rich at start-up 

when the engine is cold increases emissions of unburned HC and CO. Therefore, to 

control these emissions, vehicles that incorporate a rich cold-start fueling strategy are 

expected to include an electric air injection system, also called secondary air, to inject 

air upstream of the three-way catalyst so that a stoichiometric A/F ratio at the catalyst 

can be achieved for optimum emission performance. To further enhance quick catalyst 

light-off, ignition retard in conjunction with supplemental air may also be utilized to 

provide additional heat to the catalyst.

 

Hydrocarbon Adsorber Systems: For some vehicles, particularly those with larger 

displacement engines, the limiting factor for achieving SULEV emission levels may be 

controlling HCs at start-up. One possible solution could be the use of a HC adsorber 

system. Two types of HC adsorber systems for use in motor vehicles have been 

developed. These systems all operate on the same principle, trapping HC emissions 

while the catalyst is cold and unable to convert HCs by utilizing an adsorbing material 

that holds onto the hydrocarbons until the catalyst warms up. One type, commonly 
Page 31

known as an active adsorber system, incorporates valves and channels to bypass the 

primary catalyst on start-up. With this type of adsorber or HC trap, exhaust is 

channeled to the adsorber and trapped during cold start before the catalyst has reached 

light-off. After catalyst light-off, the HC is released and directed to the catalyst for 

treatment. Another adsorber system, known as a passive adsorber, is much simpler in 

design (but is less effective) and does not utilize any valves or other moving parts. In 

this system, HC adsorption material is included in the washcoat of the catalyst. Once 

the catalyst is warmed up, the heat generated by the catalyst releases the trapped HCs 

from the absorption material and are then oxidized by the now fully active catalyst. 

While the principle is simple, the technical solution is not uncomplicated, because 

adsorption and desorption of the HC must be timed correctly to prevent premature 

release of unburned HCs (i.e., the HC must be released only after the catalyst has 

warmed-up).

Optimized Thermal Management: Reducing the time to catalyst light-off is critical to 

reducing cold-start emissions. One effective approach to reducing catalyst light-off time 

is to conserve exhaust heat generated by the engine through the use of optimized 

thermal mass manifolds and insulated exhaust systems. Through the use of laminated 

air-gap exhaust manifolds and thin double-wall exhaust pipes (i.e., manifolds and 

exhaust pipes with metal inner and outer walls and an insulating layer of air sandwiched 

between them), more heat is retained in the exhaust system, enabling quicker catalyst 

light-off. As an added benefit, the use of insulated exhaust pipes also reduces exhaust 

noise.

 

Low Thermal Mass Turbocharger: Since turbochargers are located upstream of the 

catalyst they absorb some of the exhaust heat before it reaches the catalyst. 

Consequently, they present a challenge to achieving quick thermal light-off of the 

catalytic converter in order to reduce cold-start emissions. Reducing the size and 

weight of the turbocharger would reduce its thermal mass, enabling more of the exhaust 

heat to reach the catalyst. Lighter, smaller turbochargers would also improve the 

response time of the turbocharger thereby reducing turbocharger lag (the time the 

turbocharger takes to respond to a power demand by the driver). These lighter, smaller 

turbochargers are currently under development.

 

Reduced Crevice Volumes: Emission performance is also being improved by 

reducing crevice volumes in the combustion chamber. Unburned fuel can be trapped 

momentarily in crevice volumes before being subsequently released. Since trapped 

and re-released fuel can increase engine-out emissions, elimination of crevice volumes 

is beneficial to emission performance. To reduce crevice volumes, vehicle 

manufacturers are designing engines to include pistons with reduced top "land heights 

(the distance between the top of the piston and the first ring). Although reducing the top 

land height could reduce the durability of the piston, improved design and materials 

allow moving the ring higher on the piston.

Reduced Oil Consumption: Lubrication oil leaking into the combustion chamber can 

lead to increased emissions, including emissions of particulate matter, because the 
Page 32

heavier HCs in oil are not easily oxidized and some components in the oil can poison 

the catalyst, reducing its effectiveness. In addition, oil in the combustion chamber may 

trap HCs and later release them unburned. This can be particularly problematic for high 

mileage vehicles as engine wear occurs. To minimize oil consumption, vehicle 

manufacturers are improving the tolerances and surface finish on cylinders and pistons, 

improving piston ring design and materials, and improving exhaust valve stem seals to 

prevent leakage of lubricating oil into the combustion chamber. Virtually all lowemission vehicles with newly redesigned engines incorporate features to reduce oil 

consumption.

Electronic Exhaust Gas Recirculation (EGR): One of the most effective emission 

controls for reducing NOx emissions is exhaust gas recirculation. By recirculating spent 

exhaust gases into the intake manifold to reenter the engine, peak combustion 

temperatures are lowered, reducing NOx emissions. In the past, EGR systems utilized 

an electronic EGR valve actuator in order to provide the precisely-controlled EGR rates 

needed to achieve low NOx levels. Manufacturers are now incorporating variable valve 

control for improved efficiency and lower engine out emissions that provides an internal 

EGR function in their engines. This represents another approach for achieving desired 

EGR rates that may be used solely or in conjunction with electronic EGR valve 

actuators and cooled exhaust gas.

Air Fuel Ratio Sensor (AFS): Vehicles that employ lean at start A/F control strategies 

(i.e., use less fuel than required to achieve a stoichiometric ratio) are utilizing AFSs 

(also called a universal exhaust gas oxygen sensor) for fuel control in lieu of 

conventional oxygen sensors. This is because conventional oxygen sensors are "limit" 

switches in that they can only determine that the engine's A/F ratio is higher or lower 

than stoichiometric; they do not have the capability of recognizing specific A/F ratios. In 

contrast, AFSs are capable of recognizing a wide-range of A/F ratios since the voltage 

output of the AFS is "linear" (i.e., each voltage value corresponds to a certain A/F ratio). 

Therefore, maintaining a lean A/F is attainable with the use of AFS sensors. Since 

operating lean of stoichiometric during cold-start situations can assist heating of the 

catalyst, some low-emission vehicles incorporate these sensors. In addition to their 

capability of maintaining a tight lean A/F, some manufacturers claim AFSs allow the fuel 

control system to maintain a tighter band around stoichiometric, thereby increasing the 

efficiency of the catalytic converter. In this way, AFSs assist vehicles in achieving very 

precise control of the A/F ratio.
Page 33

Central Mounted Fuel Injector (Solenoid): Manufacturers are expected to 

incorporate gasoline direct injection (GDI) engines across their vehicle fleets in the 

future to meet existing and proposed GHG requirements. Gasoline direct injection

engines offer significant GHG benefits due to their inherent efficiency advantage over 

conventional gasoline engines using port fuel injection (PFI). As the nomenclature 

implies, unlike PFI engines that mix the air and fuel in the intake manifold, GDI engines 

inject fuel directly into the combustion chamber that enables higher compression ratios 

and, therefore, improved engine efficiency. However, testing of first generation versions 

of this technology has demonstrated increased levels of particulate matter (PM) 

emissions compared to PM emissions of PFI engines. Testing of later versions of GDI 

engines that use center mounted spray guided fuel injectors has demonstrated the 

potential for these engines to achieve PM emission levels comparable to PFI engines. 

Nonetheless, some manufacturers have stated that they believe they can achieve GDI 

PM emissions levels comparable to that of PFI engines by improving their current side 

mounted fuel injector systems by using higher pressure injectors and minimizing fuel 

impingement on valves, cylinder walls, or other combustion chamber surfaces. 

Individual Cylinder Air/Fuel (A/F) Control: In order to further improve fuel control, 

some vehicles utilize software algorithms to achieve individual cylinder fuel control. 

While dual oxygen sensor systems are capable of maintaining A/F ratios within a narrow 

range, some vehicle manufacturers believe that even more precise control is needed to 

achieve low emissions and have developed individual cylinder control systems. On 

most current vehicles, fuel control is modified whenever the oxygen sensor determines 

that the combined A/F of all cylinders in the engine or engine bank is too far from 

stoichiometric. The needed fuel modifications (i.e., inject more or less fuel) are then 

applied to all cylinders simultaneously. Although this fuel control method will maintain 

the bulk of A/F for the entire engine or engine bank around stoichiometric, it would not 

be capable of correcting for individual cylinder A/F deviations that can result from 

differences in manufacturing tolerances, fuel injector wear, or other factors. With 

individual cylinder fuel control, A/F variation among cylinders will be diminished, thereby 

further improving the effectiveness of the emission control system. By modeling the 

behavior of the exhaust gases in the exhaust manifold and using software algorithms to 

predict individual cylinder A/F, a feedback fuel control system for individual cylinders 

can be developed. Except for the replacement of the conventional front oxygen sensor 

with an AFS sensor and a more powerful engine control computer, no additional 

hardware is needed in order to achieve individual cylinder fuel control. Software 

changes and the use of mathematical models of exhaust gas mixing behavior are 

required to perform this operation. Individual cylinder A/F control also provides an 

opportunity to reduce precious metal content of the catalyst. Control algorithms for 

individual A/F cylinder control have been developed using either conventional switching 

oxygen sensors or wide range air fuel sensors (SAE 2011-01-0710).

Retarded Spark Timing at Start Up: Besides the hardware modifications described 

above, low-emission vehicles also utilize engine calibration changes such as a brief 

period of substantial ignition retard, increased cold idling speed, and leaner air-fuel 

mixtures to quickly provide heat to catalysts after cold-starts. Since only software 
Page 34

modifications are required, engine calibration modifications provide manufacturers with 

an inexpensive method to quickly achieve light-off of catalytic converters. When 

combined with close-coupled catalysts and other heat conservation techniques 

described above, engine calibration techniques can be quite effective at providing the 

required heat to the catalyst for achieving SULEV emission levels. Heat producing 

engine calibrations such as described above are already in production and are widely 

used on low-emission vehicles. 

Diesel Vehicles: In response to existing and proposed GHG and fuel economy 

requirements, some manufacturers are planning to increase the percentage of diesel 

vehicles in their new vehicle fleet. Due to increased levels of engine out NOx from 

diesel engines, this can present a challenge to achieving SULEV emissions for them. 

Significant work is underway by these manufacturers to improve the emission 

performance of diesel vehicles and at least one diesel emission control system with the 

potential to achieve SULEV emissions has been described in the technical literature

(SAE 2008-01-0449). This system incorporates a hydrocarbon trap and diesel oxidation 

catalyst upstream of a lean NOx trap (LNT) and a catalyzed soot filter. The SULEV 

system was based on a Tier 2 Bin 5 system for a 2.8 liter diesel engine and 

demonstrated the potential to meet SULEV emissions at 120,000 miles without 

increasing catalyst volume and precious metal loading. Staff anticipates that future 

diesel vehicles will use a selective catalyst reduction (SCR) system rather than a LNT in 

order to meet USO6 emission requirements. In a SCR system, a reduction agent such 

as urea is injected into the SCR system to promote the reduction of NOx, instead of 

trapping and then reducing NOx using a LNT. Staff expects that similar improvements 

to enable SCR systems to achieve SULEV emissions will be developed.

Direct Ozone Reduction Technologies (DOR): DOR devices involve special coatings 

on radiators or other surfaces in such a way that the amount of ozone in the ambient air, 

which crosses through or across such surfaces, is reduced. The Air Resources Board 

considers these devices to be emission control devices since the NMOG credit accrued 

by such devices is used to offset the exhaust or evaporative emissions of motor 

vehicles. Therefore, the manufacturer must demonstrate the performance and durability 

of such devices for the full useful life of the vehicle, provide an onboard diagnostic 

system to, at minimum, monitor the presence of the device, and provide the appropriate 

emission control warranty. 

3.2. Projected Emission Control Technology Application Rates (Passenger Cars 

and Trucks Less Than 8,501 lbs. GVWR)

From the foregoing list of technologies, it is clear that manufacturers have a wide range 

of options available to achieve SULEV emissions and that many of these technologies 

are already being used today on vehicles meeting the SULEV standard. Table II-A-3-1

below lists the additional emission control technology application rates that staff 

determined may be needed to meet LEV III requirements, over and above those 

currently used on low-emission vehicles. A discussion of the associated costs to meet 

LEV III requirements can be found in section II.A.4.
Page 35

Table II-A-3-1. Additional Emission Control Technology (Passenger Cars and Trucks 

Less Than 8,501 lbs. GVWR)

Additional Emission Control Technology Requirements

Technology component

From ULEV125 to SULEV From LEV160 to SULEV

PC/LDT1

(No of cylinders)

LDT2

(No of cylinders)

PC/LDT1

(No of cylinders)

LDT2

(No of cylinders)

4 6 8 4 6 8 4 6 8 4 6 8

Greater catalyst loading 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100%

Optimized closecoupled catalyst(s) 0% 0% 0% 0% 0% 0% 50% 60% 75% 50% 60% 75%

Secondary air 0% 25% 75% 0% 25% 75% 0% 25% 75% 0% 25% 75%

HC adsorber (active) 0% 0% 0% 0% 0% 15% 0% 0% 0% 0% 0% 15%

Optimized thermal 

mass manifold 25% 25% 25% 25% 25% 25% 25% 25% 25% 25% 25% 25%

Low thermal mass 

turbocharger 0% 0% 0% 0% 0% 15% 0% 0% 0% 0% 0% 15%

Evap equip 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100%

Table II-A-3-2 below lists emission control technologies that generally are already used 

on current low-emission vehicles, or will likely be incorporated on future vehicles to 

meet other requirements such as greenhouse gas emission (GHG) requirements. For

example the use of centrally mounted fuel injection in GDI engines can provide stratified 

air/fuel mixtures in lean-burn engines that combust more completely to reduce NMOG 

and PM emissions while also reducing CO2 emissions. Similarly, digital valve control in 

conjunction with turbocharging and downsized engines can provide lower NOx 

emissions via multiple valve events in each engine cycle while reducing CO2 emissions.
Page 36

Table II-A-3-2. Low-Emission Vehicle Additional Emission Control Technology

Systems that May Used to Some Extent

Technology Component

From ULEV125 to SULEV From LEV160 to SULEV

PC/LDT1

(No of cylinders)

LDT2

(No of cylinders)

PC/LDT1

(No of cylinders)

LDT2

(No of cylinders)

4 6 8 4 6 8 4 6 8 4 6 8

Double layer washcoat & cell density X X X X X X X X X X X X

Engine modifications X X X X X X X X X X X X

Central mounted fuel injector 

(solenoid) X X X X X X X X X X X X

Air Fuel Sensor X X X X X X X X X X X X

Air-assisted fuel injection X X X X X X X X X X X X

Individual cylinder fuel control X X X X X X X X X X X X

Retarded spark timing at start-up X X X X X X X X X X X X

Direct ozone reduction (e.g., 

Premair) X X X X X X X X X X X X

Digital valve control X X X X X X X X X X X X

3.3. Projected Emission Control Technologies (Medium-Duty Vehicles (8,501 -

14,000 lbs. GVW)

Staff performed a similar evaluation of the additional hardware needed for medium-duty 

vehicles. Staff determined that all gasoline medium-duty vehicles would require 

additional catalyst loading and 25 percent would need thermally optimized manifolds. 

Similarly, 25 percent of diesel fueled vehicles would require thermally optimized 

manifolds and 100 percent would need improved selective catalyst reduction (SCR) 

systems. Table II-A-3-3 below lists the additional hardware for gasoline medium-duty 

vehicles that may be needed to meet LEV III requirements.

 

Table II-A-3-3. Additional Emission Control Components (Gasoline Medium-Duty 

Vehicles)

Technology Component

Percent of Technology Needed

8,501-10,000 lbs 

GVWR

10,001-14,000 lbs 

GVWR

8-cylinder

Systems 

with 

additional 

technology 

costs

Greater catalyst loading 100% 100%

Optimized close-coupled catalyst(s) 0% 0%

Secondary air 0% 0%

HC adsorber (active) 0% 0%

Optimized thermal management 25% 25%

Low thermal mass turbocharger 0% 0%

Evaporative equipment 100% 100%
Page 37

Table II-A-3-4 below lists the additional emission control technologies staff determined 

would be required for diesel fueled medium-duty vehicles to meet the proposed 

emission standards.

Table II-A-3-4. Additional Emission Control Components (Diesel Medium-Duty Vehicles)

Technology Component

Percent of Technology Needed

8,501-10,000 lbs 

GVWR

10,001-14,000 lbs 

GVWR

8-cylinder

Systems 

with 

additional 

technology 

costs

Greater catalyst loading 0% 0%

Optimized close-coupled catalyst(s) 0% 0%

Secondary air 0% 0%

HC adsorber (active) 0% 0%

Optimized thermal management 25% 25%

Low thermal mass turbocharger 0% 0%

SCR optimization 100% 100%

4. COST ANALYSIS

4.1. Cost methodology

Costs affecting vehicle price are generally assigned to direct costs (cost of hardware to 

the manufacturer) and indirect costs (research and development, warranty, corporate 

salaries, pensions, health care, transportation, dealer support and marketing). In past 

rulemakings, staff developed retail price equivalent factors (RPE) that assumed 

incremental increases in direct costs resulted in a constant percentage increase to all 

indirect costs. In general, RPE can be expressed by:

RPE = (direct costs + indirect costs + profit)/(direct manufacturing costs)

In this cost analysis, staff relied on recent work by the USEPA that developed a 

modified multiplier, referred to as an indirect cost multiplier (ICM), by evaluating the 

components of indirect costs that are most likely to be affected by regulation-induced 

vehicle modifications. For example, while an improved catalyst may contain greater 

precious metal loading and therefore higher direct cost to the manufacturer, there is no 

reason to expect that this would result in increased labor costs or other indirect costs 

such as pension and health costs to install the catalyst in a vehicle. The ICMs 

developed by this work also included a more refined approach to determine indirect 

costs by taking into consideration the complexity of the technology employed (see 

Rogozhin et al 2009, 2010). The ICMs have been further refined in the latest technical 

analysis by USEPA (see USEPA and NHTSA, 2011c). Based on the latest USEPA 

development of the ICM factors, Table II-A-4-1 below lists the ICMs that are applied in 

this incremental cost analysis.
Page 38

Table II-A-4-1. Indirect Costs Multipliers

Complexity Indirect Cost Multiplier

Long-Term

Low 1.19

Medium 1.29

As a first step, staff performed a comprehensive cost analysis of direct costs for the 

proposed LEV III exhaust emission requirements applicable to passenger car, light-duty 

trucks and medium-duty vehicles. Specifically, staff estimated the incremental direct 

component costs of a SULEV30 vehicle compared to a LEV160 vehicle and a ULEV125 

vehicle for passenger cars and light-trucks less than 8500 lbs. GVWR for four-, six-, and 

eight-cylinder applications. These comparisons were chosen because their costs

represent the highest costs manufacturers would incur in achieving SULEV emission 

levels across their fleet. Model year 2008 California new vehicle fleet, the latest year 

complete fleet data were available, was used to determine the fleet mix of vehicles

using four-, six-, and eight-cylinder engines in each of the vehicle categories of 

PC/LDT1 and LDT2. Table II-A-4-2 below shows a breakdown of the new vehicle fleet 

mix for the 2008 model year. Staff notes that this cost assessment is inherently 

conservative for several reasons. The projected technology requirements for model year 

2025 represent component costs for all vehicles to meet the most stringent 

requirements of LEV III (whereas some models will utilize less stringent certification 

levels, e.g., ULEV50). In addition, based on manufacturers’ plans, it appears likely that 

by 2025 a greater portion of the fleet will consist of vehicles using downsized engines 

that have the lower compliance costs. 

Table II-A-4-2. 2008 California Fleet Emission Certification Level Mix

Category Certification 

Level 4-cyl 6-cyl 8-cyl

PC/LDT1

LEV 44% 45% 12%

ULEV 64% 29% 8%

SULEV 79% 20% 0%

LDT2

LEV 8% 71% 20%

ULEV 3% 59% 38%

SULEV 53% 47% 0%

PC/LDT1 overall 66% 28% 6%

LDT2 overall 7% 61% 32%

In assessing the incremental costs, staff first defined the additional systems and 

technologies that would be used by manufacturers to meet the proposed emission 

levels. Staff relied on confidential information provided by vehicle manufacturers, 

emission control component suppliers, the technical literature and staff’s engineering 

evaluation of the likely need for additional emission control hardware. In addition, staff 

worked closely with the USEPA in developing these costs, since the goals of LEV III 
Page 39

and the federal Tier 3 program currently under development are very similar (fleet 

SULEV emissions levels in 2025). 

After considerable discussion, a consensus was reached on the most likely 

configurations of emission control systems needed to meet LEV III program 

requirements. Tables II-A-3-1 above list staff’s evaluation of the additional emission 

control components needed to meet SULEV30 emission levels.

4.2. Cost Analysis

4.2.1. Passenger cars and Light-Duty Trucks

Once the most likely additional emission hardware likely to be used to meet SULEV

emissions had been determined, staff then assigned costs for each component. Costs 

for these components were derived from vehicle manufacturers, emission control 

component suppliers and staff assessment of existing data. Tables II-4-1 and Table II4-2 in list the manufacturers’ direct costs for additional emission control components 

and the resulting incremental increase in vehicle price in 2025 in 2009 dollars. Annual 

cost reductions of 3% per year for 2015-2020 and 2% per year for 2021-2025 were

applied to the direct costs to reflect reductions in manufacturing costs due to learning 

and continual technical improvements in emission control technology. A Low

complexity long-term ICM of 1.19 was applied to all components, with the exception of 

the HC adsorber where a Medium long-term ICM of 1.29 was used to reflect the 

increased complexity of incorporating this component into the vehicle emission control 

system. Staff assigned no additional costs for compliance with the proposed PM 

standards for two reasons. First, staff concluded that, since the proposed PM standards 

would be met by engine modifications during the normal course of engine development, 

no incremental increase in vehicle price would occur as a result. In addition, staff is 

optimistic that real-time measurement procedures would be developed in the requisite 

timeframe such that costs for any additional PM testing facilities would be negligible on 

a per-vehicle basis.

Table II-4-1 Cost of Additional Emission Control Components (LEV160 to 

SULEV30)

Technology Component

From LEV to SULEV

PC/LDT1 LDT2

4-cyl 6-cyl 8-cyl 4-cyl 6-cyl 8-cyl

Systems 

with 

additional 

technology 

costs

Greater catalyst loading $47 $62 $78 $47 $62 $78

Optimized close-coupled catalyst(s) $8 $19 $35 $8 $19 $35

Secondary air $0 $19 $58 $0 $19 $58

HC adsorber (active) $0 $0 $17 $0 $0 $17

Optimized thermal management $6 $6 $6 $6 $6 $6

Low thermal mass turbocharger $0 $0 $0 $0 $0 $0

Evap equip $13 $13 $13 $13 $13 $13

 Total incremental cost $73 $119 $207 $73 $119 $207

 Total incremental price $87 $142 $248 $87 $142 $248
Page 40

 

Table II-4-2 Cost of Additional Emission Control Components (ULEV125 to 

SULEV30)

Technology Component

From ULEV to SULEV

PC/LDT1 LDT2

4-cyl 6-cyl 8-cyl 4-cyl 6-cyl 8-cyl

Systems 

with 

additional 

technology 

costs

Greater catalyst loading $23 $31 $39 $23 $31 $39

Optimized close-coupled catalyst(s) $0 $0 $0 $0 $0 $0

Secondary air $0 $19 $58 $0 $19 $58

HC adsorber (active) $0 $0 $17 $0 $0 $17

Optimized thermal management $6 $6 $6 $6 $6 $6

Low thermal mass turbocharger $0 $0 $0 $0 $0 $0

Evap equip $13 $13 $13 $13 $13 $13

 Total incremental cost $42 $69 $134 $42 $69 $134

 Total incremental price $50 $83 $161 $50 $83 $161

4.2.2. Medium-Duty Vehicles

Staff performed a similar cost analysis of the additional hardware needed for mediumduty vehicles. Again, costs for these components were derived from vehicle 

manufacturers, emission control component suppliers and staff judgment. Table II-A-4-

3 below lists the incremental hardware for gasoline medium-duty vehicles that may be 

needed to meet LEV III requirements. 

 

Table II-A-4-3. Additional Emission Control Components (Gasoline Medium-Duty 

Vehicles)

Technology Component

Cost of Technology Needed

8,501-10,000 lbs 

GVWR

10,001-14,000 lbs 

GVWR

8-cylinder

Systems 

with 

additional 

technology 

costs

Greater catalyst loading $40 $40

Optimized close-coupled catalyst(s) $0 $0

Secondary air $0 $0

HC adsorber (active) $0 $0

Optimized thermal management $6 $6

Low thermal mass turbocharger $0 $0

Evaporative equipment $17 $17

Total incremental direct cost $62 $62

Total incremental vehicle price $75 $75

Table II-A-4-4 lists the additional hardware that may be needed for diesel medium-duty 

vehicles.
Page 41

Table II-A-4-4. Additional Emission Control Components (Diesel Medium-Duty Vehicles)

Technology Component

Cost of Technology Needed

8,501-10,000 lbs 

GVWR

10,001-14,000 lbs 

GVWR

8-cylinder

Systems 

with 

additional 

technology 

costs

Greater catalyst loading $0 $0

Optimized close-coupled catalyst(s) $0 $0

Secondary air $0 $0

HC adsorber (active) $0 $0

Optimized thermal management $6 $6

Low thermal mass turbocharger $0 $0

Evaporative equipment $0 $0

SCR optimization $40 $40

Total incremental direct cost $45 $45

Total incremental vehicle price $54 $54

4.3. Incremental Cost of the Standards

From the cost analysis described above, the following conclusions are drawn.

• Based on the 2008 fleet breakdown by engine size and initial certification level, 

the projected average incremental retail prices for light-duty LEV III vehicles in 

2025 are shown in Table II-A-4-5.

Table II-A-4-5. Incremental vehicle price increase for 2025 criteria pollutant compliance

Vehicle

Category

Initial baseline

certification level

Engine size Average 

incremental

pricea

($/vehicle)

Average 

incremental 

priceb ($/vehicle) 4-cyl 6-cyl 8-cyl

PC/LDT1

LEV $87 $142 $248 $130

ULEV $50 $83 $161 $68 $55

SULEV $0 $0 $0 $0

LDT2

LEV $87 $142 $248 $159

ULEV $50 $83 $161 $111 $117

SULEV $0 $0 $0 $0 a Sales-weighted average for each initial certification level b Sales-weighted average for vehicle category

• The average cost-effectiveness of light-duty vehicles meeting the LEV III 

program exhaust requirements relative to the 2008 fleet is approximately $4.00 

per pound of NMOG + NOx reduced. Motor vehicle control measures typically 

range up to $5 per pound of emissions while stationary source controls range up 

to $10 per pound of emissions reduced.

• The projected average incremental price increase in 2025 for medium-duty 
Page 42

vehicles is $75 for gasoline fueled vehicles and $54 for diesel fueled vehicles.

5. OUTSTANDING ISSUES

While developing this proposal, staff worked with the USEPA in an effort to provide as 

much consistency as possible between LEV III requirements and the federal Tier 3 

program currently under development, while still meeting California criteria emission 

reduction needs. In addition, California test procedures contain extensive references to 

sections of the federal Code of Federal Regulations (CFR) pertaining to test procedures 

and protocols for demonstration of compliance to the emission standards. Since the 

Tier 3 program is not expected to be finalized and incorporated into the CFR until 

sometime in 2012 after the scheduled Board hearing for LEV III, staff will need to 

update the test procedure references subsequent to the Board’s consideration of the 

LEV III regulations. If Tier 3 is finalized and the CFR updated with sufficient time 

remaining before the LEV III regulatory package is due to the Office of Administrative 

Law, staff plans to issue a 15-day notice on the revisions to the test procedure 

references. Otherwise, staff will return to the Board after these amendments are 

adopted in final form, to present updated test procedures for the Board’s consideration.

6. REGULATORY ALTERNATIVES TO EXHAUST CRITERIA POLLUTANT 

EMISSION PROPOSAL

As noted in the introduction to section II, significant reductions of criteria emissions are 

needed if California is to achieve federal and state health based air quality standards. 

Staff has presented a LEV III proposal above that it believes achieves the maximum 

cost-effective and feasible reductions for the timeframe considered. The proposed LEV 

III program will result in significant emission reductions from the light-duty fleet by 2025 

and beyond. Nonetheless, staff considered three alternatives to the proposed LEV III 

program in an effort to determine whether other approaches could achieve equivalent or 

greater emission reductions.

6.1. Do Not Amend Current California LEV Program

Many areas of California are still designated as non-attainment for federal and State 

ambient air quality standards. Light- and medium-duty vehicles are a major contributor 

to the emission inventory and with increasing vehicle population and vehicle miles 

traveled, their contribution to the emission inventory will also increase. In order to 

achieve healthful air quality and make further progress towards meeting federal and 

State ambient air quality standards, further reductions in mobile source emissions are 

needed. In addition, California’s LEV program for criteria pollutants would likely differ 

from, and be less stringent than, comparable federal standards, presenting a potential 

issue for EPA’s consideration of California’s request for a waiver pursuant to Clean Air 

Act Section 209(b). As a result, staff believes that not amending the LEV III criteria 

pollutant standards is not a reasonable alternative. 

6.2. Adopt Less Stringent Standards
Page 43

Staff believes that consideration of less stringent standards would put the State at risk 

of not achieving the emission reduction goals of the SIP. Given the large amount of 

emission reductions that are still needed to achieve federal and State ambient air quality 

standards, staff believes that any relaxation of the LEV III proposal would seriously 

impact California’s ability to achieve its air quality goals.

6.3. Adopt More Stringent Standards

The proposed LEV III program requires new light-duty fleet emissions to be reduced to 

SULEV NMOG and NOx emission levels by 2025. This represents an emission level 

that approaches the very low power plant emissions associated with the recharging of 

battery electric vehicles. In developing the LEV III proposal, staff held numerous 

meetings with vehicle manufacturers and emission component suppliers in order to 

determine the most cost-effective approach to achieving these low levels given 

manufacturers’ resource constraints of lead-time and costs to incorporate advanced 

emission control technology across their vehicle lines. Staff determined that requiring a 

more aggressive reduction in fleet emissions would result in substantial vehicle cost 

increases to the consumer and place a significant compliance burden on the 

manufacturers without a commensurate reduction in emissions.

B. CALIFORNIA'S EVAPORATIVE EMISSION REGULATIONS

1. BACKGROUND

1.1. Evaporative Emissions

Evaporative emissions consist of fuel hydrocarbon vapors from a motor vehicle, which

are released into the atmosphere. Evaporative emissions are classified into three 

types: running loss, hot soak, and diurnal. Running loss emissions occur during vehicle 

operation, originating from various sources within the fuel system and from fuel vapor 

overflow of the on-board carbon canister. Hot soak emissions occur immediately after 

the termination of engine operation, when latent engine heat vaporizes residual fuel in 

the engine system. Diurnal emissions are caused by daily cycling of ambient 

temperatures when a vehicle is parked, where ambient temperature increases result in 

fuel tank vapor generation. Another type of emissions, refueling emissions, occurs 

during refueling of the vehicle when the entering liquid fuel volumetrically displaces the 

fuel vapors in the fuel tank.

One main source of vehicular evaporative emissions is the carbon canister, where 

excess vapors in the fuel tank are routed for storage instead of being released into the 

atmosphere. In many evaporative emission systems, the canister also captures fuel 

tank vapor emissions during refueling as part of onboard refueling vapor recovery 

(ORVR.) The carbon canister is regenerated during vehicle operation when the fuel 

vapors stored in the canister are purged into the engine’s intake system and 

subsequently burned in the combustion process. Substantial evaporative emission 
Page 44

losses from the canister occur when the generated fuel tank vapors routed to the 

canister are greater than its storage capacity, and thus, hydrocarbon escape from the 

canister into the atmosphere. In addition, small evaporative losses from the canister, 

called bleed emissions, result when hydrocarbon emissions escape the canister due to 

diffusion of adsorbed hydrocarbons as the vehicle rests over a period of time. Another 

main source of evaporative emissions is through permeation of fuel through elastomeric 

hoses, joints, and valves, as well as through plastic fuel tanks.

1.2. Current Evaporative Standards and Test Procedures

Compliance with the current evaporative emission regulations, adopted as part of the 

LEV II Program, is based on meeting three separate certification “whole vehicle”

emission standards. Specifically, these include the running loss emission standard, the 

three-day diurnal plus high-temperature hot soak (three-day) emission standard, and 

the two-day diurnal plus moderate-temperature hot soak (two-day) emission standard.11 

The running loss emission standard ensures evaporative emission control during 

vehicle driving. The three-day emission standard ensures that the evaporative system 

can control evaporative emissions for three consecutive hot summer days. The two-day 

emission standard ensures an effective purging strategy of the vehicle carbon canister. 

These standards are shown in Table II-B-1-1.

As an option, a manufacturer may certify its passenger cars and light-duty trucks to 

more stringent requirements by complying with zero-evaporative emission standards. 

Specifically, these requirements consist of more stringent three-day and two-day whole 

vehicle emission standards, as well as a “zero” fuel evaporative emission standard. 

Over the two-day and three-day test procedures, passenger cars must meet a 0.35 

grams per test hydrocarbon emission standard (higher levels are allowed for larger 

vehicles as shown in Table II-B-1-1), which includes fuel and non-fuel hydrocarbon 

emissions. They must also meet the zero-evaporative emission standards, which 

require a vehicle to emit no more than 0.054 grams per test of fuel-only evaporative 

emissions. Currently, manufacturers certify to zero-evaporative emission standards in 

order to qualify for PZEV credits under the ZEV regulatory mandate. This can occur 

only if the vehicle’s exhaust emissions are also certified to SULEV exhaust standards 

with a 150,000-mile useful life and a 150,000 mile warranty.

 11 Compliance with the running loss and three-day emission standards is demonstrated over a three-day 

diurnal test procedure. Compliance with the two-day emission standard is demonstrated over a two-day 

diurnal test procedure.
Page 45

Table II-B-1-1. Current LEV II evaporative emission standards

Vehicle type

Hydrocarbon standards

Running loss

(grams per test)

Three-day diurnal plus 

hot soak 

(grams per test)

Two-day diurnal plus

hot soak 

(grams per test)

Passenger cars 0.05 0.50 0.65

Light-duty trucks

6,000 lbs. GVWR and under 0.05 0.65 0.85

Light-duty trucks from 

6,001-8,500 lbs. GVWR 0.05 0.90 1.15

Medium-duty vehicles

(8,501-14,000 lbs. GVWR) 0.05 1.00 1.25

Heavy-duty vehicles

(over 14,000 lbs. GVWR) 0.05 1.00 1.25

1.3. Rulemaking Considerations

In the 2010 model year, 28 percent of passenger cars and light-duty trucks were 

certified (as PZEVs) to the zero-evaporative emission standards. As part of the 

proposed Advanced Clean Cars Program, the proposed changes to the ZEV program12

would disallow conventional gasoline vehicles to accrue PZEV credits beyond the 2018 

model year. Thereafter, no incentive exists to certify a vehicle to meet the zeroevaporative emission standards, and thus, mandatory regulatory requirements are 

needed to continue and increase zero-evaporative certified vehicles. The proposed 

LEV III evaporative emission standards would not only continue the zero-evaporative 

requirements beyond 2018 for PZEVs but also extend them to the remaining vehicles in 

the passenger car and light-duty truck vehicle categories as well as to the heavier 

vehicle categories.

Another major consideration that surfaced during the rulemaking process was the 

requirement to demonstrate compliance with the fuel-only emission standard. This 

demonstration currently requires the construction of an apparatus, or “rig”, composed of 

fuel and evaporative system components (e.g., the fuel tank, fuel hoses, carbon 

canister, etc.) for each zero-evaporative emission family. The rig is used to 

demonstrate compliance with the 0.0 grams per test emission standard over the twoday and three-day test procedures. Under the current regulations, this demonstration 

does not impose a significant burden on manufacturers because the number of vehicles 

certifying to the zero-evaporative emission standard is relatively low. However, 

manufacturers contend that the proposed regulations (i.e., requiring all vehicles to 

comply with the zero-evaporative emission standard) would result in a significantly 

increased testing burden. Thus manufacturers have requested that the rig test 

requirement be eliminated. Manufacturers have argued that the rig test is unnecessary 

because the whole vehicle evaporative emission standards are low enough to ensure 

sufficient control of fuel evaporative emissions. Staff disagrees. Current certification 

 12 Proposed revisions to ARB’s ZEV Program are a separate but concurrent rulemaking as part of the Advanced 

Clean Cars package of regulatory measures.
Page 46

data on zero-evaporative emission families show that 8 percent of families are certified 

to whole-vehicle diurnal plus hot soak emission levels less than 0.150 grams per test 

compared to a 0.35 grams per test emission standard. If the rig test is eliminated, the 

opportunity would exist for a manufacturer to increase fuel emissions on these lowcertifying zero-evaporative vehicles but still comply with the whole-vehicle emission 

standards. To resolve this issue, staff’s proposal includes a compliance option (Option 

2) that addresses both staff’s and manufacturers’ concerns.

2. SUMMARY OF PROPOSED AMENDMENTS

2.1. Proposed Evaporative Emission Standards

To maintain continuity of vehicles certified to the zero-evaporative emission standards 

and to expand the use of existing zero-evaporative technology to the remaining vehicle 

classes, staff proposes to require all passenger cars, light-duty trucks, medium-duty 

vehicles, and heavy-duty vehicles that are gasoline-fueled, liquefied petroleum gasfueled, and alcohol-fueled, to comply with the zero-evaporative emission standards. 

This would require amending section 1976, title 13, California Code of Regulations

(CCR) (Appendix A) and the incorporated “California Evaporative Emission Standards 

and Test Procedures for 2001 and Subsequent Model Motor Vehicles” (Appendix F). 

The proposed lower evaporative emission standards are equivalent in stringency to the 

optional LEV II zero-evaporative emission standards. 

2.1.1. Compliance Options

Two options for complying with the zero-evaporative emission standards are proposed. 

Note that the current running loss emission standards and the vehicle evaporative 

durability requirement (also known as “useful life”) of 15 years or 150,000 miles, 

whichever first occurs, would remain unchanged from LEV II levels.

a. Option 1 – Whole-vehicle plus fuel-only evaporative emission 

standards

In this option, the proposed evaporative emission standards for passenger cars and 

light-duty trucks are identical to the current optional zero-evaporative emission 

standards which are currently used by manufacturers to earn PZEV credits, as shown in 

Table II-B-2-1. However, the proposed Option 1 whole-vehicle emission standards are 

35 to 46 percent lower than the current non-zero-evaporative LEV II two-day emission 

standard and 17 to 30 percent lower than the current non-zero-evaporative LEV II threeday emission standard, depending on the vehicle type.
Page 47

Table II-B-2-1. Proposed option 1 evaporative emission standards

Vehicle type

Hydrocarbon emission standards

Running loss 

(grams per miles)

Three-day diurnal + hot soak, and 

two-day diurnal + hot soak

Whole vehicle 

(grams per test)

Fuel only

(grams per test)

Passenger car 0.05 0.350 0.0

Light-duty truck

6,000 lbs. GVWR and under 0.05 0.500 0.0

Light-duty truck from 

6,001-8,500 lbs. GVWR 0.05 0.750 0.0

Medium-duty passenger vehicle 0.05 0.750 0.0

Medium-duty vehicle

(8,501-14,000 lbs. GVWR) 0.05 0.750 0.0

Heavy-duty vehicle

(over 14,000 lbs. GVWR) 0.05 0.750 0.0

b. Option 2 – Whole-vehicle evaporative emission standards with a fleet 

average option and a canister bleed test requirement

Option 2 would provide manufacturers another compliance path while maintaining the 

same stringency level as Option 1. To address manufacturers’ concern of an overly 

burdensome rig test, Option 2 would eliminate this requirement. But to maintain and 

ensure adequate fuel evaporative control, two other major revisions, compared to 

Option 1, are proposed. Specifically, for Option 2, staff proposes to increase the 

stringency of the whole-vehicle emission standards and require manufacturers to 

demonstrate compliance with a new “canister bleed test, which verifies the vehicle’s 

ability to prevent hydrocarbon diffusion from the canister into the atmosphere.”13 The 

proposed Option 2 emission standards are shown in Table II-B-2-2. The canister bleed 

test would ensure that the vehicle’s carbon canister is optimally designed using the best 

control technology and that adequate canister purge occurs during vehicle operation. 

Based on staff’s discussions with emission control industry experts, canister bleed 

emission values from current zero-evaporative systems are below the level of detection 

and therefore meet the proposed emission standards, with the exception of a few hybrid 

vehicles. As described in the subsequent technology section, staff believes additional 

technologies may be needed in some cases to enable hybrid systems to meet the 

proposed standard. Staff is confident that the combination of the lower whole-vehicle 

standard and the canister bleed test would be equally effective in ensuring equivalent 

emission control as compared to the current zero-evaporative emission standards. 

Option 2 would also allow manufacturers to demonstrate compliance with the proposed

diurnal plus hot soak emission standard through fleet averaging. For example, if a 

manufacturer’s evaporative fleet average certification emission level for a particular 

 13 The canister bleed test, significantly less costly and burdensome compared to the rig test, is described in further 

detail in section II.B.2.1.4, “Test Procedure Modifications.”
Page 48

emission standard category equals, or is less than, the applicable emission standard, 

the manufacturer would be in compliance for that given emission standard category. 

However, if the manufacturer’s fleet average level for an emission standard category 

exceeds the applicable emission standard, the manufacturer would incur evaporative 

emission debits and be required to offset these debits within three model years with 

emission credits earned in previous or subsequent model years. If the debits are not 

offset after the three model year period, the manufacturer may be subject to civil 

penalties. Under this proposed fleet averaging provision, evaporative emission credits 

could be used for the five model years following the model year in which they are 

earned to offset any evaporative emission debits in the same emission standard 

category. Furthermore, the manufacturer may also use the emission credits from the 

passenger car and smallest light-duty truck emission standard category to offset debits 

from other emission standard categories at the end of the debit offset period.

Under Option 2, compliance determination using the three-day and two-day test results 

would differ from the methodology used in the existing regulations. The current 

methodology uses the three-day and two-day test results and compares them 

individually with their respective emission standards for each test. However, under the 

proposed Option 2, the higher emission result between the two tests would be used to 

determine compliance with the emission standard.

Table II-B-2-2. Proposed option 2 evaporative emission standards

Vehicle type

Hydrocarbon emission standards

Running loss

(grams per test)

Highest diurnal plus

hot soak 

(grams per test)

Canister bleed 

(grams per test)

Passenger car; and 

Light-duty truck

6,000 lbs. GVWR and under, and 

0 – 3,750 lbs. LVW

0.05 0.300 0.020

Light-duty truck 

6,000 lbs. GVWR and under, and 

3,751 – 5,750 lbs. LVW

0.05 0.400 0.020

Light-duty truck 

6,001 - 8,500 lbs. GVWR; and 

Medium-duty passenger vehicle

0.05 0.500 0.020

Medium-duty vehicles 

(8,501 – 14,000 lbs. GVWR); and 

Heavy-duty vehicle

(over 14,000 lbs. GVWR)

0.05 0.600 0.030
Page 49

2.1.2. Proposed Implementation Schedule

The proposed implementation of the LEV III evaporative emission standards would 

begin in the 2015 model year and be phased in through the 2022 model year, as shown 

in Table II-B-2-3. In the 2015 through 2017 model years, the proposed minimum 

percent requirement would be the average percentage of vehicles generating PZEV 

credits in a manufacturer’s vehicle fleet for the previous three model years, i.e., 2012, 

2013, and 2014. The proposed 2015 through 2017 model year requirement would 

ensure that a manufacturer maintains at least the same percentages of zeroevaporative vehicles as previous model years. The proposed phase-in of the LEV III 

evaporative standards would increase to 60 percent in the 2018 model year, to 80 

percent in the 2020 model year, and to full implementation in the 2022 and later model 

years. 

An alternate phase-in schedule to comply with the phase-in requirements is also 

proposed, which would provide added flexibility to manufacturers. The alternate phasein schedule would allow manufacturers to select phase-in percentages that are different 

than those indicated in Table II-B-2-3 so long as it is shown that an equivalent weighted 

compliance volume of phased-in vehicles would be achieved by 2022. This alternative 

phase-in schedule could only be applied to the 2018 through 2022 model years.

Table II-B-2-3. Proposed evaporative standard implementation schedule

Model year Minimum percentage of vehicle fleet

2015 to 2017 Average of previous 

3 model year PZEVs

2018 to 2019 60

2020 to 2021 80

2022 and subsequent 100

2.1.3. E10 Certification Fuel Phase-In Schedule

As part of the Advanced Clean Cars Program, staff is proposing to amend certification 

test fuel specifications by eliminating required testing with MTBE laden fuel, and 

requiring 10 percent ethanol by volume instead, as discussed in section IV. This 

proposed modification would better align the specifications of certification test fuel with 

the properties of in-use fuel. It is proposed that all vehicles certifying to the LEV III 

evaporative emission standards would be certified using the proposed test fuel with 10 

percent volume ethanol, and that by the 2020 model year all evaporative emission 

certifications would be certified using the proposed test fuel with 10 percent volume 

ethanol.

2.1.4. Test Procedure Modifications

As briefly mentioned earlier, a canister bleed test would be required when certifying 

under Option 2. This proposed test procedure involves component testing of the 

vehicle’s carbon canister while connected to the vehicle’s fuel tank, and generally 
Page 50

mimics the two-day test procedure. In this procedure, the canister would be stabilized 

to a 4,000-mile test condition and preconditioned through loading and purging. The 

canister would then be connected to the fuel tank vent port, and both the canister 

system and the fuel tank placed in a testing enclosure where the ambient temperature is 

cycled between 65°F and 105°F, for a period of two 24-hour cycles. To determine 

compliance with the proposed canister bleed test, the amount of hydrocarbons emitted 

over each 24-hour period would have to be equal to or less than the proposed emission 

standard. The proposed canister bleed test requires substantially less time and is less 

labor-intensive than the rig test manufacturers currently perform for the zeroevaporative emission standards, although the canister bleed test is not as 

comprehensive as the rig test, which tests every evaporative emission control and fuel 

system component. However, staff believes the proposed canister bleed test and 

standards coupled with the proposed Option 2 lower whole vehicle standards would be 

equally effective in ensuring equivalent emission control as the current zero-evaporative 

emission standards.

2.1.5. Pooling Evaporative Emissions from California and Section 177 States 

Beginning in 2015, staff is proposing to provide an option to allow compliance with the 

fleet average Highest Diurnal plus Hot Soak requirement, set forth in section 

II.B.2.1.1.b., be demonstrated using the pooled fleet average of the Highest Diurnal plus 

Hot Soak emission values of new vehicles produced and delivered for sale in California 

and all states, including the District of Columbia if applicable, that adopt California’s 

evaporative emission requirements for light-, medium-, and heavy-duty vehicles. Staff 

is also proposing to allow pooling to comply with the phase-in requirements discussed in 

section II.B.2.1.2. Manufacturers that choose this option would be required to report the 

number of vehicles produced and delivered for sale and the emission standards, and 

family emission limits, if applicable, to which they are certified for each state, and the 

District of Columbia if applicable, that adopts California emission 

requirements. Including this provision provides additional compliance flexibility to 

vehicle manufacturers, particularly with respect to meeting a separate fleet average 

requirement in those states with limited new vehicle sales. While this represents a 

departure from past practice, staff believes that the emission impact of this provision 

within California and states that adopt California requirements will be minor due to the 

very low level of fleet emissions required by this program.

2.2. Proposed Onboard Refueling Vapor Recovery (ORVR) Amendments

The ORVR regulations were previously updated in 2009 for changes related to plug-in 

hybrid vehicles. The changes proposed in LEV III are to bring the applicability of ORVR 

standards into alignment with the current federal regulations and expected Tier 3 

amendments to 40 CFR §86-1811-04(e)(3). California’s current ORVR standards (13

CCR §1978) only apply to vehicles up to 8,500 pounds GVWR. The proposed change 

would increase the applicability of the ORVR requirements to complete vehicles up 

through 14,000 pounds GVWR inclusive. The proposed regulatory language for section 

1978, title 13, CCR is provided in Appendix A. The “California Refueling Emission 
Page 51

Standards and Test Procedures for 2001 and Subsequent Model Motor Vehicles” is 

incorporated by reference into section 1978, title 13, CCR and proposed revisions to the 

incorporated test procedures are provided in Appendix G. 

Under the current federal ORVR regulations, complete vehicles up through 10,000 

pounds GVWR are required to meet the ORVR standards. However, OEMs have 

indicated that complete vehicles up through 14,000 pounds GVWR contain ORVR 

equipment in an effort to minimize evaporative system variants among the MDV class. 

Thus, to come into alignment with current practice and prevent future backsliding, staff 

is proposing that, beginning with model year 2015, complete vehicles up through 14,000 

pounds GVWR comply with the ORVR standards. The proposed LEV III standards are 

unchanged from the LEV II standards of 0.20 grams hydrocarbons per gallon of fuel 

dispensed for gasoline-fueled, diesel-fueled, and hybrid electric vehicles (hydrocarbons 

mean organic material hydrocarbon equivalent for alcohol-fueled vehicles), and 0.15 

grams hydrocarbons per gallon of fuel dispensed for liquefied petroleum gas-fueled 

vehicles.

In addition to increasing the GVWR applicability, staff is proposing an option to allow 

OEMs to use California certification fuel (gasoline with 10 percent ethanol) during the 

certification testing in lieu of federal certification fuel, with the provision that California 

test temperatures are also used (Appendix G). This change is being proposed to allow 

streamlining between the ORVR and evaporative emission testing when California 

certification fuel is used for evaporative emission testing. The proposed increase in the 

refueling temperature from 67°F ± 1.5°F to 79°F ± 1.5°F if California certification fuel is 

used would ensure comparability with the federal test procedures and test fuels, which 

have a higher vapor pressure but lower test fuel temperature. The vehicle soak 

temperature would remain unchanged in order to ensure equivalent stringency 

regardless of the certification fuel used.

The proposed changes to the ORVR regulations and test procedures are not expected 

to result in any emission reduction or OEM cost due to current federal requirements for 

vehicles 8,501 through 10,000 pounds GVWR, OEM practice for vehicles 10,000 

through 14,000 pounds GVWR, and use of on-site vapor recovery at refueling stations 

located in ozone non-attainment areas. Thus, these proposed changes serve to 

harmonize California and federal regulatory requirements and ensure the best available 

refueling vapor recovery systems on all complete vehicles equal to or less than 14,000 

pounds GVWR.

2.3. Proposed Amendments to the Specifications for Fill Pipes and Openings of 

Motor Vehicle Fuel Tanks

The specifications for fill pipes and openings of motor vehicle fuel tanks (13 CCR 

§2235) were last amended in 1990 and were based upon Society of Automotive 

Engineers (SAE) specifications that have since been withdrawn and superseded by the 

International Organization for Standardization (ISO) standard, “Road vehicles – Filler 

pipes and openings of motor vehicle fuel tanks – Vapour recovery system” (ISO 13331-
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1995(E)). This ISO standard is based upon the original SAE standards, but addresses 

several errors and clarifies aspects of the design criteria. 

In order to bring the “Specifications for Fill Pipes and Openings of Motor Vehicle Fuel 

Tanks” up to date with the most current industry standards, staff is proposing to revise 

the current specifications so that they would be applicable only through model year 

2014 (Appendix H). Beginning with model year 2015, the specifications based on the 

SAE standards ("Specifications for Fill Pipes and Openings of 1977 through 2014 Model 

Motor Vehicle Fuel Tanks") would be sunsetted and replaced by new specifications that 

incorporate the ISO standards by reference ("Specifications for Fill Pipes and Openings 

of 2015 and Subsequent Model Motor Vehicle Fuel Tanks"). The proposed specification 

language for 2015 and subsequent model year vehicles is available in Appendix I. 

Because the fill pipe specifications in the ISO-13331-1995 standard are substantially 

similar to and primarily clarifications of the SAE specifications referenced in the 1990 

revision of 13 CCR Section §2235, no OEM changes for compliance are anticipated. All 

test procedures would continue to be required and would be unchanged from the 1990 

amendments. 

3. TECHNOLOGICAL FEASIBILITY OF PROPOSED STANDARDS

3.1. Current Evaporative Emission Technology

Today’s most advanced evaporative emission control technologies are in vehicles 

meeting the optional zero-evaporative emission standards. The current state-of-the-art 

in evaporative technology is described in the ensuing paragraphs. Evaporative 

emission control technology can basically be grouped into three categories: carbon 

canister system, fuel storage / delivery system, and air intake system.

3.1.1. Carbon Canister System 

A carbon canister system is employed to adsorb hydrocarbon vapors generated in the 

fuel tank during a refueling event, during vehicle operation, and while the vehicle is 

parked. These vapors are adsorbed by activated carbon granules contained in the 

canister. Canister system emissions generally fall into two categories: breakthrough 

and bleed. In a typical evaporative test sequence, breakthrough is the point when 2.0 

grams of hydrocarbon has been emitted from the canister. The canister system 

emissions that occur before the onset of breakthrough are bleed emissions. Target 

canister system emission levels for zero-evaporative vehicles are in the 0.003-0.010 

gram/test range. These bleed emissions occurring at this level are not due to lack of 

adsorptive capacity in the canister, but are due to diffusion (i.e., transfer of adsorbed 

fuel molecules through the canister to the port which is open to the atmosphere)

(Williams et al. 2001).

The majority of zero-evaporative vehicles incorporate a hydrocarbon scrubber in order 

to achieve very low level bleed emissions. Most often, the scrubber is an auxiliary 

activated carbon honeycomb attached to the canister’s atmosphere port. Simulated real 
Page 53

time two-day diurnal testing, at 150 bed volumes of purge, yielded emissions of 0.196 

grams with a standard canister, which were reduced to 0.015 grams with the addition of 

a hydrocarbon scrubber (Williams et al. 2001).

3.1.2. Fuel Storage and Delivery System

Fuel permeation through the fuel tank, fuel lines, and vapor lines, combined with 

leakage from the associated connections for these components, contribute to 

evaporative emissions. In the fuel systems of current zero-evaporative vehicles, both 

system configuration and materials selection are optimized to achieve minimal 

evaporative emissions.

A system that has a minimal number of connections and components exposed to the 

atmosphere will have fewer opportunities for leakage. One current design practice 

involves integrating components such as venting valves, the fuel filter, and the fuel 

pump inside the fuel tank. Some fuel tanks use a common entry port for these internal 

components. For sealing off exposed components and critical joints, such as the fuel 

tank inlet, some designs include an external barrier film application. 

Hydrocarbon permeation is reduced in current fuel system designs by minimizing the 

permeable materials’ fuel exposure area and incorporating low/no permeation materials. 

Steel and plastic are used for the rigid components of the fuel system. Gasoline and 

alcohol do not permeate steel, while with plastic, permeation does occur, but this is 

drastically reduced by adding barrier layer(s) composed of low permeation materials. 

Rigid component barrier layer materials such as ethylene vinyl alcohol (EVOH) and 

fluoropolymers have shown good performance in limiting permeation with ethanolcontaining fuels (Nulman et al. 2001). For seal, gasket, and hose applications, 

fluoroelastomers have been shown to limit permeation from ethanol containing fuels 

while retaining the mechanical properties required for a robust seal (Thomas et al. 

2009).

Staff expects that the proposed test fuel containing 10 percent ethanol would result in a 

small increase in evaporative emissions during certification testing in comparison to 

certification tests conducted using the current MTBE-based fuel with no ethanol. The 

expected increase in certification emissions would be due to increased permeation, 

which can increase fuel system hydrocarbon emissions by as much as 0.028 grams on 

a zero-evaporative passenger car (Haskew et al. 2006). However, most vehicles 

currently contain low-permeation materials because manufacturers must design for the 

commercial fuel in California, which contains up to 10 percent ethanol. Therefore, staff 

does not expect manufacturers to make significant changes to the fuel system to 

accommodate the proposed test fuel, nor does staff expect any impact on fleet 

evaporative emissions due to the change.
Page 54

3.1.3. Air Intake System Evaporative Controls

The vehicle’s air intake system (AIS) is another channel from which evaporative 

emissions can escape. These emissions result when fuel injector leakage, vapors from 

uncombusted fuel in the intake manifold, and crankcase blow-by gases escape out of 

the vehicle’s AIS. AIS emissions occur when the engine is turned off and the engine 

compartment is exposed to residual engine heat in addition to heat from diurnal 

temperature variations. The majority of current zero-evaporative vehicles are equipped 

with some form of AIS emission control element. Non-zero-evaporative vehicles are 

typically certified without an AIS element.

An AIS control element is typically placed in either the vehicle’s airbox or in the air tube 

between the throttle body and the airbox. The AIS element adsorbs hydrocarbon 

vapors that pass by or through it by the means of an activated carbon or synthetic 

Zeolite material. Similar to the carbon canister’s functionality, when the engine is 

operated, the hydrocarbons adsorbed on the AIS element are drawn into the engine for 

combustion. These devices are designed to be permanently installed and maintain their 

function for the vehicle’s full useful life.

3.2. Potential Technologies for Compliance with Proposed Standards

Staff expects that the fuel system and evaporative control technology package required 

for a vehicle to meet the proposed standards would be equivalent to what is in today’s 

zero-evaporative vehicle. However, hybrid vehicles could require some additional 

technology to meet the proposed bleed emission test standard, because they have less 

available purge to regenerate the carbon canister. Since the internal combustion 

engine in a hybrid may be turned off for long periods during vehicle operation, there are 

fewer opportunities to purge the canister. Purge volume is normally expressed in terms 

of canister bed volumes displaced during the two-day test procedure. Currently, a nonhybrid zero-evaporative vehicle yields 150-250 bed volumes while, in contrast, a hybrid 

with an integrated evaporative system produces 70-100 bed volumes. A trend of 

decreasing available purge is expected for future hybrid vehicles, due to increased time 

in engine-off mode.

A partially pressurized fuel tank is expected to be one of the most feasible technologies 

to compensate for hybrid vehicles’ lower available purge. Since the fuel tank would be 

sealed up to a particular threshold pressure, this technology would facilitate reduced 

canister loading. Heated purge may be another option for addressing low-purge by 

increasing the efficiency of a given purge volume.
Page 55

4. COST ANALYSIS

4.1. Cost methodology

Staff has estimated the cost to auto manufacturers to implement the proposed changes 

to the evaporative emission program. Cost information was obtained by consulting with 

fuel system suppliers, vehicle manufacturers, and USEPA. A typical vehicle meeting 

the current LEV II evaporative standards was used as the baseline for determining 

incremental costs.

4.2. Cost Analysis

Table II-B-4-1 shows an estimate of the added cost per vehicle for various parts of the 

fuel and evaporative control system to meet the proposed standards. The majority of 

the costs are expected to be due to the expansion of existing zero-evaporative 

technology. Some manufacturers have already integrated zero-evaporative 

components to a large extent on the rest of their fleet, which should reduce their 

compliance costs. The cost values noted below have been weighted based upon the 

fact that it takes a combination of the modifications listed below, not necessarily all of 

them, to achieve a zero-evaporative system. Four dollars of indirect costs were added 

to account for overhead as well as fixed (one time) costs that would be incurred in a 

small proportion of cases requiring a new component design for an in-house 

manufactured part, such as a fuel tank. Staff does not expect there to be a substantial 

difference in incremental cost among the various vehicle weight categories. The 

heavier vehicles would require more materials, but this should balance out cost-wise 

since the additional space allows for a more simple design and layout of fuel system 

components.

Table II-B-4-1. Evaporative Technologies’ Incremental cost

Component Changes Added cost per vehicle

Fuel tank

Minimize ports (locate vents and valves 

inside tank, entry through a common 

port), low permeation material, vapor 

block valve for hybrids

$2.90

Canister Addition of hydrocarbon scrubber $10.00

AIS System Addition of control element $2.00

Fuel lines and system 

connections

Fewer components, low permeation 

material $2.10

Total direct 

manufacturing costs $17

Total + $4.00 indirect 

costs $21
Page 56

5. OUTSTANDING ISSUES

During the development of the evaporative emission proposal, staff deliberated with 

affected vehicle manufacturers on various issues related to the rulemaking. In addition, 

staff held several rulemaking workshops for the general public to solicit feedback on the 

proposal. Although most of the rulemaking issues have been resolved, there is one 

remaining issue that is still under consideration. This issue pertains to vehicle 

evaporative emissions as measured in the field. A recent USEPA test program showed 

that for many vehicles, in-use evaporative emissions are much higher than those 

observed during certification, indicating the need to strengthen current certification and 

in-use compliance programs. Although test data on current zero-evaporative emission 

vehicles (i.e., PZEVs) are limited, it is expected that the materials and connections used 

to meet the proposed LEV III evaporative emission requirements will reduce emissions 

over the lifetime of the vehicle, in part by reducing in-use deterioration. Current onboard diagnostic (OBD) systems also monitor for evaporative system leaks, although 

not all leaks may be detected and the onus is on the vehicle owner to have the leak 

repaired. Thus, if even a small percentage of vehicles develop leaks in-use, significant 

gains from LEV III could be lost. As such, ARB staff is working with EPA to develop a 

leak emission standard and test procedure. A requirement that vehicles be subject to a 

“leak test” requirement both at certification and in-use could be incorporated into LEV III 

when the currently proposed rule is finalized or, more likely, through a separate 

rulemaking in the future. Because fuel system leaks develop as vehicles age and new 

systems are unlikely to fail the leak test as proposed, it is anticipated that manufacturers 

would be given the option to provide an attestation of compliance at certification, with 

compliance testing conducted primarily during the in-use verification program. 

Although ARB, USEPA, and industry are still working on the details of the leak test, a 

general outline of the procedure is provided in Figure II-B-5-1. The leak test would 

utilize a test apparatus that would attach to the vehicle fuel system, either through a 

dedicated test port or through a fuel system opening such as the filler pipe. The fuel 

system would then be sealed and slightly pressurized (less than 0.5 pounds per square 

inch) with an inert gas. The test apparatus would be calibrated such that at a given 

temperature and system pressure, the flow of gas through the apparatus corresponds to 

the leak size. For example, a larger leak in the fuel system would be correlated with a 

higher flow rate through the apparatus due to the need for more inert gas to maintain a 

given pressure as gas is lost through the leak(s). It is expected that the certification and 

in-use standards for maximum permissible orifice size will be set between 0.01 and 0.02 

inches. Staff anticipates that manufacturers would be able to conduct this test either in 

sequence with the current 2-day or 3-day diurnal test procedure or as a stand-alone test 

procedure utilizing the same preconditioning procedures as the diurnal tests. This 

requirement would complement the OBD evaporative system leak monitoring 

requirement, not replace it.
Page 57

Calibrate and/or verify testing apparatus

Precondition vehicle similar to diurnal test 

(fuel to 40%, soak 6 hours)

Seal fuel system so as to pressure test entire 

system (purge valve, cap, etc.)

Attach tester to vehicle’s fuel system

Pressurize fuel system with inert gas (max 0.5 psi)

Allow flow and pressure to stabilize

Determine effective leak size from output data

Calculated effective leak size must be less than 

0.01 - 0.02 inches

Figure II-B-5-1. Flow chart depicting the outlined procedure for the proposed leak test.

While detailed regulatory text for the leak test requirement is not currently proposed as 

part of the LEV III evaporative emissions program, staff proposes that the LEV III/GHG 

regulatory proposal, as part of the Advanced Clean Cars rulemaking package, be 

finalized with the final federal leak test and standard as described, provided it is 

substantially similar to that depicted in Figure II-B-5-1. ARB staff anticipates that 

USEPA will incorporate the leak test and associated standards when the Tier 3 

rulemaking is finalized in 2012, at which time ARB staff will evaluate whether this test 

requirement should be included into LEV III for certification and in-use verification 
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purposes. Assuming staff determines that the leak test and standard are appropriate for 

inclusion into LEV III, the finalized federal regulatory language, as modified by 

California, would be subject to additional public comment – ideally occurring before ARB 

has finalized the current rule – in order to promote harmonization within the national 

program. 

6. REGULATORY ALTERNATIVES TO EVAPORATIVE EMISSION PROPOSAL

As part of the regulatory development process, the following alternatives to this 

proposal were considered.

6.1. Do Not Amend the Evaporative Emission Standards

To continue to reduce smog-forming VOC emissions, staff believes it is necessary to 

increase the stringency of the current evaporative standards. Based on staff’s 

analyses, the proposed regulation is feasible and cost-effective since for the most part, 

it would require only expansion of existing zero-evaporative technology.

6.2. Adopt More Stringent Evaporative Emission Standards

6.2.1. Zero-fuel test requirement

Extending the zero fuel, or rig test, to the entire fleet was seen as a way to reduce 

evaporative emissions. However, manufacturers contend that this test is excessively 

burdensome due to the complexity and cost of setting up fuel system rigs, and the new 

test facilities that would be required. Option 2, with the lower whole vehicle standard 

and the canister bleed test, has been proposed to give manufacturers an alternative to 

the rig test. Staff considers Option 2 to provide equivalent emission control as 

compared to the higher whole vehicle standard and rig test which make up the current 

zero-evaporative requirement. This rig test will be an option for manufacturers, as it is 

contained in the proposed Option 1.

6.2.2. Lower whole vehicle emission standard

Staff believes that the fuel systems on vehicles certified to the zero-evaporative 

emission standard represent the best of currently available evaporative control 

technology. A large proportion of the evaporative emissions on zero-evaporative 

certified vehicles come from non-fuel sources. Although there are current zeroevaporative vehicles with two-day and three-day diurnal plus hot soak certification levels 

below 0.150 grams, these vehicles have very low background (non-fuel) emissions, 

which staff believes would be very difficult to achieve on an average fleet-wide basis. 

Based upon a review of average zero-evaporative vehicle certification values, staff 

believes that the proposed emission standards are appropriate to expand the use of 

zero-evaporative technology to the rest of the fleet, and that a lower whole vehicle 

emission standard would not allow sufficient margin for non-fuel evaporative emissions.
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C. VEHICLE LABELING REQUIREMENTS

1. BACKGROUND

Since 1995, California’s Smog Index Label helped consumers assess the relative smog 

emissions from new cars. In 2005 Assembly Bill 1229 was signed into law (Nation, 

Chap. 75, Stats. 2005, codified at Health and Safety Code §43200.1). These 

amendments to California’s vehicle labeling regulations created a more user-friendly 

scoring system for determining the Smog Score and added a Global Warming Score. 

Both scores are based on a scale of 1 -10 with 10 being the cleanest and 5 representing 

an average new car.

The California Environmental Performance Label (Figure II-D-1-1) is required on all new 

vehicles sold in California that were manufactured after January 1, 2009. 

Figure II-D-1-1. California Environmental Performance Label

Per the Energy Independence and Security Act of 2007, the United States Department 

of Transportation, United States Department of Energy and USEPA were directed to 

revise the Federal Fuel Economy Label to reflect an automobile’s fuel economy and 

greenhouse gas and other emissions over the useful life of the automobile. It also 

required the revised label to include a rating system that would make it easy for 

consumers to compare the fuel economy and greenhouse gas and other emissions at 

the point of purchase.

Starting in the Spring of 2010, ARB staff began working with USEPA and NHTSA on 

revisions to the Fuel Economy Label. The goal of working with USEPA and NHTSA 

was to provide input on the information needed on the Federal label to allow California 

to use this Label in lieu of the California Environmental Performance label.
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Important California requirements addressed by the federal label included:

• Adding the following statement to the label: “Vehicle emissions are a significant 

cause of climate change and smog”

• Having a clear statement about upstream emissions and having a clear place to 

find this information on a regional basis.

• Including all cars in the rating system rather than segregating by size or class. 

Because of this successful collaboration California is able to harmonize with the federal 

labeling requirements. 

In June 2011, USEPA and NHTSA published 40 CFR Parts 85, 86, and 600 providing 

requirements for the new Fuel Economy and Environment Label meeting these 

requirements. This new Federal Label (Figure II-D-1-2) is required on all new cars 

starting with Model Year 2013 and can be affixed earlier on a voluntary basis. The new 

Federal Fuel Economy and Environment Label is a redesign that now includes a 

Greenhouse Gas and Fuel Economy Rating from 1 to 10 with 10 being best and a 

Smog Rating, also from 1 to 10 with 10 being cleanest. The content and graphical 

design are sufficiently similar to and were inspired by the Global Warming and Smog 

Scores on California’s Environmental Performance Label.

Figure II-D-1-2. Federal Fuel Economy and Environment Label, June 6, 2011
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2. SUMMARY OF PROPOSED REGULATION

Staff is proposing to add language to the “California Smog Index Label Specifications 

for 2009 and Subsequent Model Year Passenger Cars, Light-Duty Trucks, and MediumDuty Passenger Vehicles,” incorporated by reference at Title 13, California Code of 

Regulations, Section 1965), that would deem manufacturer compliance with the 

Federal Fuel Economy and Environment Label published in 40 CFR Parts 85, 86, and 

600 as promulgated on July 6, 2011 as compliant with the California Environmental 

Performance Label requirements. Providing consumers with only one label that 

includes substantial environmental information meeting California’s statutory 

requirements will avoid confusion as well as information overload. 

Staff is also proposing to add clarifying language about Neighborhood Electric Vehicles 

(NEVs). NEVs are not permitted to affix the Federal Fuel Economy and Environment 

Label because only those vehicles that qualify for Corporate Average Fuel Economy 

(CAFE) credits are permitted to have these labels. Since NEVs cannot receive these 

credits, they cannot affix this label. Therefore, for consistency, staff proposes to no 

longer require the Environmental Performance Label on these types of vehicles. 

3. COST ANALYSIS

By allowing OEMs to use the new Federal Fuel Economy and Environment to meet the 

California’s vehicle labeling requirements, OEMs will save money by not having to also 

print and affix the California Environmental Performance Label.

According to the May 4, 2007 Initial Statement of Reasons for the Environmental 

Performance Label, the initial annualized cost for compliance for the industry as a whole 

with these requirements was estimated to be $3,500 and the annual ongoing cost for a 

typical manufacturer was estimated to be $4,667, making an OEM’s total annual cost for 

printing the California Environmental Performance Label and affixing it to all of their cars 

to be $8,167. Although the initial annualized costs will not change, the ongoing annual 

cost will go to zero.

D. MINOR AMENDMENTS TO THE ON-BOARD DIAGNOSTICS REGULATIONS

1. BACKGROUND

Second generation on-board diagnostics (OBD II) systems are comprised mainly of 

software designed into the vehicle’s on-board computer to detect emission control 

system malfunctions as they occur by monitoring virtually every component and system 

that can cause an increase in emissions. When an emission-related malfunction is 

detected, the OBD II system alerts the vehicle owner by illuminating the malfunction 

indicator light (MIL) on the instrument panel. By alerting the owner of malfunctions as 

they occur, repairs can be sought promptly, which results in fewer emissions from the 

vehicle. Additionally, the OBD II system stores important information including 

identification of the faulty component or system and the nature of the fault, which would 
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allow for quick diagnosis and proper repair of the problem by technicians. This helps 

owners achieve less expensive repairs and promotes repairs done correctly the first 

time.

With OBD II systems having been required on all 1996 and newer vehicles produced for 

sale in California and most vehicles sold nationwide, more than 110 million vehicles are 

currently equipped with them. Input from manufacturers, service technicians, inspection 

and maintenance (I/M) programs, and in-use evaluation programs indicate that OBD II 

systems are very effective in finding emission problems and facilitating repairs. 

Accordingly, US EPA issued a final rule indicating its confidence in the performance of 

OBD II systems by requiring states with I/M programs to perform OBD II checks for 

these newer cars and allowing them to be used in lieu of current tailpipe tests. The 

California I/M program (Smog Check) has adopted these provisions.

The California Air Resources Board (ARB) originally adopted the light- and medium-duty 

vehicle OBD II regulation in 1989 for the 1994 and newer model years. As directed by 

the Board, the regulation has been reviewed and updated at regular updates since then, 

with the last major update to the regulation occurring in 2006 as well as updates to the 

medium-duty diesel requirements occurring in 2009. Staff was not scheduled to go to 

the Board this year to update the OBD II regulation; however, manufacturers recently 

approached ARB staff and requested regulation changes that they indicated were 

needed immediately in order to ensure compliance when they certify their 2013 model 

year vehicles. Manufacturers and ARB staff held discussions with interested 

manufacturers, including a face-to-face meeting on July 27, 2011, to discuss their 

proposal. 

In response to the manufacturers’ requests, staff is proposing changes to the OBD II 

regulation, California Code of Regulations (Cal. Code Regs.), title 13, section 1968.2, 

and its associated enforcement regulation, section 1968.5. 

2. SUMMARY OF PROPOSED AMENDMENTS

Section 1968.2(c): Definitions 

The OBD II regulation currently defines “calculated load value” for diesels as 

“determined by the ratio of current output torque to maximum output torque at current 

engine speed as defined by suspect parameter number (SPN) 92 of SAE J1939.” 

Manufacturers have indicated that the definition in Society of Automotive Engineers 

(SAE) J1939 only applies to heavy-duty diesel engines, so they need a comparable 

definition that would apply to light- duty and medium-duty diesel vehicles. Thus, ARB 

staff is proposing to modify the language to allow manufacturers to use the definition of 

“calculated load value” that was recently amended in SAE J1979 for diesel vehicles. 

The OBD II regulation currently allows manufacturers to erase a confirmed fault code if 

the identified malfunction has not been again detected in at least 40 engine warm-up 

cycles and the MIL is presently not illuminated for that malfunction. The regulation 
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currently defines “warm-up cycle” as “sufficient vehicle operation such that the coolant 

temperature has risen by at least 40 degrees Fahrenheit from engine starting and 

reaches a minimum temperature of at least 160 degrees Fahrenheit (140 degrees 

Fahrenheit for applications with diesel engines).” Manufacturers have expressed 

concern that certain vehicles such as hybrid vehicles or vehicles with highly efficient 

engines may not be able to meet these temperature criteria under normal driving and 

ambient conditions. Thus, manufacturers have requested language that allows 

manufacturers to use an alternate minimum temperature criterion. Staff understands 

that some allowances should be made for such vehicles that are unable to warm-up the 

engine coolant temperature to the defined temperatures even if it has been sufficiently 

driven. Thus, staff is proposing to allow manufacturers the option to define a “warm-up 

cycle” as a driving cycle in which the criteria to erase a permanent fault code for 

continuous monitors are met (sections 1968.2(d)(2.5.2)(B)(iii)a., b. and c.). This would 

ensure that the vehicle has been operated for a sufficient period of time to reasonably 

detect a recurrence of the malfunction but does not delay erasure of confirmed fault 

codes. 

Staff is proposing changes to the permanent fault code erasure requirements and the 

in-use monitor performance requirements that would apply to hybrid vehicles, details of 

which are described below. Given the context of the proposed changes, new definitions 

would be needed to complement the proposed requirements. Thus, staff is also 

proposing four new definitions for “hybrid vehicle,” “plug-in hybrid electric vehicle,” 

“fueled engine operation,” and “propulsion system active” to supplement the proposed 

changes. More details about the proposed definitions can be found below.

Section 1968.2(d)(2.5): Erasing a Permanent Fault Code

The OBD II regulation requires the OBD II system to store a “permanent” fault code for 

an emission-related fault in non-volatile memory that can only be erased if the monitor 

responsible for setting that fault code has run and passed enough times to confirm that 

the fault is no longer present. Currently, the regulatory language (section 

1968.2(d)(2.5.1)) states that the permanent fault code can be erased “only if the OBD II 

system itself determines that the malfunction that caused the permanent fault code to 

be stored is no longer present and is not commanding the MIL on, pursuant to the 

requirements of section (d)(2.3) (which for purposes of this section shall apply to all 

monitors).” Manufacturers have expressed confusion about the exact timing of erasing 

the permanent fault code. Thus, staff is proposing to clarify the requirement by adding 

language indicating that erasure of the permanent fault code shall occur in conjunction 

with extinguishing the MIL or no later than the start of the first driving cycle that begins 

with the MIL commanded off.

Additionally, staff is proposing changes to address issues concerning permanent fault 

code erasure on hybrid vehicles for monitors that are designed to run continuously, 

including monitors that must wait until similar conditions are satisfied (e.g., gasoline 

misfire and fuel system monitors). Currently, the regulation requires that the permanent 

fault code for these monitors be erased only after the vehicle has been operated such 
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that, among other conditions, criteria similar to those for a general denominator (section 

1968.2(d)(4.3.2)(B)) have been satisfied on a single driving cycle (with the exception 

that the general denominator conditions require ambient temperature above 20 degrees 

Fahrenheit or below 8000 feet in elevation). This ensures that the vehicle has been 

operated for a sufficient period of time to reasonably detect a recurrence of the 

malfunction but does not unnecessarily delay erasure of the permanent fault code. 

Among these conditions is the criterion that the “cumulative time since engine start” be 

greater than or equal to 600 seconds. Manufacturers have indicated that changes are 

needed to account for the fact that hybrid vehicles, especially plug-in hybrids, may 

encounter a significant number of driving cycles where the engine starts very late (if at 

all) in a typical drive cycle and the cumulative amount of engine runtime is limited. 

Thus, for hybrid vehicles, staff is proposing to clarify that manufacturers should use 600 

cumulative seconds of “propulsion system active” time in lieu of the 600 cumulative 

seconds after engine start, with “propulsion system active” defined as when the vehicle 

is operated, regardless of whether it is powered by the battery or the engine or both. 

Staff believes this new definition would ensure equivalent vehicle operation time 

between conventional vehicles and hybrid vehicles. Further, the new language is 

consistent with how manufacturers have been implementing such counters to date on 

hybrid vehicles but the clarifications will provide more guidance especially to those that 

have not yet certified hybrid vehicles.

Sections 1968.2(d)(3.2), (d)(4.3.2), and (d)(5.5) and Section 1968.5: In-Use Monitor 

Performance Specifications

The OBD II regulation requires manufacturers to track monitor performance by counting 

the number of monitoring events and the number of driving events. The number of 

monitoring events is defined as the numerator and the number of driving events is 

defined as the denominator. The ratio of these two numbers is referred to as the 

monitoring frequency and provides an indication of how often the monitor is operating 

relative to vehicle operation. The regulation also requires all vehicles to keep track of a 

“general denominator”, which is a measure of how often the vehicle is operated. The 

regulation requires manufacturer to increment this denominator only if certain criteria 

are satisfied on a single driving cycle. This method allows very short trips or trips during 

extreme conditions such as very cold temperatures or very high altitude to be filtered 

out and excluded from the count. This is appropriate because these are also conditions 

where most OBD II monitors are neither expected nor required to operate. 

The regulation currently requires all vehicles to increment the general denominator if, 

among other conditions, the “cumulative time since engine start” is greater than or equal 

to 600 seconds. For the same reasons noted above, hybrid vehicles, especially plug-in 

hybrids, need an alternate definition to recognize trips where the engine does not start 

or starts much later in the trip. Manufacturers are concerned that with the current 

regulatory language, the general denominator will increment more often than it should 

compared to how often the monitors will have had a chance to run in-use (i.e., how long 

the engine will actually be turned on) and are concerned that the resulting ratios will not 

be able to meet the minimum required ratios. They further argued that this may force 
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them to increase engine operation just to run the monitors to meet the required ratios, 

which would reduce vehicle efficiency and basically reduce the advantages of the plugin capability. Staff agrees that some changes are needed to account for these issues. 

Thus, similar to the changes proposed above for the permanent fault code erasure 

protocol, for hybrid vehicles, staff is proposing to clarify that manufacturers must use 

600 cumulative seconds of “propulsion system active” time in lieu of the 600 cumulative 

seconds after engine start when incrementing the general denominator. Additionally, 

staff is also proposing to require 10 seconds of “fueled engine operation” to be met in 

order to increment the general denominator to discern between trips with and without 

engine operation. This condition would ensure that only trips where the engine has at 

least turned on once during the driving cycle are counted when looking at how often 

engine-related emission control component monitors are running. These proposed 

changes would apply to 2014 and subsequent model year hybrid vehicles.

Additionally, manufacturers indicated changes are needed to the denominator 

incrementing criteria for evaporative system monitors. Unlike tailpipe emissions where 

the engine has to operate in order for emissions to occur, evaporative emissions such 

as gasoline vapor escaping from the gasoline tank to the atmosphere can occur from a 

vehicle while it is parked or being operated off of battery power. Accordingly, the 

evaporative system monitors need to work, regardless of how often the engine is 

actually started or used on the vehicle. The regulation currently requires the 

evaporative system monitor denominator to be incremented only on trips that meet a 

‘cold start’ definition (i.e., if the engine coolant temperature (ECT) and the ambient 

temperature are considered cold and the ECT at engine start is less than or equal to 

12 degrees Fahrenheit higher than ambient temperature at start). The criteria were set 

to ensure that the vehicle has had a long enough soak period such that the evaporative 

system (fuel tank, canister, etc.) will have cooled down and stabilized by the beginning 

of the driving cycle and it would be technically feasible to run a robust evaporative 

system monitor. 

While this current ‘cold start’ definition works adequately for conventional vehicles and 

traditional hybrids, manufacturers have argued that plug-in hybrid electric vehicles will 

have some driving cycles that are all-electric and that the definition does not address 

such conditions. Specifically, the existing definition could result in multiple increments 

of the evaporative system monitor denominator after short all-electric drive trips even 

though the evaporative system is no longer at a stabilized condition because ECT will 

still be within the cold start-defined window relative to ambient temperature. Staff 

agrees that changes are needed to avoid these issues and is proposing alternative 

criteria for plug-in electric hybrid vehicles that would better ensure a long soak period 

similar to that on conventional vehicles and traditional hybrids. Specifically, for 2015 

and subsequent model year plug-in hybrid electric vehicles, staff is proposing that the 

denominator be incremented when the soak period immediately preceding the driving 

cycle is greater than or equal to 6 hours in lieu of requiring the ECT at engine start to be 

less than or equal to 12 degrees Fahrenheit higher than ambient temperature at start. 

For example, a conventional car would first look at ECT and ambient temperature at 

engine start, make sure they agree with each other to confirm it is a cold start of the 
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vehicle, make sure ambient temperature is within acceptable ranges, and then look for 

the drive cycle to meet the rest of the criteria to count as an evaporative system 

denominator trip. Plug-in hybrids, however, would instead first look at the amount of 

time the vehicle has been off/not operated when the vehicle is first started, make sure 

that it has been at least 6 hours since the previous vehicle trip to confirm it is a cold start 

of the vehicle, and then make sure the ambient temperature is within range and that the 

drive cycle meets the rest of the criteria to count as an evaporative system denominator 

trip. For additional flexibility to manufacturers, plug-in hybrid electric vehicles built prior 

to the 2015 model year would have the option of using these new criteria or the existing 

criteria to increment the evaporative system monitor denominator.

Manufacturers have also argued that a smaller minimum required ratio is needed to 

account for the limited engine operation time for plug-in hybrid vehicles and to allow 

them to maximize electric operation/minimize CO2 emissions. While staff believes 

some relief is needed with respect to the ratio, staff believes a smaller ratio is only 

needed for the interim years considering the proposed revisions to the denominator 

criteria above would already provide substantial relief in meeting the in-use performance 

ratio requirements relative to conventional vehicles. Thus, staff is proposing that for 

monitors of components or systems that require engine operation on plug-in hybrid 

electric vehicles, manufacturers would be required to meet a minimum ratio of 0.100 in 

lieu of the current higher ratios (e.g., 0.336 for most monitors) through the 2016 model 

year. This would allow manufacturers to run monitors less frequently on plug-in hybrids 

and still be considered compliant. Starting with the 2017 model year, the interim relief 

would end and these monitors would be required to meet the higher minimum ratios 

currently required in the regulation. However, staff will also plan to revisit this 

requirement once plug-in hybrid electric vehicles are in-use and data are available to 

better strike a balance between monitoring frequency (to detect emission faults in a 

timely manner) and reduced engine operation (and the resultant CO2 emissions). Staff 

is also accordingly proposing changes in the OBD II enforcement regulation (Cal. Code 

Regs., title 13 section 1968.5) to account for the newly proposed ratio when determining 

OBD II non-compliances for plug-in hybrid electric vehicles.

Lastly, staff is proposing changes to the ignition cycle counter requirements for hybrid 

vehicles and plug-in hybrid electric vehicles. Currently, manufacturers are required to 

track and report an ignition cycle counter, which is required to be incremented every 

time the vehicle is started (i.e., “engine start” is met). This is basically a counter of the 

number of driving cycles experienced by the vehicle. First, staff is proposing to modify 

the incrementing criteria for hybrid vehicles – specifically, staff is proposing to clarify 

that manufacturers increment the ignition cycle counter when the “propulsion system 

active” definition is met (e.g., each time the vehicle is operated, without respect to 

whether the engine is started or used). This is consistent with how hybrid 

manufacturers have been tracking this counter to date. Second, staff is proposing that 

2014 and subsequent model year plug-in hybrid electric vehicles track and report an 

additional, separate ignition cycle counter that would be incremented when the “fueled 

engine operation” definition has been met (e.g., each time the vehicle is operated and 

the engine is started at least once). These data would provide valuable information 
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about how often all-electric driving cycles occur in-use for plug-in hybrid electric 

vehicles, which would help staff determine if further changes are needed to the in-use 

monitor performance requirements, including the required minimum acceptable in-use 

performance ratios, for these vehicles. 

Staff is also proposing changes to the denominator incrementing criteria for particulate 

matter (PM) sensor and PM sensor heater monitors. These proposed changes are 

discussed in more detail below in the “Diesel PM Filter Monitoring” section.

Section 1968.2(e)(3.3): Gasoline Misfire Monitoring 

The OBD II regulation currently requires manufacturers to continuously monitor for 

misfire faults from no later than the end of the second crankshaft revolution after engine 

start. The language, however, does not specifically address engines that employ 

engine shutoff strategies (e.g., hybrid vehicles that shut off the engine at idle) and can 

restart the engine multiple times within the same driving cycle. Additionally, the term 

“engine start” is currently being used in the OBD II regulation for many requirements 

with the intent that “engine start” signifies the start of vehicle operation, which may or 

may not involve the engine actually being started in a hybrid vehicle. Since more time is 

needed to determine appropriate industry-wide conditions to require misfire monitoring 

after the engine is first started and subsequently restarted, staff is, in the meantime 

proposing to require manufacturers to propose their own conditions for ARB approval. 

As with other similar items in the regulation, the criteria that ARB will use to approve 

such requests are identified in the regulation and, in this specific case, are primarily 

based on the equivalence of the manufacturer-proposed conditions compared to the 

current requirements to enable as soon as technically possible, which is typically within 

two crankshaft revolutions of engine starting. 

Section 1968.2(f)(1.2.3)(B): Diesel Non-Methane Hydrocarbon (NMHC) Converting 

Catalyst Monitoring

The OBD II regulation requires manufacturers to monitor the NMHC catalyst for its 

NMHC conversion capability and for its ability to perform other emission-related 

functions. One such function is the ability of the catalyst to generate a desired feedgas 

(e.g., nitrogen dioxide (NO2)) to promote better performance in a downstream 

aftertreatment component (e.g., for higher NOx conversion efficiency in a selective 

catalytic reduction (SCR) system). Currently, the regulation requires 2010 and 

subsequent model year light-duty vehicles and 2013 and subsequent model year 

medium-duty vehicles to meet this requirement. Manufacturers have asked ARB to 

delay the start date to meet this requirement in part because their original plans to 

comply were based on using monitors for the NMHC conversion efficiency of the NMHC 

catalyst and/or NOx conversion efficiency of the SCR system and such approaches 

were not uniformly successful. This resulted in manufacturers having to investigate 

alternative monitoring strategies and consequently indicating they need more time to 

verify these strategies. While staff believes it is feasible to develop a monitor to meet 

this requirement, staff acknowledges that more time is needed to develop a robust 
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monitor to meet this requirement. Thus, staff is proposing to delay monitoring of proper 

feedgas generation until the 2015 model year for light-duty and medium-duty vehicles. 

Considering this proposed delay is for a secondary function of the NMHC catalyst, staff 

determined this delay would not result in any lost emission benefits. 

Sections 1968.2(d)(4.3.2), (f)(9.2.4), (f)(17.1), and (k): Diesel PM Filter Monitoring

The OBD II regulation currently requires the OBD II system to identify malfunctions of 

the PM filter when the filtering capability degrades to a level such that tailpipe emissions 

exceed a specific threshold. For 2013 and subsequent model year light-duty vehicles, 

the threshold is 1.75 times the applicable standards, and for 2013 and subsequent 

model year medium-duty vehicles, the PM threshold is 0.03 g/bhp-hr (approximately 

3 times the applicable standards). Manufacturers have expressed concern that the 

thresholds are too stringent and not technically feasible for the 2013 model year time 

frame, contending that the current status of technology (e.g., the usage of differential 

pressure sensors) cannot support such thresholds. 

In order to achieve the thresholds, manufacturers believe PM sensors are necessary, 

and while PM sensor suppliers have been rapidly developing and refining their products, 

only some of the vehicle and engine manufacturers are able to introduce such sensors 

on their 2013 model year products. In some cases, the manufacturers have indicated 

that the sensor suppliers have selected only certain manufacturers to work with on a 

limited introduction to continue to test out the sensor before wide-scale implementation, 

while others have indicated that they have run into issues that need to be resolved by 

both them and the supplier before the sensors are production ready. Thus, 

manufacturers have asked ARB to delay the start date of the 2013 thresholds of 1.75 

times the standards to a later model year. 

ARB staff agrees that PM sensors do not appear to be available to meet wide-scale 

demand in 2013 and understands that relief is needed based on discussions with 

manufacturers about their progress in meeting the monitoring requirements. However, 

staff believes more discussions are needed to determine when the appropriate start 

date should be. In the meantime, staff is proposing to allow light-duty and medium-duty 

diesel manufacturers that do not successfully introduce a PM sensor in the 2013 model 

year to extend the deficiency allowance for the PM filter performance monitor so that all 

2013 model year products can be certified (albeit with a deficiency). Concurrently, staff 

is proposing necessary associated changes to extend the allowance to exclude 

detection of specific failure modes for PM filter monitoring (section (f)(17.1)) through the 

2013 model year. This allowance recognizes one of the issues that monitoring 

techniques that do not use a PM sensor may have with respect to detecting failures 

such as a partially melted and partially cracked substrate that theoretically have 

offsetting impacts on the detectable parameter (e.g., differential pressure across the 

filter). Considering the delay is only one additional year, staff determined this delay 

would not result in any lost emission benefits. 
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Additionally, staff is proposing amendments that would apply to those manufacturers 

that do implement PM sensors on their 2013 and/or 2014 model year vehicles. The 

OBD II requirements are often technology forcing and PM filter monitoring is definitely 

one such requirement. Many believe that PM sensors will be the only viable way to 

meet the final monitoring thresholds and staff wants to continue to encourage those 

manufacturers that aggressively push forward to implement such technologies. 

Considering these sensors are new technology that haven’t been used in the field, 

some of the manufacturers that are still on track to implement such technology for the 

2013 and/or 2014 model year expressed concern about meeting the regulation should 

something not work out as well as expected with the sensor. Specifically, 

manufacturers are worried about the PM filter monitor that the sensor is intended to be 

used for as well as monitoring of the sensor itself. Thus, manufacturers have indicated 

that they may not incorporate PM sensors if changes weren’t made to the regulation 

that would reduce the risks should something fall short, especially given the costs of 

being one of the first to incorporate such sensors. Accordingly, staff is proposing 

additional changes that would apply only to those that do implement a PM sensor in the 

2013 and/or 2014 model year to help achieve a balance that continues to encourage 

early implementation by removing some of the risk to manufacturers should something 

fall short of the current requirements. Specifically, for the 2013 and 2014 model years, 

staff is proposing to allow these light-duty and medium-duty diesel manufacturers to 

certify their vehicles with “free” deficiencies (i.e., deficiencies that would not be subject 

to fines) for the PM filter performance monitor and PM sensor and sensor heater 

monitors. Further, staff is also proposing amendments to the in-use monitor 

performance requirements for PM sensor and PM sensor heater monitors. The OBD II 

regulation currently requires the PM sensor monitoring capability monitor (section 

1968.2(f)(5.2.2)(D)) and the PM sensor heater monitor (section 1968.2(f)(5.2.4)(A)) to 

use the general denominator as the monitor denominators. PM sensors, like PM filters, 

may be regenerated infrequently in-use, which may make frequent monitoring difficult. 

Manufacturers are concerned that using the general denominator may result in the 

denominator incrementing more often than is appropriate for the sensor technology and 

how it is used. Thus, staff is proposing to allow manufacturers to propose alternate 

criteria (for ARB review and approval) to increment the denominator for PM sensor 

monitoring capability monitors. For PM sensor heater monitors, staff is proposing to 

require manufacturers to increment the denominator when, in addition to the general 

denominator criteria, the heater has been commanded to function on two or more 

occasions for greater than two seconds or for a cumulative time greater than or equal to 

ten seconds.

The OBD II regulation also requires manufacturers to monitor the NMHC conversion 

capability of catalyzed PM filters. Currently, the regulation requires 2010 and 

subsequent model year light-duty vehicles and 2013 and subsequent model year 

medium-duty vehicles to meet this requirement. Similar to the discussion above 

regarding monitoring a secondary function of NMHC converting catalysts (e.g., their 

ability to generate a proper feedgas for SCR catalysts), the catalyzed coating of a PM 

filter has secondary functions that have an emission impact. These functions can 

include promotion of passive regeneration at lower exhaust temperatures, conversion of 
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HC and carbon monoxide created during an active regeneration, and generation of NO2

feedgas for downstream SCR systems. Manufacturers, however, have argued that 

many of these functions are just side effects that directionally help, but are not 

necessary to comply with the emission standards. They further indicated that there are 

currently no suitable robust monitoring strategies available to discern the proper 

operation of these secondary functions. Thus, manufacturers have asked ARB to delay 

the start date to meet this requirement. 

As discussed in the 2009 HD OBD and OBD II Staff Report, ARB staff believes that 

such secondary functions are not trivial and warrant monitoring to ensure overall 

effectiveness of the emission control system. Staff proposed several possibilities for 

monitoring strategies in the last Staff Report and manufacturers have not investigated 

all of the possibilities for monitoring at this point. The success of the monitoring 

approaches may still be highly dependent on the actual catalyst configuration, 

significance of the catalyst loading on the PM filter, and regeneration strategy 

(especially reliance on high levels of passive regeneration) and thus require 

manufacturers to take OBD monitoring capability into consideration when designing and 

implementing the aftertreatment system and control strategy. However, recognizing 

that the OBD engineers have often been left out of the design process due to the rapid 

deployment of new technologies and increasingly stringent standards, staff is proposing 

to delay the monitoring requirements of the catalyst function of catalyzed PM filters until 

the 2015 model year for light-duty and medium-duty vehicles to give manufacturers 

more time to refine their systems, optimize regeneration strategies, and better 

investigate the impacts of the catalyzed PM filter. Given the minimal delay, the smaller 

impact of these secondary functions of the emission controls, and the continued 

presence of other monitors of these emission controls (albeit it not for these specific 

functions), staff determined this delay would not result in any lost emission benefits. 

Section 1968.2(f)(15.2.2)(F): Fuel Control System Component Monitoring 

The OBD II regulation currently requires manufacturers to monitor fuel control system 

components (e.g., injectors, fuel pumps) that have tolerance compensation features 

implemented in hardware or software during production or repair procedures on 2013 

and subsequent model year diesel vehicles. Examples of these include individually 

coded injector-to-injector tolerances and fuel pumps that use in-line resistors to correct 

differences in fuel pump volume output. Monitoring of the components would ensure 

that misassembled systems, erroneous programming, or incomplete repair procedures 

that result in incorrect adjustment being applied (and consequently, increases in 

emission levels) will be detected. Manufacturers, however, have questioned the need 

to monitor this feature and have expressed concern about meeting this requirement in 

the 2013 timeframe. Manufacturers have indicated they have been working hard on 

improvements to their fuel system adaptive strategies to fully compensate or learn out 

any errors that may occur due to mismatches in the injector and the programmed 

tolerance/adjustment. This would allow manufacturers to avoid adding new hardware, 

such as a communication chip in the injector that would automatically communicate its 

characteristics to the engine computer, and avoid other alternatives such as tighter 
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tolerances on the injectors to meet this requirement. However, most are not currently 

able to fully achieve this. In some cases, the improved strategies can learn out most, 

but not all, of the error; in other cases, the learning can take a substantially long time. 

Staff believes that more lead time is necessary for manufacturers to fully refine their 

strategies. Thus, staff is proposing to delay the monitoring requirement of this feature 

until the 2015 model year for light-duty and medium-duty diesel vehicles. Given the 

minimal delay and that manufacturers will continue to improve and implement the 

strategies even during the delay years, staff determined this delay would not result in 

any lost emission benefits.

Section 1968.2(g)(1): Reference Documents 

Staff is proposing amendments that would incorporate another reference SAE 

document. As is common practice with technical standards, industry periodically 

updates the standards to add specification or clarity. The current OBD II regulation 

incorporates the May 2007 version of SAE J1979 “E/E Diagnostic Test Modes”. The 

proposal would update the regulation to incorporate a newly published sub-document of 

SAE J1979, the October 2011 version of SAE J1979-DA “Digital Annex of E/E 

Diagnostic Test Modes”14. This document contains some clarifications and 

modifications to the standardized data that must be reported by OBD II systems and is 

needed to properly implement some of the proposed changes on 2013 and subsequent 

model year vehicles.

Section 1968.2(g)(4.2): Data Stream 

An important aspect of OBD II is the ability of technicians to access critical information 

from the on-board computer in order to diagnose and repair emission-related 

malfunctions. ARB believes there are certain emission critical components and systems 

for which electronic information access through the data link connection would provide 

invaluable assistance in properly repairing vehicles. The availability of real-time 

information would also greatly assist technicians in responding to driveability complaints 

because the vehicle could be operated under the problem conditions and the technician 

would be able to know how various sensors and systems were acting at that time. Fuel 

use complaints, loss of performance complaints, intermittent problems, and others could 

also be potentially addressed. 

The OBD II regulation currently defines a number of data parameters that 

manufacturers are required to report to generic scan tools, including some parameters 

(mostly diesel-related) that must be reported starting in the 2013 model year. While in 

virtually every case, staff worked with SAE to ensure that the applicable SAE standards 

are updated well before they become required, in this particular instance, one 

parameter went through recent revisions as the manufacturers got further clarification 

 14 For organizational purposes, the SAE J1979 document that previously contained both the text 

descriptions of how to implement standardized data and tables of the actual standardized data has been 

split into two subparts. The second of those, called the Digital Annex, has what was previously contained 

in the tables and is what is being updated and incorporated by reference here.
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on how the parameter would be used. Specifically, for the data stream parameter “type 

of fuel currently being used”, which is currently required on all 2013 and subsequent 

model year vehicles, the staff is proposing to delay the requirement until the 2015 model 

year to allow manufacturers time to implement the latest revisions of the format for this 

parameter and address interpretations by some manufacturers that this parameter was 

only required on flex fuel vehicles. 

Additionally, the current regulation mistakenly lists “PM sensor output” as being required 

starting in both the 2010 model year and the 2013 model year. Therefore, staff is 

proposing to delete the reference to “PM sensor output” under the 2013 and subsequent 

model year language (section 1968.2(g)(4.2.6)(B)).

3. COST ANALYSIS

Most of the proposed amendments would either relax or clarify the current requirements 

in the OBD II regulation. Thus, the technological feasibility of the proposed 

amendments has already been determined and discussed above and in the staff reports 

for the previous OBD II rulemakings. A few other proposed changes that would be 

considered new requirements would consist of only minor software changes and are 

both being requested by industry and consistent with how industry has been 

implementing or planning for implementation. 

Considering most of the proposed amendments are intended to either relax or clarify the 

current requirements, the proposed amendments are also not expected to add any 

additional cost to manufacturers. For proposed changes that would be considered new 

requirements, these changes would consist of only software changes, and staff is 

proposing enough lead time for manufacturers to meet these requirements. Further, 

specific to the proposed new requirement changes, the existing requirements cannot be 

implemented without software changes for plug-in hybrids, so manufacturers are not 

incurring any extra cost to make that change consistent with the proposed 

requirements. Thus, the costs associated with these changes are considered 

negligible. Accordingly, the proposed amendments are not expected to alter the 

previously calculated emissions benefits or cost effectiveness values. 
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III. CALIFORNIA'S LIGHT-DUTY GREENHOUSE GAS REGULATIONS

Section III reports on the ARB staff assessment of climate change science and the 

proposed regulations for reducing climate change-related impacts from light-duty 

vehicles. The section is organized as follows. Section A.1 presents an overview of the 

climate change science that has provided the basis for a broad suite of policies in 

California to mitigate the risks of anthropogenic climate change via the reduction of 

greenhouse gas (GHG) emissions from major sources in the State. The following 

sections describe the logic, technical basis, and regulatory details for the proposed 

GHG standards for light duty vehicles. Section A.2 provides some context for the 

proposed standards with respect to the federal standards; section A.3 summarizes the 

proposed regulations; section A.4 provides the technical feasibility basis for reducing 

light-duty vehicle GHG emissions; and section A.5 describes the proposed GHG 

standards. 

A. PROPOSED AMENDMENTS TO CALIFORNIA'S LIGHT-DUTY GREENHOUSE 

GAS EMISSION STANDARDS 

1. CLIMATE CHANGE OVERVIEW

The Earth’s climate has always changed; the paleo-record of the last million years 

shows large changes with the growth and retreat of the great ice sheets over the 

continents. Nevertheless, over the past century the northern hemisphere has warmed 

at a rate faster than at any other time over the last millennium, and that change is 

because human activities are altering the chemical composition of the atmosphere 

through the buildup of GHGs, primarily CO2, CH4, N2O, and HFCs. These gases play a 

role in the “greenhouse effect”, a natural phenomenon that helps regulate the 

temperature of the Earth. Human activities, primarily the burning of fossil fuels and 

clearing of forests, have greatly intensified the natural greenhouse effect, causing global 

warming. Emissions of GHGs due to human activities have increased globally since 

pre-industrial times, with an increase of 70 percent between 1970 and 200415.

Though CO2 is the single most important anthropogenic GHG, non-CO2 anthropogenic 

GHGs, such as CH4, N2O, and HFCs, play a significant role in the Earth’s energy 

balance. Hence, control of non-CO2 GHGs is a critical component of climate change 

mitigation efforts, and particularly in the near term these reductions can complement 

early efforts to control CO2. Climate change can also be affected by the increase of 

ozone levels in the troposphere. Ozone is produced by photochemical reactions. Its 

precursor components are primarily the result of fossil fuel combustion. Unlike many of 

the other GHGs, ozone is a short-lived gas that is found in regionally varying 

concentrations. Nevertheless, it is a strong GHG and its global mean concentration has 

increased by about 35% since the pre-industrial times, with some regions experiencing 

larger and some with smaller increases. 

 15 IPCC. (2007a). Climate Change 2007: Synthesis Report. Contribution of Working Groups I, II and III to the Fourth 

Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press. 

http://www.ipcc.ch/pdf/assessment-report/ar4/syr/ar4_syr.pdf .
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The large interest in airborne particles and their radiative impact is derived in part from 

the Intergovernmental Panel on Climate Change (IPCC)’s assertion that human-caused 

climate change has resulted primarily from changes in the amounts of GHGs in the 

atmosphere, but also from changes in small particles. Major components of fine 

particles such as sulfate, nitrate, organic carbon, dust, and sea salts have reflective 

properties that scatter radiation (negative radiative forcing or cooling impact). Of the 

20+ models used in the IPCC 4th assessment report, most included sulfate direct 

radiative forcing, but only a fraction considered other aerosol types. The primary 

purpose was to establish whether the pattern of warming was altered by including 

aerosol-induced cooling in regions of high emissions. Carbonaceous particles (those 

that contain organic and black carbon) are particularly important because of their 

abundance in the atmosphere, and the characteristics of the carbon vary significantly 

depending on their origin. In recent years there has been increased attention in the 

particle research community about the potential of black carbon (BC) to cause global 

warming. The ability of BC to absorb light energy and its role in key atmospheric

processes link it to a range of climate impacts, including increased temperatures, 

accelerated ice and snow melt, and disruptions to precipitation patterns.

The heat-trapping property of GHGs is undisputed. Although there is uncertainty about 

exactly how and when the earth’s climate will respond to increasing concentrations of 

GHGs, combining observations with climate models indicates that detectable changes 

are under way. These observed changes go beyond a global mean rise in temperature, 

including also changes in regional temperature extremes, precipitation, and sea level, 

all of which could have significant adverse effects on water resources, ecological 

systems, and human health and the economy.

Global warming is already impacting the Western U.S., particularly California in more 

severe ways than the rest of the country. The 2010 Climate Action Team (CAT) report16

concluded that climate change will affect virtually every sector of the state’s economy 

and most of our ecosystems. Significant impacts will likely occur even under moderate 

scenarios of increasing global GHG emissions and associated climate change.

Compared to the rest of the country, California is particularly vulnerable to significant 

resource and economic impacts from at least three effects of climate change. First, as 

sea level rise and coastal erosion and flooding increase, California (with its long 

coastline) will experience loss of, and damage to, coastal property, infrastructure, 

recreational beaches, wildlife habitat, and coastal water supplies. Second, California 

relies on its snowpack for water supply and storage, and this resource is predicted to 

decrease substantially this century. Third, California’s urban, suburban, and rural areas 

are highly impacted by wildfires in ways most of the country simply does not face, and 

climate change will increase the incidence and severity of wildfires and resulting air 

quality and economic impacts. In addition, California is a major contributor to the 

 16 Climate Action Team (CAT 2010) Report to the Governor and Legislature; available at 

http://www.energy.ca.gov/2010publications/CAT-1000-2010-004/CAT-1000-2010-004.PDF
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nation’s food supply; increasing droughts and higher temperatures put this production at 

risk. 

After considering both observed and projected future effects of climate change 

(including key uncertainties, and the full range of risks and impacts to public health and 

welfare occurring within the State), the evidence points to the conclusion that climate 

change is already occurring at levels that harm our health and welfare, and that the 

effects will only worsen over time in the absence of regulatory action. California's 

transportation sector is the single largest contributor of GHGs in the State, producing 

close to 40% of all such emissions. On State highways in the coming decades, vehicle 

miles traveled are expected to continue to outstrip population growth under “business as 

usual” scenarios. Longer commute distances also have contributed to increases in 

vehicle miles traveled, while congestion has continued to increase; both factors 

contribute to GHG emissions. These trends indicate that if action is not taken that 

achieves significant long-term emission reductions, climate change will continue and its 

effects will worsen.

This chapter first presents the causes and projections for climate change (Section

III.A.1.1). The chapter then discusses climate change pollutants (Section III.A.1.2), 

definition of global warming potentials used in the proposed regulation (Section 

III.A.1.3), indicators of climate change in California (Section III.A.1.4), and potential 

impacts of climate change on California (Section III.A.1.5). The chapter concludes with 

a brief discussion of abrupt climate change (Section III.A.1.6).

1.1. Climate Change Causes and Projections

Climate change is a shift in the "average weather" that a given region experiences. This 

is measured by changes in the features that we associate with weather, such as 

temperature, wind patterns, precipitation, and storms. Global climate change means 

change in the climate of the Earth as a whole. Global climate change can occur 

naturally; an ice age (due to variations in the Earth's orbit and inclination toward the sun 

that cause cyclical variations in solar energy received by the Earth) is an example of

naturally occurring climate change. The Earth's natural climate has always been, and 

still is, constantly changing. The climate change we are seeing today, however, differs 

from previous climate change in both its rate and its magnitude. 

The temperature on Earth is regulated by a system commonly known as the 

"greenhouse effect". Naturally occurring GHGs, primarily water vapor, CO2, CH4, and 

N2O, absorb heat radiated from the Earth's surface. As the atmosphere warms, it in 

turn radiates heat back to the surface, to create what is commonly called the 

"greenhouse effect". The Earth's surface temperature would be about 34°C (61°F) 

colder than it is now if it were not for the natural heat trapping effect of GHGs. Water 

vapor is the most abundant and important of these naturally occurring GHGs. In 

addition to its direct effect as a GHG, clouds formed from atmospheric water vapor also 

affect the heat balance of the Earth by reflecting sunlight (a cooling effect), and trapping 

infrared radiation (a heating effect). Human activities add and subtract water vapor to 
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and from the atmosphere; however, these amounts are insignificant compared to the 

water moved by natural processes. 

Fluctuations in levels of natural GHGs have been measured over the past 650,000 

years. However, there are several reasons for attributing the rise in GHGs over the past 

250 years to human activity rather than to naturally occurring climatic changes. The 

IPCC 4th assessment report (2007b)17 confirms that over the past 8,000 years, prior to 

industrialization in 1750 , CO2 concentration in the atmosphere increased by a mere 20 

parts per million (ppm). The concentration of atmospheric CO2 in 1750 was 280 ppm, 

and increased to 379 ppm in 2005. That is an enormous increase of 100 ppm in 250 

years. For comparison, at the end of the most recent ice age there was approximately 

an 80 ppm rise in CO2 concentration. This rise took over 5,000 years. Higher values 

than what we see today have only occurred many millions of years ago.

Human activities are exerting a major and growing influence on some of the key factors 

that govern climate by changing the composition of the atmosphere and by modifying 

the land surface. The human impact on these factors is clear. This increase has 

resulted from the burning of coal, oil, and natural gas, and the destruction of forests 

around the world to provide space for agriculture and other human activities. Rising 

concentrations of CO2 and other GHGs are intensifying the Earth’s natural greenhouse 

effect. 

In its most recent assessment on climate change, the IPCC provided an estimate of 

global GHG emissions and projections of surface temperatures from 2000 to 2100 

under six likely scenarios. Each scenario reflects a particular path for human society to 

grow. The main hypotheses concerning demography, agricultural practices, technology 

spreading, etc. are turned - through simple models - into projections about energy 

consumption, food production, and the corresponding GHG emissions. The IPCC 

report18 projects an increase of global GHG emissions by 25% to 90% (CO2e) between 

2000 and 2030 (see Figure III-A-1-1 below taken from IPCC 2007 synthesis report), with 

fossil fuels maintaining their dominant position in the global energy mix to 2030 and 

beyond. Including uncertainties in future GHG concentrations and climate modeling, the 

IPCC anticipates a warming of 1.1 C to 6.4 C (2.0°F to 11.5°F) by the end of the 

21st century. 

 17 IPCC. (2007b). Technical Summary: Climate Change 2007: The Physical Science Basis, Contribution of Working 

Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University 

Press. https://www.ipcc-wg1.unibe.ch/publications/wg1-ar4/ar4-wg1-ts.pdf 18 IPCC (2000), Special Report on Emissions Scenarios (SRES), available at http://www.ipcc.ch/pdf/specialreports/spm/sres-en.pdf
Page 77

Figure III-A-1-1. Global GHG emission and temperature projections under different GHG 

emissions scenarios (taken from IPCC 2007c 19)

All emissions scenarios result in an increase in the atmospheric concentration of 

CO2. For the six illustrative scenarios, the projected concentrations of CO2 in the year 

2100 range from 560 to 970 ppm, compared to about 280 ppm in the pre-industrial era 

and about 388 ppm in the year 2010. Every scenario imagines a world in which no 

explicit action is taken to combat GHG emissions. In the lowest-emission scenario, B1, 

it is assumed that technical and societal developments lead to a reduction in the use of 

fossil fuels. In this case, CO2 levels are expected to continue rising, but to stabilize at a 

level that is roughly twice the pre-industrial level. Most analysts suggest that a doubling 

of GHG concentrations from pre-industrial levels will increase global temperatures about 

3°C from pre-industrial levels, although many studies suggest the climate could be even 

more sensitive to a doubling of CO2 concentrations. 

Substantial scientific evidence indicates that an increase in the global average 

temperature of 2°C above pre-industrial levels (about 1.1o

C above present levels) poses 

severe risks to natural systems and human health and well-being. Stabilizing the CO2

concentrations at or below 450 ppm offers a 50% chance of keeping the global average 

temperature from rising more than 2°C, or 3.6°F, above pre-industrial levels. The same 

level is believed to result in a 33% chance of temperatures rising more than 3°C. 

Therefore, a 450 ppm CO2 stabilization target generally represents the upper limit for 

the concentration of heat-trapping emissions in global policies that seek to avoid 

catastrophic climate change. Recent empirical evidence indicates climate change is 

taking place considerably faster than scientists had expected only a decade ago. 

Furthermore, paleoclimatic research indicates that earlier climate change episodes also 

took place rapidly. If rapid change is occurring, a considerably lower policy target than 

450 ppm is justified. The goal of 350 ppm atmospheric CO2 is supported by the most 

up-to-date science.

 19 IPCC (2007c), Synthesis report; available at http://www.ipcc.ch/pdf/assessment-report/ar4/syr/ar4_syr_spm.pdf ).
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The concentration of GHGs in the atmosphere is determined by the difference between 

the rate of emissions and the rate of uptake by the world’s ecosystems and oceans.

Since the rate of CO2 emissions currently exceeds the rate of uptake, halting emissions 

is not enough to stop the build-up of atmospheric CO2. Temperatures will continue to 

rise long after emissions are reduced and GHG concentrations are stabilized. Hence, 

reducing GHG concentrations in the atmosphere to the lowest feasible level is critical to 

limiting warming to no more than 2oC. There is considerable uncertainty as to whether 

we will reach the 2oC target given the lack of prompt and meaningful global action. 

Executive Order S-3-05 established GHG targets for the State such as: returning to year 

2000 emission levels by 2010; 1990 levels by 2020; and 80 percent below 1990 levels 

by 2050. If the industrialized world were to follow California’s lead, it would increase the 

likelihood that California and the world would be on track to avoid the more severe 

climate change impacts. This estimate of the impact of an 80 percent reduction by the 

industrialized world has on global emissions depends crucially on the growth rate and 

energy strategies of the developing world.

In the Kyoto Protocol a number of industrialized countries (the “Annex I Parties”) made 

commitments to limit or reduce GHG emissions by 2012. The current internationallyagreed mitigation targets apply only to industrialized countries and do not extend 

beyond 2012. Successfully limiting emissions in order to stabilize atmospheric GHG 

concentrations at acceptable levels will require the participation of all major emitting 

countries. The “most challenging” mitigation case would stabilize atmospheric 

concentrations of CO2 at 450 ppm. This is significant because avoiding substantial 

temperature change by mid-century is a starting point for achieving more aggressive 

long-term targets. The 450 ppm target would make it possible to limit long-term global 

mean temperature increases and to avoid some of the most severe risks of climate 

change. 

The climate system is highly dynamic: External “forcings” such as anthropogenic GHG 

emissions, “reflective” aerosol particles from volcanoes and fossil fuel combustion, and 

solar radiation alter the amount of radiation in the Earth’s atmosphere. “Feedbacks” 

(such as cloud or ice-albedo feedbacks) amplify or dampen the effect of forcings. While 

all climate models project that significant warming will result of rising GHG 

concentrations, the amount of warming that will result from anthropogenic GHG 

emissions will depend on the intensity of and interactions between these forcings and 

feedbacks. The consequences of the warming will depend on the degree and speed of 

temperature rise, and the internal dynamics of the climate system—the atmosphere, 

oceans, land, ice sheets, and biosphere—and whether or not any non-linear climate 

thresholds are reached that result in catastrophic damages (IPCC 2007, Synthesis 

Report).

1.2. Climate Change Pollutants

Naturally occurring GHGs include water vapor, carbon dioxide, methane, nitrous oxide, 

and ozone (O3). Several classes of halogenated substances that contain fluorine, 
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chlorine, or bromine are also GHGs, but they are, for the most part, solely a product of 

industrial activities. Chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons 

(HCFCs) are halocarbons that contain chlorine, while halocarbons that contain bromine 

are referred to as bromofluorocarbons (i.e., halons). 

Because CFCs, HCFCs, and halons are substances which deplete stratospheric ozone, 

they are regulated by the Montreal Protocol on Substances that Deplete the Ozone 

Layer. The United Nations Framework Convention on Climate Change (UNFCCC) 

defers to this earlier international treaty; consequently these gases are not included in 

national GHG inventories. However, large quantities of CFCs, halons, and other ozone 

depleting substances (ODS) produced prior to phase-out deadlines under the Montreal 

Protocol remain legally in use or storage in older equipment, building and appliance 

insulation, and other “banks.” ODSs not only contribute to the depletion of the 

stratospheric ozone layer, but they are also potent GHGs with global warming potentials 

up to thousands of times higher than CO2. Without intervention, most of the banks are 

expected to be emitted by 2020 as a result of regular equipment and appliance 

turnover. The window for addressing emissions from banks is relatively narrow with 

every year lost translating into millions of tons of CO2e emitted. 

The Parties to the Montreal Protocol are preparing to take another important step 

towards better ozone layer protection and climate change mitigation to promote the 

destruction of ODS banks. These proposals seek to recover and destroy ODSs before 

they are emitted from existing stockpiles and from discarded products and equipment, 

and before they harm the ozone layer and climate system. To reduce statewide GHG 

emissions to 1990 levels by 2020, CARB is also considering policies to reduce emissions 

of high global warming potential gases—including ODS as well as ODS substitutes.

Other fluorine-containing gases—hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), 

and sulfur hexafluoride (SF6)—do not deplete stratospheric ozone but are potent GHGs.

These latter substances are addressed by the UNFCCC and accounted for in State and 

national GHG inventories. GHG concentrations in the atmosphere are a function of 

both the emissions of the GHGs and the effective lifetime of these gases. Because it 

takes one to two years to mix the emissions of a species throughout the troposphere, 

gases that are chemically stable and persist in the atmosphere over time scales of 

decades to centuries or longer are referred to in the IPCC as “long-lived” or “well-mixed” 

gases.

Each gas has a characteristic lifetime that is a function of the total atmospheric burden 

and the removal mechanism (i.e., sinks) for that gas. Each GHG has different 

interactions of each gas with the various available sinks, which include chemical 

reaction with the hydroxyl (OH) free radical or other highly reactive species, photolysis 

by sunlight, dissolution into the oceans, reactions on the surface, biological processes, 

or other mechanisms. According to the IPCC (2007), the lifetime of the HFCs of 

industrial importance range from 1.4 to 270 years, the lifetime of N2O is 114 years, the 

lifetime of CH4 is 12 years, and the lifetime of the PFCs and SF6 range from 1,000 to 

50,000 years. Carbon dioxide has a very different life cycle compared to the other 
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GHGs, which have well-defined lifetimes. Instead, unlike the other gases, CO2 is not 

destroyed by chemical, photolytic, or other reaction mechanisms, but rather the carbon 

uptake in CO2 cycles between different reservoirs in the atmosphere, ocean, land 

vegetation, soils, and sediments. 

Historic data show that current atmospheric concentrations of the two most important 

directly emitted, long-lived GHGs (CO2 and CH4) are well above the natural range of 

atmospheric concentrations compared to at least the last 650,000 years. Atmospheric 

GHG concentrations have been increasing because anthropogenic emissions have 

been outpacing the rate at which GHGs are removed from the atmosphere by natural 

processes over timescales of decades to centuries.

The California GHG inventory compiles statewide anthropogenic GHG emissions and 

sinks. It includes estimates for CO2, CH4, N2O, SF6, nitrogen trifluoride (NF3), HFCs, 

and PFCs. The current inventory covers years 2000 to 2008 (available 

at http://www.arb.ca.gov/cc/inventory/data/data.htm). Individual climate change

pollutants are briefly discussed in the following sections.

Carbon Dioxide (CO2): California's total CO2 emissions from fossil fuel combustion in 

2008 were 485 million metric tons of CO2 equivalent (MMTCO2e), and represent about 

89% of California’s total GHG emissions. Annual statewide emission inventories 

provide the basis for establishing historical emission trends. There are many factors 

affecting GHG emissions and year to year changes, including the state of the economy, 

changes in demography, improved efficiency, and changes in environmental conditions 

such as drought. In 2008, California observed a small decrease in statewide GHG 

emissions, driven by a noticeable drop in on-road transportation emissions. 2008 also 

reflects the beginning of the economic recession and fuel price spikes. 

Despite lower overall GHG emissions in 2008, transportation remained the largest 

source with 36% of California’s gross inventory. On-road emissions (from passenger 

vehicles and heavy-duty trucks) constitute 93% of the transportation sector total. Onroad emissions grew to a maximum of 171 MMTCO2e in 2005, plateaued until 2007, 

and decreased in 2008 to 163 million. The amount of gasoline and diesel fuel 

consumed by on-road vehicles followed a similar trend. As the economy recovers, 

GHG emissions are likely to rise again without other mitigating actions.
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Figure III-A-1-2. California’s 2008 GHG emissions by Sector

Source: http://www.arb.ca.gov/cc/inventory/data/graph/graph.htm

Methane (CH4): Methane accounted for approximately 5% (29 MMTCO2e) of gross 

2008 GHG emissions in California. Methane is produced during anaerobic 

decomposition of organic matter in biological systems. Decomposition occurring in 

landfills accounts for the majority of anthropogenic CH4 emissions in California and in 

the United States as a whole. Agricultural processes such as enteric fermentation, 

manure management, and rice cultivation are also significant sources of CH4 in 

California. Methane emission levels from a source can vary significantly from one 

region to another, depending on many factors such as climate, industrial and 

agricultural production characteristics, energy types and usage, and waste management 

practices. Results of a study20 indicate that current inventory of CH4 emissions from the 

Central Valley are underestimated; suggesting that actual CH4 emissions could be 

about 20-60% higher than California-specific inventory estimates.

Nitrous Oxide (N2O): Another gas that contributes to global warming is N2O. 

Agricultural soil management activities and mobile source fuel combustion compose the 

major sources of these emissions. N2O emissions comprised around 3% (14 MMT 

CO2e) of California’s overall GHG emissions in 2008. Nitrous oxide emission levels 

from a source can also vary significantly from one region to another, depending on 

many factors such as industrial and agricultural production characteristics, combustion 

technologies, waste management practices, and climate. For example, utilization of 

synthetic nitrogen fertilizers in crop production typically results in more N2O emissions 

from agricultural soils than that occurring from less intensive, low-tillage techniques. 

Also, the presence or absence of control devices on combustion sources, such as 

 20 Zhao, C., A. E. Andrews, L. Bianco, J. Eluszkiewicz, A. Hirsch, C. MacDonald, T. Nehrkorn, and M. L. Fischer 

(2009), Atmospheric inverse estimates of methane emissions from Central California, J. Geophys. Res., 114, 

D16302, doi:10.1029/2008JD011671.
Page 82

catalytic converters on automobiles, can have a significant effect on the level of N2O 

emissions from these types of sources. The IPCC provides default emission factors. 

Using the IPCC default values as opposed to conducting monitoring programs could 

introduce a large degree of uncertainty. Hence; it seems the current estimates of N2O 

emissions may be underestimated.

In addition to CO2 emissions, light-duty vehicle GHG emissions also include CH4 and 

N2O. Although emissions of these compounds are generally orders of magnitude lower 

than emissions of CO2, the global warming potential of both CH4 and N2O is greater 

than that of CO2. As a result, it is important to consider these emissions in determining 

the overall GHG impact potential of light-duty vehicles. It is important to recognize, 

however, that current vehicles produce and emit substantially less CH4 and N2O than 

their older counterparts and it is almost certain that future vehicles will exhibit even 

lower emission rates. Existing standards for non-methane organic compounds and NOX

result in reduced CH4 and N2O emissions through the design and implementation of 

advanced combustion and catalyst technologies.

Hydrofluorocarbons (HFCs), Perfluorocarbons (PFCs), and Sulfur Hexafluoride 

(SF6): HFCs, PFCs and SF6 accounted for another 3% of 2008 GHG emissions in 

California. HFCs are primarily used as substitutes for ozone-depleting substances 

regulated under the Montreal Protocol. PFCs and SF6 are generally emitted from 

various industrial processes including aluminum smelting, semiconductor 

manufacturing, electric power transmission and distribution, and magnesium casting. 

For vehicular HFC emissions (particularly HFC-134a), four emission sources, all related 

to air conditioning, should be considered: emissions leaking from the hoses, seals, and 

system components of vehicle air conditioning system, and emissions that are released 

when the air conditioning system is opened for servicing. HFC emissions can also 

occur when the vehicle is scrapped at the end of its useful life or due to sudden 

releases (e.g., traffic accident refrigerant releases). HFC-134a, commercially known as 

R-134a, is presently the vehicle refrigerant of choice among vehicle manufacturers.

Water Vapor (H2O): It should be noted that there’s an important difference between 

water vapor and other GHGs. Human activities do not seem to be appreciably changing 

the atmospheric concentration of water vapor in any direct way on the global average. 

Nor does water vapor accumulate in the atmosphere over the multi-year periods that 

other GHGs do. Natural processes (e.g., rain) remove water vapor when it reaches 

certain limits. Water stays in the atmosphere for a few days, while other GHGs linger 

for decades or centuries. The overall impact of water vapor with respect to global 

climate change is not well understood as it can lead to both warming (absorption of 

long-wave radiation from Earth) and cooling (cloud formation/reflection of solar 

radiation).

Other Radiatively Important Species: There are also several gases that do not have a 

direct global warming effect but indirectly affect terrestrial and/or solar radiation 

absorption by influencing the formation or destruction of GHGs, including tropospheric 
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and stratospheric ozone. These gases include carbon monoxide (CO), oxides of 

nitrogen (NOX), and non-CH4 volatile organic compounds (NMVOCs). The sequence of 

reactions that removes CO, NOX, and NMVOCs from the atmosphere, however, tends 

to promote the formation of tropospheric ozone (a potent GHG). The reactions that 

produce ozone or alter the losses of CH4 are strongly affected by the relative 

concentrations of various pollutants, the ambient temperature, and local weather 

conditions. At present, there is large scientific uncertainty in estimating their radiative 

forcing effects. The above listed compounds, regulated in the USEPA and California 

pursuant to the Clean Air Act, are often referred to as “criteria pollutants”. The criteria 

pollutants are reactive compounds, and they tend to remain in the atmosphere for a 

much shorter time than most other GHGs.

Aerosols, which are extremely small particles or liquid droplets, such as those produced 

by sulfur dioxide (SO2) or black carbon (BC) emissions, can also affect the absorptive 

characteristics of the atmosphere. Four of the more important aerosols are sulfates, 

nitrates, organic carbon, and BC. While some aerosols are directly emitted, others are 

formed through secondary reactions (for example, sulfates and nitrates can be formed 

by oxidation of SO2 and NOX respectively), and their properties can change as they mix 

and react in the atmosphere. Aerosols affect radiative forcing in both direct and indirect 

ways: directly by scattering and absorbing solar and thermal infrared radiation; and 

indirectly by altering the cloud properties and atmospheric heating rates that in turn 

modify the formation, precipitation efficiency, and radiative properties of clouds. The 

effect of aerosols on regional and global climate is complex: in general, sulfate aerosols 

enhance the reflection of sunlight and cool the Earth, while black carbon aerosols 

enhance the absorption of sunlight and warm the Earth. Appendix U provides a more 

detailed discussion of climate change impacts of black carbon particles.

Black carbon is the light-absorbing carbonaceous fraction of particulate matter (PM) that 

results from incomplete combustion of fossil fuels and biomass. In recent years, there 

has been increased attention in the particle research community to the potential of BC 

to cause global warming. The ability of BC to absorb light energy and its role in key 

atmospheric processes link it to a range of climate impacts, including increased 

temperatures, accelerated ice and snow melt, and disruptions to precipitation patterns. 

It has been proposed that light absorbing particles in the atmosphere act as a 

greenhouse pollutant whose net forcing is warming only second to CO2. Ramanathan 

and Carmichael21 estimate a BC forcing of 0.9 W/m2 or more than half of the 1.6 W/m2

attributed to CO2. This estimate of the forcing due to BC is larger than most prior 

estimates including those of the IPCC 4th assessment report. 

The relatively short atmospheric residence time (only a few weeks) of BC makes 

reductions in BC emissions a potential near-term opportunity to postpone the effects of 

rising GHG levels on the global climate. Unlike the benefits associated with reductions 

in GHG emissions which take decades to be fully realized, reductions in BC emissions 

yield immediate improvements. However, a number of issues that may impede policy 

 21 Ramanathan, V. and Carmichael, G. (2008) Global and regional climate changes due to black carbon. Nature 

Geoscience 156, 221-227.
Page 84

action include the fact that BC emissions are not covered in the Kyoto Protocol and the 

co-emission of BC with cooling pollutants, namely organic carbon, complicates 

accounting and development of effective interventions. Additional remaining 

uncertainties in BC climate effects (due to its ability to affect clouds) and the lack of an 

internationally agreed-upon global warming potential or other metric for BC are current 

obstacles towards a uniform policy framework and are likely to be research questions 

that should be addressed.

California’s unique emissions and fuel standards for cars, trucks, buses, motorcycles, 

and other motor vehicles have dramatically reduced criteria pollutant emissions, as 

have controls on non-automotive pollution sources that are administered by the State’s 

35 local air pollution control districts. California has achieved these improvements 

despite the State’s substantial growth in population, vehicle use, and business activities.

1.3. Global Warming Potentials

Radiative forcing is often defined as a net imbalance in energy flux in the atmosphere, 

and is expressed in watts per square meter (W/m2

), (i.e., heat per area of the Earth's 

surface). Radiative forcing of the surface-troposphere system, resulting, for example, 

from a change in GHG concentrations, is the change in the balance between radiation 

coming into the atmosphere and radiation going out. A positive radiative forcing tends, 

on average, to warm the surface of the Earth, and negative forcing tends, on average, 

to cool the surface. The impact of a GHG emission upon the atmosphere is related not 

only to radiative properties of the gas and its initial abundance, but also to the length of 

time the GHG remains in the atmosphere. Radiative properties control the absorption of 

radiation per kilogram of gas present at any instant, but the lifetime of the gas controls 

how long an emitted kilogram remains in the atmosphere and hence its cumulative 

impact on the atmosphere's thermal budget. The climate system responds to changes 

in the thermal budget on time-scales ranging from the order of months to millennia 

depending upon processes within the atmosphere, ocean, and biosphere.

Gases in the atmosphere can contribute to the greenhouse effect both directly and 

indirectly. Direct effects occur when the gas itself is a GHG. Indirect radiative forcing 

occurs when chemical transformations of the original gas produce other GHGs, when a 

gas influences the atmospheric lifetimes of other gases, and/or when a gas affects 

atmospheric processes that alter the radiative balance of the Earth (e.g., cloud 

formation). The concept of a Global Warming Potential (GWP) has been developed in 

parallel to the concept of ozone depletion potential developed under the Montreal 

Protocol to compare the ability of each GHG to trap heat in the atmosphere relative to 

another gas. CO2, the primary anthropogenic GHG, has been chosen as the reference 

gas. 

GWP is defined as the ratio of the time-integrated radiative forcing from the release of 

1 kilogram of a trace substance relative to that of 1 kg of CO2 (IPCC 2007). While any 

length of integration can be selected, the 100-year GWPs are recommended by the 

IPCC and are employed by ARB for policy-making and reporting purposes. 
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GWP values allow a comparison of the impacts of emission changes (reductions or 

increases) of different gases. In addition to communicating GHG emissions in units of 

mass, we have also chosen to use GWPs to reflect their inventories in CO2 equivalent 

terms because it effectively places all of the GHGs on the same comparative scale. It 

should be noted that when the lifetime of the species in question differs substantially 

from the response time of CO2 (nominally about 150 years), then the GWP becomes 

very sensitive to the choice of time horizon. The GWP concept is only relevant for 

compounds that have sufficiently long lifetimes to become globally well-mixed. 

Therefore, short-lived gases and aerosols with varying atmospheric distributions and 

lifetimes pose a problem in the simple GWP framework.

Table III-A-1-1 lists GWPs for CO2, CH4, N2O, HFCs, PFCs, and SF6 for the 20-, 100-, 

and 500-year time horizons. Assembly Bill 1493 calls for reductions in GHGs, which are 

defined in the bill as CO2, CH4, N2O, HFCs, PFCs, and SF6. The first four of these 

identified GHGs are clearly associated with motor vehicle use in California. PFCs and 

SF6 are not known to be associated with motor vehicle emissions in California and 

therefore are not addressed further in the staff report. Table III-A-1-1 includes all six 

climate change pollutants including CO2, CH4, and N2O, hydrofluorocarbons (HFCs), 

perfluorocarbons (PFCs), and sulfur hexafluoride (SF6) that are proposed/listed in 

AB32.

As mentioned earlier, in addition to the six GHGs identified above, there are a number 

of man-made pollutants, emitted primarily as byproducts of combustion (both of fossil 

fuels and of biomass), that affect the climate. Several of these substances have both 

warming and cooling effects, with considerable uncertainty as to the net effect. Those 

generally believed to result in net warming include CO, NMVOC, and the fraction of 

particulate matter (PM) substantially consisting of BC. The 2007 IPCC states that in 

addition to the gases targeted in the Kyoto Protocol, the contribution of tropospheric O3

to the greenhouse effect is also important. The report further states that in order to curb 

global warming it is necessary to reduce the emissions of both GHGs and other gases 

that influence the concentration of GHGs. Air pollutants such as NOX, CO, and 

NMVOC generate O3 and impact tropospheric OH radicals, which in turn alters CH4

levels. Hence, they are called indirect GHGs. This interrelationship of direct and indirect 

GHGs is one reason it is important to simultaneously control smog-forming and 

particulate matter pollutants, as well as the “traditional” six GHGs such as CO2, 

sometimes with the same technologies (e.g. advanced hybrid technology and zeroemission vehicles). 
Page 86

Table III-A-1-1. Numerical Estimates of Global Warming Potentials Compared With CO2

(Kilograms Of Gas Per Kilogram Of CO2 -- Adapted From IPCC 2007d22)

Climate 

Pollutants

Lifetime 

(years)

Global Warming Potential

20 years 100 years 500 years

CO2 ~150 1 1 1

CH4 12 72 25 7.6

N2O 114 289 298 153

HFCs (depending 

on type of HFC)

2-270 437-12,000 124-14,800 38-12,200

PFCs (depending 

on type of PFC)

740-50,000 5,210-13,200 7,390-17,700 11,200-21,200

SF6 3,200 16,300 22,800 32,600

All of these substances have significantly greater uncertainty associated with 

quantifying their impacts on climate than the six pollutants identified in the Kyoto 

Protocol. This is partly due to the fact that their impacts occur by influencing the 

concentrations of direct GHGs through a series of complex chemical reactions, and their 

high chemical activity and large variation in source strengths lead to temporal and 

spatial variations. Therefore, these other agents typically have not been directly 

included in climate-related emission reduction efforts due to scientific uncertainty 

regarding the magnitude or direction of their climate change effect and difficulty in 

quantifying their impact in terms of “CO2 equivalent”, which is the standard metric of 

global warming potential. 

In summary, multi-component abatement strategies to limit human-induced climate 

change need a framework and numerical values for the trade-off between emissions of 

different GHGs. Alternative metrics to compare emissions of GHGs can result in very 

different priorities for abatement of different gases in mitigation strategies. The GWP 

with a 100 year time horizon is the most widely accepted metric for comparing GHGs. 

Although shortcomings have been identified, no other metric has gained comparable 

status to GWPs. Both at the national and international levels, the GWP remains an 

appropriate metric for comparing the potential climate impact of the emissions of 

different forcing agents.

1.4. Indicators of Climate Forcing and Climate Change in California

Over the last several decades, evidence of human influences on climate change has 

become increasingly clear and compelling. There is indisputable evidence that human 

activities are adding to the concentrations of greenhouse gases that are already 

naturally present in the atmosphere. These heat-trapping gases are now at record-high 

 22 IPCC (2007d), Working Group I: The Physical Science Basis, Chapter 2: Changes in Atmospheric Constituents and 

in Radiative Forcing, available at http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-chapter2.pdf
Page 87

levels in the atmosphere compared with the recent and distant past. Warming of the 

climate system is well documented, evident from increases in global average air and 

ocean temperatures, widespread melting of snow and ice, and rising global average sea 

level. Most of the observed increase in global average temperatures since the mid20th century is very likely due to the observed increase in anthropogenic GHG 

concentrations (IPCC 2007a). 

Indicators of climate forcing and actual climate change can be used to illustrate trends, 

measure the suitability of particular actions in certain areas, measure progress made in 

meeting climate change policy targets, identify requirements for adaptation and 

mitigation measures, and encourage public awareness of the climate change impacts. 

Hence, collecting and interpreting environmental indicators has played a critical role in 

our increased understanding of climate change and its causes. An indicator represents 

the state of certain environmental conditions over a given area and a specified period of 

time. Examples of climate change indicators include temperature, precipitation, sea 

level, and GHG concentrations in the atmosphere. 

Trends in GHG emissions are useful in these areas. Atmospheric CO2 and other GHG 

concentrations are a key indicator for international negotiations on emission reduction. 

Climate and atmospheric variables such as temperature change and trends in 

precipitation are also important. In general, indicators to describe the impact of climate 

change on human health are still limited due to lack of data. Climate change can 

exacerbate heat waves resulting in higher rates of morbidity and mortality. 

Furthermore, higher temperatures could lead to an increase of water and food related 

diseases. Scientists, analysts, decision-makers, and others use environmental 

indicators, including those related to climate, to help track trends over time in the state 

of the environment, key factors that influence the environment, and effects on 

ecosystems and society.

California began one of the earliest efforts to track and reduce greenhouse gas 

emissions and to support research to better understand climate change and its impacts. 

Palpable signs or “indicators” of climate change in California can be found in this wealth 

of scientific research and environmental monitoring. These indicators help tell the story 

of how California’s climate is changing and how these changes are influencing many of 

our natural systems. Several potential climate change indicators have been suggested, 

including anthropogenic GHG emissions, air temperature, annual Sierra Nevada snow 

melt runoff, and sea level rise in California (EPIC, 2009)23. Changes occurring in 

California are largely consistent with those occurring globally. In summary, the 

indicators of climate change in the 2009 EPIC report show the following:

• Emissions of GHGs have increased since 1990, with CO2 from the combustion of 

fossil fuels for transportation accounting for the largest proportion of emissions. 

The contribution of GHG from the combustion of different fuels varies by fuel 

 23 Office of Environmental Health Hazard Assessment. Environmental Protection Indicators for California (EPIC), 

2009. Available at: http://oehha.ca.gov/multimedia/epic/pdf/ClimateChangeIndicatorsApril2009.pdf ). 
Page 88

type. Nonrenewable fossil fuels are used more than any other fuel type in 

California and emissions from the combustion of gasoline and natural gas have 

increased the most between 1990 and 2004. 

• Atmospheric concentrations of CO2 have been increasing in coastal areas of the 

state, consistent with global trends. Measurements at La Jolla, as well as shorter 

term measurements at Trinidad Head and Point Arena, are consistent with global 

trends, as represented by the measurements at Mauna Loa, Hawaii. 

• Temperature data have been collected at many weather stations in the State for 

almost a century. The air temperature indicator can be used to track trends in 

statewide surface air temperatures and regional variations, allowing for a 

comparison of temperature changes in California with those occurring globally. 

Air temperatures have increased over the past century, with nighttime minimum 

temperatures showing a greater rate of increase than daytime maximum 

temperatures. The 11 climate regions within the State are showing the same 

warming trends over the last century. The entire State has been warming in both 

minimum and mean temperatures, at approximately 2o

F per century. There are 

modest differences around the State in the rate of daytime warming. Counties 

with populations over 1 million are warmer than those with populations under 

100,000. Conversely, counties with less than 100,000 people had the lowest 

average rate of temperature increase. The rate of temperature increase -- 0.7o

F 

(0.5o

C) per century -- from the rural group agrees with a global estimated mean 

surface temperature increase of 0.5 to 1.0oF (0.3 to 0.6oC) since the 19th century.

• Summertime temperature extremes, especially at night, have been decreasing 

over the past half century. Likewise, winter chill hours, a factor critical for fruit 

trees to produce flowers and fruit, have been decreasing in the fruit growing 

valleys of California over the same time period.

• Precipitation in the form of rain and snow is a major component of the biological 

and economic lifeblood of California. The historical likelihood of wet and dry 

episodes of various durations must be factored into planning for management of 

water resources (municipal and industrial water supplies, agriculture, 

hydropower, recreation, fish habitat, and others) and in planning for both floods 

and droughts. Over the entire 112-year period of record, the linear trend of 

annual precipitation is an increase of about 17 percent per century. Of note are 

the large year-to-year variations in precipitation, particularly since the 1930s, and 

long episodes of consecutive dry or wet years at many times during the 

observational record.

• The warming of global climate could increase evaporation rates, thereby 

potentially increasing precipitation and storms in the State. Snowmelt and runoff 

volume data can be used as a climate change indicator to document changes in 

runoff patterns. For example, the percentage of annual runoff fraction during the 

spring snowmelt period of the Sacramento River has decreased by 10 percent 
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since 1906. Less spring runoff can reduce the amount of potential summer water 

available for the State’s water needs and hydroelectric power production. These 

specific regional changes are related, at least in part, to the climate change 

associated with the observed global mean warming. In California, large 

accumulations of snow occur in the Sierra Nevada and southern Cascade 

Mountains from October to March. Each winter, at the high elevations, snow 

accumulates into a deep pack, preserving much of California’s water supply in 

cold storage. If the winter temperatures are warm, more of the precipitation falls 

as rain instead of snow, and water directly flows from watersheds before the 

spring snowmelt. Thus, there is less buildup of snow pack; as a result, the 

volume of water from the spring runoff is diminished. Less spring runoff can 

reduce the amount of potential summer water available for the state’s water 

needs and hydroelectric power production. Lower runoff volumes can also 

impact recreation opportunities, and impair cold water habitat for salmonid fishes. 

• Snow-water contents have trended towards less water stored in snow-packs in 

the Northern Sierra Nevada, and towards more water stored in snow-packs in the 

Southern Sierra Nevada during the past several decades. During spring, snowwater contents have declined by about 15 percent in the northern Sierra Nevada 

since 1950, while increasing by about 15 percent in the southern Sierra Nevada.

Together, the decreases in the north and increases in the south have combined 

to yield little or no net change in the statewide snow-water content averages.

• Glaciers are important indicators of climate change. Over the 20th century, with 

few exceptions, alpine glaciers have been receding throughout the world in 

response to a warming climate. The surface area of seven Sierra Nevada 

glaciers has decreased over the past century. In 2004, the area of these seven 

glaciers ranged from 22 to 69 percent of their 1900 area.

• Sea level rise provides a physical measure of possible oceanic response to 

climate change. Increasing global mean temperatures will result in the rise in 

mean sea level. Warming of the ocean water will cause a greater volume of sea 

water because of thermal expansion. This contributes the largest share of sea 

level rise, followed by melting of mountain glaciers and ice caps.

• Along California’s coast, sea level already has risen by three to nine inches over 

the last century (three inches at Los Angeles, eight inches at San Francisco, and 

an estimated nine inches at La Jolla near San Diego), and it is likely to rise by 

another 7 to about 30 inches by 2100. Differences in sea level rise along the 

coast can occur because of local geological forces, such as land subsidence and 

plate tectonic activity. Global warming studies predict that global sea level will 

rise at an accelerated rate, much beyond that seen in prehistoric natural cycles of 

warming and cooling evidenced by geologic data.

• The scientific evidence suggests that terrestrial, marine and freshwater biological 

systems are also being strongly influenced by recent warming. From 1983 to 
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2004, tree mortality resulting from stress and biotic causes (as opposed to 

mechanical causes) in temperate old-growth forests of the Sierra Nevada has 

increased at the average rate of 3 percent per year. The increase in mortality 

rate coincides with a temperature-driven increase in estimated climatic water 

deficit, a measure of drought. 

• Large-wildfire (fire event ≥400 hectares) activity in western U.S. forests increased 

suddenly and markedly in the mid-1980s. From 1987 to 2003, wildfire frequency 

was nearly four times the average number, and the total area burned was more 

than six times the level seen between 1970 and 1986. Inter-annual variability in 

wildfire frequency is strongly associated with regional spring and summer 

temperature. Also, when comparing 1970-1986 with 1987-2003, the length of the 

yearly wildfire season (March through August) extended by 78 days, a 64 percent 

increase, and the duration of individual fires increased from one week to about 

five weeks.

• The lower edge of the conifer-dominated forests in the Sierra Nevada has been 

retreating upslope over the past 60 years. The spring and fall arrivals of some 

migratory birds are changing. Small mammals in Yosemite National Park are 

found today at different elevational ranges compared to earlier in the century. 

Butterflies in the Central Valley have been arriving earlier in the spring over the 

past four decades. 

The climate change indicators described above represent key properties of the climate 

system that are considered sensitive to climate change. Many additional potential 

indicators remain to be explored. For example, climate change may influence the 

frequency of extreme weather events, ecosystem structures and processes, and 

species distribution and survival. It may affect forestry, energy and other industries, 

insurance and other financial services, and human settlements. In addition, the impacts 

can vary from one region, ecosystem, species, industry, or community to the next. 

Research into the regional impacts of climate change is ongoing, and the potential 

climate change indicators will be updated and expanded as new information becomes 

available.

1.5. Potential Impacts on California

Climate is a central factor in Californian life. It is at least partially responsible for the 

State’s rapid population growth in the past 50 years, and largely responsible for the 

success of industries such as agriculture and tourism. The potential effects of climate 

change on California have been widely discussed from a variety of perspectives. The 

signs of a global warming trend continue to become more evident and much of the 

scientific debate is now focused on expected rates at which future changes will occur. 

Climate change poses serious risks to California’s natural resources. California-specific 

impacts are expected to include changes in temperature, precipitation patterns, and 

water availability, as well as rising sea levels and altered coastal conditions. These 
Page 91

physical changes will have economic repercussions across the California economy, 

including in agriculture, forestry, energy production and consumption, air quality, coastal 

infrastructure, and public health. 

California has a long history of studying the potential impacts of climate change on the 

State’s natural resources and economy. In 2005, Executive Order S-3-05 established 

GHG targets for the State such as: returning to year 2000 emission levels by 2010; 

1990 levels by 2020; and 80 percent below 1990 levels by 2050. The Executive Order 

also requires biennial reports on progress toward meeting those targets and updates on 

the impacts of global warming on California. The Climate Action Team produced its first 

Assessment Report in March 2006. The second assessments report (CAT 2010) 

provides the most comprehensive review and analysis of climate change modeling for 

California to date. This study is also the first state-level evaluation of both the physical 

and economic consequences from potential future climate change.

Through its reliance on peer-reviewed scientific studies, the 2010 CAT report provides 

strong evidence of the benefits of putting California and the world on the path to a low 

carbon future. The climate change scenarios describe changes in temperature, 

changes in precipitation patterns and water availability, and rising sea levels and altered 

coastal conditions. Each of these basic climatological changes in turn drives changes in 

natural and human systems that have the potential to alter the future of the State. 

Specific research highlights include:

Agriculture: The diversity and size of California’s agricultural sector creates unique 

opportunities and challenges in its responses to climate change. Global warming is

likely to change precipitation, temperature averages, maximums and minimums, pest 

and weed ranges, the length of the growing season, and other factors. These will all 

affect crop productivity. Lee et al.24 looked at productivity changes from 1950–2099 for 

seven annual field crops: alfalfa (hay), cotton, maize, winter wheat, tomatoes, rice, and 

sunflower. Compared to 2000, in 2050 cotton, maize, sunflower, and wheat yields 

decrease from 3 percent to 8 percent, while rice and tomato yields were essentially the 

same. Alfalfa yields increased, but the results were not consistent across counties. 

However, by the end of the century, yields of all crops except alfalfa decreased, and the 

differences between high- and low-GHG emissions scenarios were pronounced. The 

results suggest that climate change will decrease annual crop yields in the long-term, 

particularly for cotton, unless future climate change is minimized and/or adaptation of 

management practices and improved cultivars becomes widespread.

Extreme events may be among the greatest challenges, as they can lead to large 

losses. Since 1980, nighttime temperature has increased about three times as much as 

daytime temperature, and in some areas there has been a reduction in yield for wheat, 

maize, and barley. If the climate shifts toward a severe drought, not only will more 

irrigation be needed, but also the snow pack at higher elevations will be lacking. This 

 24 Lee, J., S. De Gryze, J. Six. (2009). Effect of Climate Change on Field Crop Production in the Central Valley of 

California. California Energy Commission. CEC-500-2009-041-F. http://www.energy.ca.gov/2009publications/CEC500-2009-041/CEC-500-2009-041-F.PDF 
Page 92

can be disastrous for producers that grow fruit trees and vines that will require years to 

reestablish production. By the end of the century modeling predicts that yields of almost 

all high value crops studied will decrease.

Forestry: California timber production has been declining over the past few decades 

due to several factors, including moderate warming, increased wildfires, land use 

change and growing emphasis on recreation. Climate change has the potential to 

further affect the extent of forests, the amount of timber production in the State and the 

value of timber on the market. The long-term increase in fire occurrence associated 

with GHG emissions is substantial, as well as an increased estimated burned area in 

California. Westerling et al.25 constructed a statistical model of wildfire as a function of 

climate and land surface characteristics in California. Model results suggest increases 

in wildfire, although the range of outcomes is large and expands with time. The longterm increase in fire occurrence associated with the higher GHG emissions pathway is 

substantial, with increases statewide ranging from 58 percent to 128 percent by 2085. 

Likewise, estimated burned area increased 57 percent to 169 percent.

Water Resources: The Sierra Nevada snowpack is California’s main water reservoir, 

and higher temperatures equate to more rain and less snow. The high elevation 

snowpack serves as a natural reservoir that stores fresh water during the wet, cold 

season and releases it gradually during the dry, warm season. About 60% of the water 

supply for Southern California comes from melting Sierra Nevada snowpack. The State 

may be facing a future with as much as 70 to 90% reduction in the Sierra Nevada snow 

pack. Snowmelt also affects hydropower generation in California (Vicuña et al.26). The 

impact of global warming on the Sierra Nevada snowpack has become one of the 

leading topics in the regional climate change studies for the California region. 

Hadley et al.27 examined the concentration of BC aerosols in snow in California and the 

potential of these aerosols to reduce albedo and increase melt. This study provides one 

of the first direct measurements for the efficient removal of black carbon from the 

atmosphere by snow and its subsequent deposition to the snow packs of California. 

The data reveal that BC concentrations in the Sierra Nevada snowpack are sufficient to 

perturb both snow melt and surface temperatures.

California’s water delivery and usage is delicately balanced. Any major changes in 

rainfall, snowpack, and timing would have serious ramifications. For instance, climate 

change would result in the need for more irrigation coming from a less reliable water 

supply. The reliability of the State Water Project and federal Central Valley Project 

water supply systems are expected to be reduced, so without changes in operating 

 25 Westerling, A.L., B. P. Bryant, H.K. Preisler, H G. Hidalgo, and T. Das. 2009. Climate Change, Growth, and 

California Wildfire. California Energy Commission. CEC-500- 2009-046-F. 

http://www.energy.ca.gov/2009publications/CEC-500-2009-046/CEC-500-2009-046-F.PDF 26 Vicuna, S., R. Leonardson, M. Hanemann, L. Dale, and J. Dracup. 2008. “Climate change impact on high elevation 

hydropower generation in California's Sierra Nevada: A case study in the upper American River.” Climatic Change 

87:S123–S137. 27 Hadley, O. L., Corrigan, C. E., Kirchstetter, T. W., Cliff, S. S., and Ramanathan, V. (2010). Measured black carbon 

deposition on the Sierra Nevada snow pack and implication for snow pack retreat, Atmos. Chem. Phys., 10, 7505-

7513, doi:10.5194/acp-10-7505.
Page 93

rules, gains in efficiency, and expanded infrastructure, the statewide water supply 

systems could be severely affected.

Coastal Areas: Sea level rise is one of the most obvious and severe impacts of a 

warming world, leading to displacement of human populations and severe economic 

impacts. As global warming continues, California’s coastal regions will be increasingly 

threatened by more intense storms and warmer water temperatures. Many of the areas 

indicated as vulnerable to sea water inundation are presently behind levees and would 

be inundated if those levees breached or were overtopped. Other areas with critical 

infrastructure, such as the San Francisco and Oakland airports, would need levee 

protection.

Energy: Anticipated climate change will affect residential electricity demand patterns 

for California's households. On average, statewide electricity demand in the residential 

sector may increase by about 7% in the next few decades solely due to increases in 

mean temperature and frequency of extreme heat events from climate change. These 

changes represent substantial impacts to California’s residents and an added stress to 

the electricity generating sector. California’s water and hydropower energy resources 

are also vulnerable to climate change. Changes in precipitation amount or pattern will 

have a direct impact on hydropower generation. If snowpack decreases, hydropower 

generation during these months would be reduced.

Air Quality: Californians experience – on a cumulative basis – the worst air quality in 

the nation. Ozone and particulate matter are the pollutants of greatest concern, and 

climate change could slow progress toward attainment of health-based air quality 

standards and increase pollution control costs by increasing the potential for high ozone 

and high particulate days. Reductions needed to counter man-made and natural 

biogenic emissions will be particularly important during strengthened temperature 

inversion events and summertime stagnation episodes. By 2050, the effects of climate 

change may partially or completely offset the benefits of emission control programs on 

ambient levels of ozone. This offsetting of air quality improvements by climate changeinduced temperature and emission changes has been termed the “climate penalty.”

Public Health: Climate change has the potential to significantly impact the health of 

Californians. Climate change may alter the frequency, timing, intensity, and duration of 

extreme weather events (meteorological events that have a significant impact on local 

communities). Injury and death are the direct health impacts most often associated with 

natural disasters. Research suggests that the most serious health effects will not be 

primarily related to changes in average climate, but rather to increased frequency of 

extreme conditions, principally more frequent, longer, and more intense heat waves. 

Studies of heat waves in urban areas have shown an association between increases in 

mortality and increases in heat, measured by maximum or minimum temperature, heat 

index (a measure of temperature and humidity), or air-mass conditions. Heat wave 

conditions are also associated with weather patterns conducive to increased air 

pollution formation (such as tropospheric ozone) and wildfire outbreaks, both of which 

pose risks to public health. In addition, climate change has the potential to influence 
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asthma symptoms, the incidence of infectious disease, and the potential to affect 

humans indirectly through impacts on food and water supplies and quality.

Ecological Impact: Climate change could have an impact on many of California's 

species and ecosystems. Several studies have shown that the relatively minor changes 

in climate in the 20th century are already having noticeable ecological impacts. Climate 

change is affecting U.S. biodiversity and ecosystems, and it is very likely that climate 

change will increase in importance as a driver for changes in biodiversity over the next 

several decades. Persistent changes in tree mortality rates can alter forest structure, 

composition, and ecosystem services such as carbon sequestration.

Economic Impacts: By putting a dollar value on the physical impacts of climate 

change, the 2009 CAT report examines in economic terms the cost associated with 

climate change if no corrective actions are taken. These assessments are in the early 

stages of development and are expected to evolve as improved data and methods are 

developed. This current assessment demonstrates that climate change poses 

significant financial risks for California, indicating that the value of reducing global 

emissions is substantial. The potential economic losses highlight the need for effective 

adaptation policies as part of the State’s response to climate change.

• Climate change could result in an overall decline in the value of harvested timber, 

with decreases between 4.9% and 8.5% in the State.

• Net economic loss for the water delivery system due to climate change is 

predicted to be between $140 and $400 million annually by the end of the 

century. 

• The costs of replacing property at risk of coastal flooding or protecting vulnerable 

areas are estimated to be at least $100 billion and $14 billion, respectively. 

• Total incremental annual electricity expenditures in the residential sector, due 

solely to climate change, range from $3.5 to $15 billion. Hydropower generation 

in California comes from units associated with relatively large reservoirs (lowelevation units) and units in high-elevations. Total annual generation is a strong 

function of the amount of precipitation falling in California. For high-elevation 

hydropower units, up to 20% decreases in annual electricity generation would 

translate to an annual loss of about $1 billion. 

• Economic impacts assessments on the environment under different climate 

scenarios are still in its infancy. For example, projected economic effects due to 

changes in above-ground carbon stock vary greatly, depending on many factors 

such as temperature increases, forest fires, development, and a future carbon 

price.

In summary, abundant evidence now shows that climate change is not just a future 

problem, but is already observable now, with measurable impacts for the state’s 
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citizens, natural resources, and economic sectors. The emerging projections of climate 

change impacts offer several sobering conclusions. In areas such as sea level rise and 

carbon emissions, recent scientific progress suggests that impacts are likely to be more 

severe than previously anticipated. Moreover, climate change impacts will not occur in 

isolation from other global environmental and societal changes, but will compound 

underlying environmental and economic stresses that are already occurring in California 

from development and urbanization. In addition, impacts that may occur in distant 

places can impact California through physical transport, such as air pollution from Asia, 

or via societal and economic interactions.

California’s position as a national leader of state-sponsored climate change research 

provides us a unique perspective on how to best prepare for the effects of climate 

change. Future considerations should recognize that current emissions have committed 

the State to some amount of ongoing and irreversible climate change. The 

consequences of taking no action on adaptation and mitigation would be costly for 

California and the world.

1.6. Abrupt Climate Change

When most people think about climate change, they imagine gradual increases in 

temperature and only marginal changes in other climatic conditions, continuing 

indefinitely or even leveling off at some time in the future. It is assumed that human 

societies can adapt to gradual climate change. However, recent climate change 

research has uncovered a disturbing feature of the Earth's climate system: it is capable 

of sudden, violent shifts. This is a critically important realization. Climate change will 

not necessarily be gradual, as assumed in most climate change projections, but may 

instead involve relatively sudden jumps between very different states. A mounting body 

of evidence suggests that continued GHG emissions may push the oceans past a 

critical threshold and into a drastically different future. 

Change in any measure of climate or its variability can be abrupt, including a change in 

the intensity, duration, or frequency of extreme events. For example, single floods, 

hurricanes, or volcanic eruptions are important for humans and ecosystems, but their 

effects generally would not be considered abrupt climate changes. A rapid, persistent 

change in the number or strength of floods or hurricanes might, however, be an abrupt 

climate change. Societies have faced both gradual and abrupt climate changes for 

millennia and have learned to adapt through various mechanisms, such as developing 

irrigation for crops, and migrating away from inhospitable regions. Nevertheless, 

because climate change will likely continue in the coming decades, denying the 

likelihood or downplaying the relevance of past abrupt events could be costly. 

Evidence from the geologic past suggests that very abrupt climatic and environmental 

changes can happen, and that these abrupt changes are more likely the more a system 

is pushed out of its dynamic equilibrium. This is currently occurring with the climate as 

a result of anthropogenic forcing and there is considerable concern in the scientific 

community that abrupt changes—imaginable, but not predictable at present—may occur 
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again. Thus, in addition to the gradual (albeit accelerated) climate changes projected 

by current climate models, Californians need to be aware of the possibility of much 

more sudden climate shifts. These shifts have a scientifically well-founded place among 

the possible futures facing the State and should be among the possibilities 

accommodated in planning and adaptation measures. The social and economic costs 

of such abrupt changes have not been assessed but may be beyond the capacity of 

many communities to absorb without major suffering28.

1.7. Summary

Climate change is a long-term shift in the climate of a specific location, region or planet. 

The shift is measured by changes in features associated with average weather, such as 

temperature, wind patterns, and precipitation. Available scientific evidence strongly 

supports the conclusion that most of the increased average global temperatures since 

the mid-20th century is very likely due to human-induced increases in GHG 

concentration. The burning of fossil fuels emits GHGs into the atmosphere, while 

deforestation and land-use changes remove trees and other kinds of vegetation that 

store (“sequester”) carbon dioxide.

Global warming is no longer a matter of the future or of places far away. Rather, 

climate change is already evident in California, and it is happening now. Climate change 

is a critical issue facing California’s citizens, ecosystems, and economic vitality. Sea 

levels have risen by as much as seven inches along the California coast over the last 

century, increasing erosion and pressure on the State’s infrastructure, water supplies, 

and natural resources. California is the only state that relies to such a great degree on 

water supply and storage in our snowpack. The State has also seen increased average 

temperatures, more extreme hot days, fewer cold nights, a lengthening of the growing 

season, shifts in the water cycle with less winter precipitation falling as snow, and both 

snowmelt and rainwater running off sooner in the year. These climate driven changes 

affect resources critical to the health and prosperity of California. For example, forest 

and wild-land fires are becoming more frequent and intense due to dry seasons that 

start earlier and end later. Agriculture is especially vulnerable to altered temperature 

and rainfall patterns, and new pest problems. Economic evaluations of potential 

impacts due to climate change show that climate change could impose substantial costs 

to Californians on the order of tens of billions of dollars per year. 

The emerging projections of climate change impacts offer several sobering conclusions. 

In areas such as sea‐level rise and carbon emissions, recent scientific progress 

suggests that impacts are likely to be more severe than previously anticipated. The 

preceding section has focused on the ways in which changes in climate are projected to 

affect the environment and society though the 21st century. However, what will actually 

occur depends greatly on efforts to reduce emissions and to minimize future negative 

impacts. In short, human decisions are key to determining the true severity of future 

 28 The future is now: An update on climate change science impacts and response options for California (2008). 

Publication # CEC-500-2008-071.

http://www.energy.ca.gov/2008publications/CEC-500-2008-071/CEC-500-2008-071.PDF
Page 97

impacts. California has already demonstrated the enormous potential for positive 

change. Mitigation of emissions to slow down climate change and efforts in adaptation 

to deal with the impacts of change will help minimize the harmful impacts of climate 

change and provide valuable co‐benefits.

2. NATIONAL GREENHOUSE GAS PROGRAM DEVELOPMENT

In May of 2010, USEPA finalized its GHG emission standards for light-duty vehicles for 

model year 2012-2016 vehicles. This national program will implement footprint-indexed 

standards for all cars and light trucks sold in the U.S., with a projected fleet average

model year 2016 requirement of 250 grams of carbon dioxide emissions per mile.29 The 

2016 federal endpoint is nearly identical to the precedential California 2009-2016 

standards and extends California’s promotion of lower GHG technologies (e.g., for 

engines, transmission, and air-conditioning technologies) nationwide to achieve a 

similar 2016 new vehicle fleet outcome. This initial national GHG program was 

developed by USEPA, in coordination with NHTSA, which administers Corporate 

Average Fuel Economy (CAFE) Standards. The national 2012-2016 program was the 

subject of commitment letters from the State of California and major automakers. As a 

result, ARB modified its regulations to explicitly accept federal compliance with the 

USEPA standards as sufficient to demonstrate compliance with California’s standards 

for the 2012-2016 model years.

Also in May of 2010, a Presidential Memorandum directed USEPA and NHTSA to work 

jointly to develop continuing GHG standards for model years 2017-2025 (USEPA and 

NHTSA, 2011a). The Memorandum requested that USEPA and NHTSA work closely 

with ARB on a 2010 technical assessment that would assess technologies and costs to 

achieve varying levels for GHG emission reduction through model year 2025. The 

result was a September 2010 Interim Technical Assessment Report, jointly authored by 

USEPA, NHTSA, and ARB. Subsequent to that collaborative technical work, ARB staff 

has closely monitored the work of USEPA and NHTSA, the staffs continued to jointly 

hold meetings with various stakeholders (e.g., individual automakers), examine updated 

technical materials, and develop consistent technology assumptions. In November 

2011, USEPA and NHTSA proposed 2017-2025 federal standards (USEPA and 

NHTSA, 2011b).

3. SUMMARY OF PROPOSED REGULATION

In this section III.3, a summary of the proposed standards and major provisions is 

provided. After this summary section, the technical feasibility basis for the standards is 

described in section III.4, while a more thorough description and assessment of

compliance with the proposed standards is shown in section III.5.

3.1. Pollutants Included in the Proposed Regulation

 29 For the national GHG program page see USEPA’s Office of Transportation and Air Quality, “Regulations and 

Standards.” http://www.epa.gov/otaq/climate/regulations.htm
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The proposed regulation sets emission standards for CO2, CH4, and N2O, and provides 

credits toward the CO2 standard if a manufacturer reduces refrigerant emissions from 

the vehicle’s air conditioning system. 

3.2. Footprint-Indexed Greenhouse Gas Emission Standards

The proposed greenhouse gas (GHG) emission standards would reduce new light-duty 

carbon dioxide (CO2) emissions from their regulatory model year 2016 levels by 

approximately 34% by model year 2025, from about 251 to about 166 gCO2/mile, based 

on the projected mix of vehicles sold in California. The basic structure of the standards 

includes two categories – passenger cars and light-duty trucks – that are consistent with 

federal categories for light-duty vehicles. The standard targets would reduce car CO2

emissions by about 36% and truck CO2 emissions by about 32% from model year 2016 

through 2025. Figure III-A-3-1 illustrates the basic target emission trends that are 

projected from the car and truck standards.

Figure III-A-3-1. Target emission reductions from GHG standards

Within the two categories, the CO2 standard targets for vehicle models sold by each 

automaker are indexed to the vehicles’ footprint, which is calculated as each vehicle 

model’s wheelbase times the average track width. As a result of the proposed 

regulatory structure, the precise CO2 emission rates that will result from the standards 

in each year from 2017 through 2025 will depend on the ultimate sales-weighted mix of 

vehicles (i.e., according to vehicle sales in each category and the footprint of the 

models) sold in each year. Figure III-A-3-2 illustrates model year 2008 vehicle models, 

the 2016 standard targets (which overall are approximately 25% below model year 2008 

vehicles), and the 2025 standard targets (which overall are about 34% below the 2016 

targets). The combined result of the 2012-2016 standards and the 2017-2025 

standards would reduce vehicle CO2 emissions by approximately 51% from their 2008 

levels.
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Figure III-A-3-2. Illustration of 2025 car and truck standard GHG targets compared to the 

2008 fleet and 2016 standard targets

Table III-A-3-3 shows the year-by-year new vehicle CO2 reductions that are projected 

as a result of the standards from cars, light-duty trucks, and combined light-duty 

vehicles. The projected result overall from 2016-2025 from these standards is to reduce 

car CO2 emissions by approximately 4.9%/year, reduce truck CO2 emissions by 

approximately 4.1%/year, and reduce combined light-duty CO2 emissions by 

approximately 4.5%/year from 2016 through 2025. These CO2 emission reduction 

estimations are approximate because the required emission level to achieve compliance 

with the standards for each vehicle manufacturing company depends on their ultimate 

sales mix of vehicles.
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Table III-A-3-3. Projected targets for light-duty vehicle gCO2/mile emission rates

Model Car Truck Combined light-duty

year gCO2/mi Annual 

change gCO2/mi Annual change gCO2/mi Annual change

Baseline 2008 291 396 336

2009-2011 

2012 263 340 290

Previous 2013 256 2.8% 330 2.8% 283 2.6%

Rule Targets 2014 248 3.3% 321 2.8% 275 2.8%

2015 236 4.5% 306 4.5% 263 4.3%

2016 226 4.5% 292 4.5% 251 4.4%

2017 213 5.5% 290 0.7% 243 3.2%

2018 203 4.9% 280 3.5% 233 4.2%

Proposed 2019 192 5.2% 273 2.8% 224 4.0%

Rulemaking 2020 183 4.9% 264 3.0% 215 3.9%

Targets 2021 173 5.5% 245 7.5% 201 6.3%

2022 165 4.4% 233 4.9% 192 4.6%

2023 158 4.5% 221 4.9% 183 4.8%

2024 151 4.5% 210 5.0% 174 4.8%

2025 144 4.6% 200 4.9% 166 4.8%

Average change, (2016-2025) 4.9% 4.1% 4.5%

Change, 2008-2016 -23% -26% -25%

Change, 2016-2025 -36% -32% -34%

Change, 2008-2025 -51% -50% -51%

Notes: Car, truck, overall targets shown are based on projected sales of vehicles by footprint, category (ultimate gCO2/mile 

levels are determined by end-of-year sales); the original California GHG standards for model years 2009-2011 are based on 

a different two-category system (PC/LDT1 and LDT2) than the car and truck system of the 2012-2016 federal standards and 

proposed 2017-2025 standards; Difference of individual columns may not match due to rounding.

Proposed standards also apply to other greenhouse gases, in particular CH4, and N2O. 

In addition, reductions in high global warming potential refrigerant emissions (e.g., 

vehicle refrigerant HFC-134a) create a credit expressed in CO2-equivalents. In the 

current 2009 to 2016 ARB GHG standards, CH4 and N2O emissions are converted to 

CO2-equivalents, and included in the calculation used to determine compliance with the 

CO2 standard. USEPA, in their 2012-16 standards, adopted separate standards for 

CH4 and for N2O. Both approaches account for the principal GHGs emitted by 

passenger motor vehicles, reflecting the purpose and intent of the respective regulatory 

programs to control GHG air pollutants.

For the 2017-2025 model year standards, ARB proposes to use the USEPA approach 

and adopt separate standards for CO2, CH4, and N2O. The CH4 and N2O standards 

will reflect the same stringency as the prior, separate federal standards. This revised 

approach avoids having to adjust the CO2 footprint curves to reflect the other two 

pollutants. Crediting for reductions in high global warming refrigerant emissions will 

continue similar to the current regulations, and staff intends that both ARB and USEPA 

regulations will use the same credit values. Additional discussion of the CH4 and N2O 

standards appears later in this report. The net result is that, like the current 2009-2016 

California GHG standards, the proposed 2017-2025 standards account for all major 

sources of vehicle GHG emissions, including upstream GHG emissions associated with 

the production and transportation of various vehicle fuels. Again, the purpose and intent 

is to account for and seek reductions in GHG air pollutants.
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3.3. Flexibilities and Alternative Compliance Mechanisms

The two primary flexibilities of the standards are to allow a fluctuation of the future new 

vehicle fleet’s CO2 emissions according to each company’s car-truck composition and 

sales-weighted sales according to vehicle footprint. These primary flexibilities were 

deemed critical to allow the standards to accommodate a diverse fleet of vehicle types 

and their potential to shift according to consumer trends, fluctuating fuel prices, and 

other factors. Beyond these fleet-accommodating features, many of the flexibilities from 

the model year 2016 standards will continue. For example, regulated companies are 

allowed averaging, banking (5-year credit carry-forward, 3-year credit carry-back), 

trading between car and truck categories, and trading between companies. 

In addition, a number of other crediting mechanisms are provided. Crediting for more 

efficient systems, lower-refrigerant leakage designs, and alternative low-global-warming 

potential refrigerants are provided for innovations in vehicle air conditioning systems. 

Off-cycle credits are permitted for verifiable GHG emission-reduction technologies that 

are not fully accounted for with the established regulatory test cycle procedure. Also, 

special crediting is provided for alternative fuel vehicles for which there are no direct 

tailpipe exhaust CO2 emissions.

4. TECHNOLOGICAL FEASIBILITY OF PROPOSED STANDARDS

4.1. Background

The proposed standards continue California’s original “Pavley” standards that were 

developed in 2003-2004 in response Assembly Bill 1493 of 2002, as well as implement 

AB 32. Since adoption of the original California 2009-2016 standards, California has 

deemed automaker compliance with the similar federal 2012-2016 GHG standards, 

promulgated by the U.S. Environmental Protection Agency (USEPA) in 2009, to suffice 

for compliance with California standards for those model years. 

Since federal adoption of GHG standards in 2009, the federal government and the

California Air Resources Board have been jointly engaged in extensive analysis and 

technical collaboration with automobile manufacturers and suppliers. The joint work 

between USEPA, NHTSA and ARB has ensured that the utmost technical knowledge is 

jointly held and deliberated among the technical staffs of the three agencies, that the 

agencies’ develop regulations that are harmonized in terms of their stringency and basic 

provisions, and that the standards are consistent with the regulatory authority of all 

three agencies. In addition, the joint work has sought to ensure that California 

maintains and preserves its leading role in forcing technology to meet passenger 

vehicle emission reduction standards, accepting National Program compliance only if 

those standards achieve the type of federally unprecedented, substantial emission 

reductions envisioned by the President’s announcement and the newly proposed 

standards (USEPA and NHTSA, 2011a; 2011b).
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The joint agency technical efforts have involved four public technical workshops that 

spanned topics of efficiency, mass-reduction, and safety technology; collaborative 

technical contract work (e.g., with FEV, Ricardo, Lotus); hundreds of internal jointagency meetings; and dozens of agency-automaker meetings. A major milestone in the 

technical work was the Interim Technical Assessment Report (or “TAR”), finalized by 

USEPA, NHTSA, and ARB in September 2010. This TAR, in turn, further encouraged

greater technical collaboration between the agencies, automobile companies, 

automotive suppliers, and other stakeholders. 

4.2. Technology Assessment

The standards are predicated on many existing and emerging technologies in vehicles 

that increase engine and transmission efficiency, reduce vehicle energy loads, improve 

auxiliary and accessory efficiency, and that could increasingly electrify vehicle 

subsystems with hybrid and electric drivetrains. Previous rulemakings (i.e., California’s 

2009-2016 and federal 2012-2016 standards) established an original technical basis for 

GHG standards that is bearing out in practice, as manufacturers have met their GHG 

requirements in California for the 2009 and 2010 model years, and appear to be well on 

track for 2011. This rulemaking builds on this existing technical foundation with new 

technical data and understanding of evolving state-of-the-art engine, transmission, 

hybrid, and electric-drive technologies.

Table III-A-4-1 shows an illustrative summary of technologies with high potential for CO2

emission reduction along with their adoption within the 2008 fleet. As suggested by the 

summary table, there are many individual technologies available with substantial CO2

reduction potential. The listed technologies can each have many different 

configurations, varying CO2 potential, and differing applicability across different vehicle 

types. As shown in the table, many of the technologies have, up to now, only seen 

limited deployment in new vehicle models in the fleet. It must be remembered, 

however, that the Pavley standards are only halfway implemented, with at least four full

model years remaining to increase deployment. 
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Table III-A-4-1. Emerging technologies’ CO2 reduction potential and current adoption

Area Technology or mechanism for CO2 reduction Potential CO2

reduction

Share, 

MY2008

Share, 

MY2010 

Variable valve timing 2-8% 53% 86%

Cylinder deactivation 3-6% 7% 7%

Turbocharging 2-5% 3% 3%

Engine Gasoline direct injection 8-15% 2% 9%

Powertrain Compression ignition diesel 15-40% 0.1% 0.5%

Digital valve actuation 5-10% 0% 0%

6+ speed 3-5% 21% 40%

Transmission Continuously variable 6-11% 8% 10%

Dual-clutch, automated manual 4-13% 1% -

Aerodynamics 5-8% - -

Tire rolling resistance 2-8% - -

More efficient auxiliaries (steering, air cond., alternator) 2-10% - -

Lower refrigerant emissions (low-leak, low-GWP) 2-10% - -

Vehicle Mass-reduction Advanced material component 5-10% - -

Integrated vehicle design 10-20% - -

Hybrid systems Stop-start mild hybrid 5-25% <1% <1%

Full hybrid electric system 20-50% 2% 4%

Electric-drive Plug-in capable electric vehicles 30-100% 0% 0%

Fuel cell vehicles 30-100% 0% 0%

“ – ” indicates technologies areas where available deployment share estimates are not available; Sources: 

USEPA and NHTSA, 2010; USEPA, NHTSA, CARB, 2011; NRC, 2011; Ricardo, 2011; USEPA, 2010

The above table offers an illustrative summary of the CO2 potential – but the modeling 

efforts to analyze the potential of technologies required specific identification of the 

engineering capabilities of particular technologies for deployment on various vehicle 

classes. The following tables identify technologies that were investigated for their 

potential adoption within the 2025 timeframe of this rulemaking. The following 

technology description tables are separated as follows:

• Vehicle road load and accessory energy reduction (Table III-A-4-2)

• Engine efficiency technology (Table III-A-4-3)

• Transmission efficiency technology (Table III-A-4-4)

• Hybrid efficiency technology (Table III-A-4-5)

• Electric drive technology (Table III-A-4-6)

• Air conditioning system technology (Table III-A-4-7)

Vehicle road load and accessory energy reduction: There are a number of 

technologies that reduce the overall energy loads on the vehicle to thereby result in 

reductions in overall vehicle tailpipe CO2 emissions. There are a number of auxiliary, 

ancillary, and parasitic energy losses within the vehicle. Some of these energy losses, 

for example from power steering, alternator efficiency losses, water pumps, and cooling 

fans, all offer potential efficiency improvements. Larger in magnitude is the potential 

CO2-reduction from reducing the overall physical energy requirement to propel the 

vehicle forward. The ultimate energy requirement of the vehicle is the energy load 

required at the motive wheel to overcome aerodynamic drag, tire rolling resistance, 

inertial acceleration, and grade. These energy loads can be reduced with improved 
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aerodynamic design, tires with lower rolling resistance, and mass reduction through 

advanced materials and optimized vehicle design. 

Table III-A-4-2. Vehicle load reduction and accessory improvements investigated for 

potential CO2 reduction

Low-rolling-resistance tires (ROLL) - have characteristics that reduce frictional losses associated with the energy 

dissipated in the deformation of the tires under load, thereby reducing fuel use and CO2 emissions.

Low-drag brakes (LDB) - reduce the sliding friction of disc brake pads on rotors when the brakes are not engaged 

because the brake pads are pulled away from the rotors. 

Front or secondary axle disconnect for four-wheel drive systems (SAX) - provides a torque distribution disconnect 

between front and rear axles when torque is not required for the non-driving axle, reducing associated parasitic energy 

losses. 

Aerodynamic drag reduction (AERO) - This can be achieved via two approaches, either reducing the drag coefficients 

or reducing vehicle frontal area. To reduce drag coefficients, skirts, air dams, underbody covers, and more aerodynamic 

side view mirrors can be applied. In addition to the standard aerodynamic treatments, the agencies have included a 

second level of aerodynamic technologies which could include active grille shutters, rear visors, and larger under body 

panels. 

Electric power steering (EPS)/ Electro-hydraulic power steering (EHPS) - is an electrically-assisted steering system 

that replaces a continuously operated pump of traditional hydraulic power steering, thereby reducing parasitic losses from 

the accessory drive. 

Improved accessories (IACC) - may include high efficiency alternators, electrically driven (i.e., on-demand) water pumps 

and cooling fans. This excludes other electrical accessories such as electric oil pumps and electrically driven air 

conditioner compressors. 

Mass Reduction (Mass) - This technology includes material substitution, smart design, and mass reduction 

compounding. The actual amount of reduction from the 2008 baseline was determined based on confidential business 

information from vehicle manufacturers, material suppliers, existing studies in the literature, and NHTSA/USEPA/ARB 

assessment of the levels of mass reduction that are both technologically feasible and can be implemented reasonably 

safely.

Engine efficiency technology: Often considered the most fundamental aspect of 

vehicle efficiency and tailpipe CO2 emissions is the vehicle’s central power source, the 

internal combustion engine. The engine has considerable opportunities for energy 

efficiency improvement by reducing engine pumping losses due to the movement of

intake and exhaust gases, friction losses from moving parts, thermodynamic efficiency 

losses, and exhaust heat losses. Substantial improvements from low-viscosity 

lubrication and engine friction reduction improvements can reduce friction losses. 

Improved valvetrain systems that offer increased engine control with cam phasing and 

variable valve lift help enable independent valve timing, thermodynamic efficiency, and 

further engine improvements. Digital valve actuation (either electronically or electrohydraulically actuated) offers the ability to partially or fully eliminate camshafts (and 

associated losses) and enable improved controls for cam phasing and lift, as well as 

cylinder deactivation. The use of cam phasing, turbocharging, engine downsizing, 

gasoline direct injection and higher compression ratios allows for reduced pumping 

losses and higher thermodynamic efficiency, for an expanded operating zone of low fuel 

consumption and low CO2 emissions. A further advancement in downsized 

turbocharged direct injection engines is to introduce high amounts of recirculated 

exhaust gas – cooled before mixing with intake air – with further boosting to reduce 

pumping losses, reduce friction loss, and reduce exhaust heat loss.
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Table III-A-4-3. Engine efficiency technologies investigated for potential CO2 reduction

Low-friction lubricants (LUB) - low viscosity and advanced low friction lubricants oils are now available with improved 

performance and better lubrication. If manufacturers choose to make use of these lubricants, they would need to make 

engine changes and possibly conduct durability testing to accommodate the low-friction lubricants. 

Reduction of engine friction losses (EFR) - can be achieved through low-tension piston rings, roller cam followers, 

improved material coatings, more optimal thermal management, piston surface treatments, and other improvements in the 

design of engine components and subsystems that improve engine operation. 

Cylinder deactivation (DEAC) - deactivates the intake and exhaust valves and prevents fuel injection into some 

cylinders during light-load operation. The engine runs temporarily as though it were a smaller engine, substantially 

reducing pumping losses. 

Variable valve timing (VVT) - alters the timing of the intake valve, exhaust valve, or both, primarily to reduce pumping 

losses, increase specific power, and control residual gases. Two forms: dual cam phasing (DCP) and coupled cam 

phasing (CCP)

Discrete variable valve lift (DVVL) - increases efficiency by optimizing air flow over a broader range of engine operation 

which reduces pumping losses. Accomplished by controlled switching between two or more cam profile lobe heights.

Continuous variable valve lift (CVVL) - is an electromechanical or electrohydraulic system in which valve timing is 

changed as lift height is controlled. This yields a wide range of performance optimization and volumetric efficiency, 

including enabling the engine to be valve throttled. 

Digital valve actuation (dVA) – involves electromagnetic or electrohydraulic actuation of engine intake and exhaust 

valves, allowing for potential elimination of camshafts and associated efficiency losses. This provides greater 

independent control of cam phasing and lift for improved optimization of engine operation.

Stoichiometric gasoline direct-injection technology (SGDI) - injects fuel at high pressure directly into the combustion 

chamber to improve cooling of the air/fuel charge within the cylinder, which allows for higher compression ratios and 

increased thermodynamic efficiency. 

Turbocharging and downsizing (TBDS) - increases the available airflow and specific power level, allowing a reduced 

engine size while maintaining performance. Engines of this type use gasoline direct injection (GDI) and dual cam 

phasing. This reduces pumping losses at lighter loads in comparison to a larger engine. 

Turbocharging and downsizing with cooled exhaust-gas recirculation (EGR) - additional charge dilution reduces the 

incidence of knocking combustion and obviates the need for fuel enrichment at high engine power. This allows for higher 

boost pressure and/or compression ratio and further reduction in engine displacement and both pumping and friction 

losses while maintaining performance. Engines of this type use GDI and both dual cam phasing and discrete variable 

valve lift. The EGR systems considered in this assessment would use a dual-loop system with both high and low 

pressure EGR loops and dual EGR coolers. The engines would also use single-stage, variable geometry turbocharging 

with higher intake boost pressure available across a broader range of engine operation than conventional turbocharged SI 

engines. 

Diesel engines - have several characteristics that give reduced CO2 emissions and lower fuel use, including reduced 

pumping losses due to lack of (or greatly reduced) throttling, and a combustion cycle that operates at a higher 

compression ratio and with a very lean air/fuel mixture relative to an equivalent-performance gasoline engine. This 

technology requires additional enablers, such as a NOx adsorption catalyst system or a urea/ammonia selective catalytic 

reduction system for control of NOx emissions during lean (excess air) operation. For purposes of this technical 

assessment, due to insufficient time, we have not included advanced diesel engines in our modeling scenarios. This does 

not mean that the agencies do not see a role for diesels in the future fleet since we fully expect some manufacturers will 

rely on diesels as part of their future strategy. 

Transmission efficiency technology: Transmission technologies are fundamental in 

efficiently transferring engine torque at variable speeds to the wheels. In terms of

overall vehicle efficiency, transmission technology is also critically important in allowing 

the operation of the engine in its lowest fuel consumption operating points more 

frequently. More gears (perhaps up to 8-speeds or more), closer gear ratio spacing, 

and optimized controls that put and keep transmissions and engines within their optimal 

speeds all offer increased vehicle efficiency for lower CO2 emissions. Dual-clutch 

transmissions allow essentially the same efficiency as manual transmissions by 

eliminating torque converter losses and allowing faster shifting between gears, including 

the pre-selection of gears.
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Table III-A-4-4. Transmission efficiency technologies investigated for potential CO2

reduction

Improved automatic transmission controls (IATC) - optimizes shift schedule to minimize fuel use and CO2 emissions 

under wide ranging conditions, and minimizes losses associated with torque converter slip through lock-up or modulation. 

Six-, seven-, eight-and nine speed automatic transmissions - the gear ratio spacing and transmission ratios are 

optimized to enable the engine to operate in a more efficient operating range over a broader range of vehicle operating 

conditions. While a six speed transmission application was most prevalent for the 2012-2016 final rule, eight speed 

transmissions are expected to be readily available and applied in the 2017 through 2025 timeframe. 

Dual clutch or automated shift manual transmissions (DCT) - are similar to manual transmissions, but the vehicle 

controls shifting and launch functions. A dual-clutch automated shift manual transmission uses separate clutches for 

even-numbered and odd-numbered gears, so the next expected gear is pre-selected, which allows for faster and 

smoother shifting. 

Continuously variable transmission (CVT) - commonly uses V-shaped pulleys connected by a metal belt rather than 

gears to provide ratios for operation. Unlike manual and automatic transmissions with fixed transmission ratios, 

continuously variable transmissions can provide fully variable and an infinite number of transmission ratios that enable the 

engine to operate in a more efficient operating range over a broader range of vehicle operating conditions. 

Manual 6-speed transmission (6MAN) - offers an additional gear ratio, often with a higher overdrive gear ratio, than a 5-

speed manual transmission. 

High-efficiency gearbox (HEG) - improves the mechanical efficiency of transferring torque from engine to axle(s).

Hybrid efficiency technology: Hybrid technology includes the use of stop-start 

capability, electric machines (with motor-assist and electric generator braking 

capability), and increased vehicle battery electric storage capability to dramatically 

improve vehicle efficiency. Hybrid technologies offer the potential for far more efficient 

use of fuel on-board the vehicle through the elimination of engine idling, reduction of 

fuel consumption during deceleration, reduction of acceleration power requirement 

through launch assist, and the recovery of vehicle energy losses through regenerative 

braking during deceleration. These energy-saving mechanisms are dependent on 

system controls that can allow for optimal utilization of the engine and/or transmission 

within certain engine operating zones. A number of hybrid architectures have emerged, 

ranging from simpler stop-start systems with some amount of launch assist, to parallel 

systems with one motor-generator and one or two clutches, to power-split systems with 

two or more electric machines.
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Table III-A-4-5. Hybrid system technologies investigated for potential CO2 reduction

12-volt micro-hybrid (MHEV) - also known as idle-stop or start-stop and commonly implemented as a 12-volt belt-driven 

integrated starter-generator, is the most basic hybrid system that facilitates idle-stop capability. This system replaces a 

common alternator with a belt-driven high-power starter-alternator, a revised accessory drive system, and an additional 

battery.

Higher Voltage Stop-Start/Belt Integrated Starter Generator (BISG) - provides idle-stop capability and uses a higher 

voltage battery with increased energy capacity over typical automotive batteries. The higher system voltage allows the 

use of a smaller, more powerful electric motor for increased launch, power assist, and regenerative braking capability. 

P2 Hybrid (P2HEV) - uses a transmission integrated electric motor placed between the engine and a gearbox or CVT 

used to decouple the motor/transmission from the engine. In addition, a P2 Hybrid would typically be equipped with a 

larger electric machine. Engaging the clutch allows all-electric operation and more efficient brake-energy recovery. 

Disengaging the clutch allows efficient coupling of the engine and electric motor and, when combined with a DCT 

transmission, reduces gear-train losses. 

2-mode hybrid (2MHEV) - is a hybrid electric drive system that uses an adaptation of a conventional stepped-ratio 

automatic transmission by replacing some of the transmission clutches with two electric motors that control the ratio of 

engine speed to vehicle speed, while clutches allow the motors to be bypassed. This improves both the transmission 

torque capacity for heavy-duty applications and reduces fuel consumption and CO2 emissions at highway speeds relative 

to other types of hybrid electric drive systems. 2-mode hybrids have not been considered in this assessment.

Power-split hybrid (PSHEV) - a hybrid electric drive system that replaces the traditional transmission with a single 

planetary gearset and a motor/generator. This motor/generator uses the engine to either charge the battery or supply 

additional power to the drive motor. A second, more powerful motor/generator is permanently connected to the vehicle's 

final drive and always turns with the wheels. The planetary gear splits engine power between the first motor/generator 

and the drive motor to either charge the battery or supply power to the wheels. Power-split hybrids have not been 

considered in this assessment.

Electric drive technology: Electric-drive vehicle technologies, including plug-in hybrid 

electric, electric, and hydrogen fuel cell, offer the most dramatic potential for CO2

reduction. These technologies offer the potential to fundamentally eliminate 

thermodynamic and other efficiency losses that are inherent to internal combustion 

engines. These technologies also offer the prospect of decoupling vehicles from GHGintensive petroleum fuels – by utilizing electricity and hydrogen fuel sourced from a 

variety of renewable and other low-GHG primary sources. 

Table III-A-4-6. Electric-drive technologies investigated for potential CO2 reduction

Plug-in hybrid electric vehicles (PHEV) - are hybrid electric vehicles with the means to charge their battery packs from 

an external electric source. These vehicles have larger battery packs with more energy storage and a greater capability 

to be discharged than other hybrid electric vehicles. They also use a control system that allows the battery pack to be 

substantially depleted under electric-only or blended mechanical/electric operation and batteries that can be cycled in 

charge sustaining operation at a lower state of charge than is typical of other hybrid electric vehicles.

Battery Electric vehicles (BEV) - are vehicles with all-electric drive and with vehicle systems powered by energyoptimized batteries charged primarily from grid electricity. BEV's with several ranges of 75-, 100-, and 150-mile real-world 

range have been included. 

Fuel cell electric vehicles (FCVs) - utilize a full electric drive platform but consume electricity generated by an on-board 

fuel cell and hydrogen fuel. Fuel cells are electro-chemical devices that directly convert reactants (hydrogen and oxygen 

via air) into electricity, with the potential of achieving more than twice the efficiency of conventional internal combustion 

engines. High-pressure gaseous hydrogen storage tanks are used by most automakers for FCVs that are currently under 

development. The high-pressure tanks are similar (but higher pressure) to those used for compressed gas storage in 

CNG vehicles worldwide.

Air conditioning system technology: Air conditioning systems have GHG emissions 

associated directly with their refrigerant and, indirectly, through air conditioning systems’ 

increased use of fuel in real-world vehicle operations. Improvements in air conditioning 

systems are not evaluated as part of the primary city-highway test cycle procedure for 

measuring CO2 emissions. With similar provisions as in the current standards, the, airconditioning technologies in the proposed standards are to be credited according to a 
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design-based approach that grants credits (based on design criteria and engineering 

data) for given systems. Air conditioning improvements are credited in three main 

areas. The first involves increased efficiency air conditioning systems that reduce 

“indirect” real-world CO2 emissions when the air conditioning system is engaged to cool 

the vehicle cabin. The second involves reduced leakage of the “direct” HFC-134a 

refrigerant emissions through less permeable systems. Finally, switching the refrigerant 

from its current HFC-134a (GWP=1430) to one with a lower global warming potential 

(e.g., HFO-1234yf with GWP=4 or CO2 with GWP=1) offers potential improvements and 

GHG-reduction credits.

Table III-A-4-7. Air conditioning system technologies investigated for potential CO2

reduction

Air conditioning efficiency (ACEff) – improve efficiency of air conditioning operation, for example, with externally 

controlled compressor, air recirculation, blower controls, electronic expansion valves, improved evaporator and 

condenser, oil separator. Technologies provided a system of credits as utilized in USEPA 2012-2016 rulemaking, up to 

approximately 5-7 gCO2e/mile for cars and trucks.

Air conditioning low refrigerant leak (LowLeak) – reduces leakage of refrigerant HFC-134a emissions with changes, 

such as low-permeability hoses and low-leak seals and connectors, as measured through SAE International’s J2727 

standard and USEPA calculation method. Technologies provided a system of credits as utilized in USEPA 2012-2016 

rulemaking, up to approximately 6-8 gCO2e/mile for cars and trucks.

Low global warming potential refrigerant replacement (GWP) – replaces conventional refrigerant HFC-134a 

(GWP=1430) with lower global warming potential refrigerants such as HFO-1234yf (GWP=4), CO2 (GWP=1), HFC-152a 

(GWP=124). Technologies are provided a system of credits as utilized in USEPA 2012-2016 rulemaking, up to 

approximately 14-17 gCO2e/mile for cars and trucks.

Combined Benefits: The combined benefits of the various CO2-reduction technologies 

must be evaluated synergistically in order to accurately account for their interactions on 

vehicles through various driving conditions. The past ARB staff 2009-2016 rulemaking 

leveraged the vehicle simulation modeling work of AVL (see NESCCAF, 2004). This 

regulatory development technical work utilizes the assessment of technology 

effectiveness from the USEPA and NHTSA 2012-2016 rulemaking and new 2010-2011 

vehicle simulation work of Ricardo. The regulatory technical work incorporates the 

state-of-the-art Ricardo data into an updated version of the USEPA Lumped Parameter 

modeling tool that includes emerging technologies and better incorporates their 

synergies per the new Ricardo results.

The Ricardo (2011) vehicle simulation study analyzed six different light-duty vehicle 

classes: subcompact car (Toyota Yaris), standard car (Toyota Camry); large car 

(Chrysler 300); small sport utility vehicle (Saturn Vue); large multi-purpose vehicle 

(Dodge Grand Caravan); and large truck (Ford F150). The technologies incorporated in 

the Ricardo modeling include most of those listed in the above tables. ARB technical 

staff collaborated with USEPA and Ricardo on the project in 2009-2010 to ensure the 

study explored the boundaries of engine, transmission, and hybrid technologies within 

the 2020-2025 timeframe.

The Ricardo data makes a number of improvements over all previous vehicle simulation 

modeling efforts for the context of this rulemaking in terms of technical rigor, technology 

relevance, technology timing, and technology data quality. The rigor of the Ricardo 
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model is reflected by Ricardo’s existing ongoing work with automotive companies to 

study potential efficiency and CO2 improvement as multiple technologies are 

synergistically applied to vehicles. The technical underpinnings of the model are well 

validated, having received advanced engine maps from lab testing and proprietary work 

with other automotive clients. The Ricardo simulation incorporates the most relevant 

emerging technologies to best reflect the likely technologies (e.g., valvetrain, fuel 

injection, transmission) that will be applied to vehicles in the 2015-2025 timeframe, 

whereas previous efforts tend to focus on vehicle technologies and data that are already 

to some extent outdated, are not being developed by automakers, and/or are not 

expected to be widely deployed in the 2025 timeframe. The Ricardo work also covers a 

wider span of vehicle classes, technology configurations, performance characteristics, 

and road load factors than previous such modeling efforts. 

A number of key technical innovations in the Ricardo modeling made it superior to 

similar previous work and the most relevant study for this proposed rulemaking. 

Compared to previous work, the Ricardo study has included cutting-edge engine 

technologies that have not otherwise been modeled comprehensively and 

synergistically on new vehicles. Such technologies include advanced turbocharged 

downsized (at 18-, 24-, and 27-bar brake mean effective pressure [BMEP]) engines with 

direct injection, as well as cooled exhaust gas recirculation. Other powertrain 

technologies that were investigated with new simulation rigor include cam-switching, 

digital valve actuation, dual-clutch transmissions, and stop-start technology. Beyond 

these advanced powertrain technologies, the new Ricardo study added technical rigor 

to its study of new parallel hybrid technology that involves a pre-transmission clutch 

(that is similar to systems being deployed by Nissan, Hyundai, and Volkswagen).

The Ricardo results involved many thousands of simulations of various technology 

configurations, across the vehicle classes, across vehicle cycles, including ability to 

scale the various road load characteristics of the vehicles. A selection of the modeling 

and analytical findings from the Ricardo vehicle simulation study are summarized here. 

The study analyzed vehicle performance characteristics in order to selectively include 

only technology configurations that offered constant (or improved) utility attributes (e.g., 

acceleration, passing, and grade performance). The Ricardo study explicitly 

investigated emerging technologies that have the potential for widespread application 

across model year 2020 models.

Ricardo advanced technology findings are compared with existing models in the 

standard car, multi-purpose vehicle, and large truck classes in the figures below. Figure 

III-A-4-1 shows the standard car Ricardo results, as compared with the modeling 

reference 2007 Toyota Camry. Several other existing models were added to the chart –

including two more recent models (2010 Toyota Camry, 2011 Hyundai Sonata with 

turbocharging and direct injection) and three existing hybrids (Toyota Camry, Hyundai 

Sonata, Ford Fusion – to show the span of more advanced existing technology. As 

depicted, the advanced powertrain options (turbocharged downsizing, stoichiometric 

GDI, cooled EGR, DCT) and road load reduction technologies (aerodynamic, tire rolling 

resistance, and mass-reduction improvements) have the potential to surpass existing 
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hybrid technology models with lower CO2 emissions and greater efficiency. As 

compared with the reference 2007 Toyota Camry, the Ricardo results suggest that 

advanced non-hybrid technology can achieve a 50% CO2 reduction and hybrid 

technology could achieve a 60% CO2 reduction. Staff notes that the following three 

figures that are based on Ricardo modeling results show the vehicle efficiency, 

measured as miles per gallon of gasoline consumed for comparison with values 

presented by Ricardo; these energy-to-CO2 relationships do not incorporate the effects 

of other regulated GHG emissions (as are assessed below).

Figure III-A-4-1. Ricardo (2011) mid-size sedan results versus existing models

Note: Figure does not include non-CO2 GHG emissions

The Ricardo results exhibited similar technology potential findings for the multi-purpose 

vehicle class, as shown in Figure III-A-4-2. From the reference 2007 Dodge Grand 

Caravan, substantial CO2 reduction potential was found with the utilization of engine, 

transmission, and road load reduction technologies. For example, with the application 

of a state-of-the-art turbocharged downsized direct injection engine, an 8-speed dualclutch transmission, and vehicle load reductions, CO2 reduction of 48-51% is achieved. 

These non-hybrid powertrain efficiency improvements, as depicted in the figure, achieve 

even lower CO2 emissions than existing hybrid models (e.g., Ford Escape and Lexus 

RX450h) that are currently the low-CO2 leading technologies within the US light-duty 

truck fleet. With diesel technology, the Ricardo results showed a potential for a 55% 

CO2 reduction from the 2007 reference. With hybridization, the Ricardo results for this 

multi-purpose vehicle class indicate the potential for a 59% CO2 reduction.
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Figure III-A-4-2. Ricardo (2011) small light-duty truck results versus existing models

Note: Figure does not include non-CO2 GHG emissions

As for the above result for a standard car and multi-purpose vehicle, the Ricardo results 

similarly showed high potential for very low CO2 emissions within full-size light-duty 

trucks. Figure III-A-4-3 shows the reference 2007 Ford F150, two leading 2011 models, 

and the Ricardo results for new powertrain and hybrid technology packages. From the 

reference 2007 Ford F150, the application of cool EGR, turbocharged, downsizing direct 

injection engine, an 8-speed dual-clutch transmission, and vehicle load reductions 

results in CO2 reduction of 46%. The GDI technology packages surpassed even the 

existing low-CO2 full-size truck (the Chevrolet Tahoe two-mode hybrid system). With 

diesel technology, the Ricardo results showed a potential for a 52% CO2 reduction from 

the 2007 reference. With hybridization, the Ricardo results for this large truck class 

indicated the potential for a 55% CO2 reduction.
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Figure III-A-4-3. Ricardo (2011) full-size truck results versus existing models

Note: Figure does not include non-CO2 GHG emissions

In order to base the technology assessment across each vehicle model across the 

entire new US vehicle fleet, the Ricardo results were utilized to further develop the 

USEPA Lumped Parameter Model in order to accurately account for the impact of each 

technology, independently as well as synergistically with other technologies across a 

greater variety of vehicle types across the entire new vehicle fleet. Table III-A-4-8

illustrates the levels of CO2 improvement that result from a selection of various 

technologies. The results show the extent to which the technologies vary, in some 

cases, from smaller car classes to larger trucks. 
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Table III-A-4-8. CO2 reduction from individual technologies from 2008 reference

Area Technology Small 

car

Mid-size 

car

Small 

light-duty

truck

Large 

light-duty

truck

Engine Engine friction reduction 3.5% 4.5% 3.4% 4.2%

technologies Cylinder deactivation - 6.1% 4.7% 5.7%

Discrete cam phasing (DCP) 4.1% 5.2% 4.1% 4.9%

Discrete variable valve lift (DVVL) 4.1% 5.2% 4.0% 4.9%

sGDI (18-bar, 33% downsize) 12.2% 14.2% 12.1% 13.6%

sGDI+DCP+DVVL (18-bar, 33% TDS) 14.9% 17.5% 14.8% 16.8%

cEGR sGDI+DCP+DVVL (27-bar, 56% TDS) 21.4% 24.3% 21.2% 23.5%

Compression-ignition DCP diesel 19.8% 21.3% 19.1% 21.3%

Transmission Torque convertor lock-up 0.4% 0.5% 0.5% 0.5%

technologies Aggressive shift logic 2.0% 2.5% 1.9% 2.4%

High efficiency gearbox 3.3% 3.9% 3.8% 4.3%

Optimized shifting 5.2% 6.6% 5.1% 6.2%

6-speed automatic 1.8% 2.2% 1.7% 2.1%

8-speed automatic 6.5% 7.8% 6.8% 7.8%

Wet dual clutch 8-speed 9.7% 11.5% 10.5% 11.9%

Dry dual clutch 8-speed 10.3% 12.2% 11.1% 12.6%

Continuously variable 11.0% 6.3% 6.0% -

Vehicle load Low drag brakes 0.8% 0.8% 0.8% 0.8%

and accessory Secondary axle disconnect 1.2% 1.4% 1.4% 1.6%

technologies Electric power steering 1.5% 1.3% 1.2% 0.8%

Improved accessory efficiency 3.3% 3.0% 2.6% 3.5%

Mass reduction (-10% curb mass) 5.1% 5.1% 5.1% 5.1%

Mass reduction (-20% curb mass) 10.4% 10.4% 10.4% 10.4%

Tire low rolling resistance (-10% Crr) 1.9% 1.9% 1.9% 1.9%

Tire low rolling resistance (-20% Crr) 3.9% 3.9% 3.9% 3.9%

Aerodynamics (-10% CdA) 2.3% 2.3% 2.3% 2.3%

Aerodynamics (-20% CdA) 4.7% 4.7% 4.7% 4.7%

Hybrid system 12V stop-start 6.1% 6.8% 5.6% 6.5%

technologies High-voltage belt-alternator system 7.4% 7.6% 6.8% 8.0%

Parallel hybrid (23-40 kW) 34.3% 34.6% 32.8% 31.9%

Reference Test weight (lb) 2625 3625 4000 6000

vehicle Rated power (hp) 106 158 169 300

characteristics Rated torque (ft-lb) 103 161 161 365

Notes: All potential CO2 improvements are from 2008 US baseline technology based on the combined US test procedure (55% 

UDDS, 45% highway); sGDI= stoichiometric gasoline direct injection; DCP=dual cam phasing; DVVL=discrete variable valve 

lift; TDS = turbocharged downsize; cEGR= cooled exhaust gas recirculation; DCT = dual clutch transmission

The technologies and their associated percent CO2 improvements shown above are 

generally not simply additive. Generally combining any two technologies listed tends to 

be less than the simple sum of the two CO2 potential values because of the ways that 

the two technologies can both impact the same fundamental physical energy efficiency 

losses through the various vehicle systems (e.g., valvetrain, fuel injection, 

thermodynamic engine efficiency, transmission, etc). Directly built upon the Ricardo 

vehicle simulation modeling results, the USEPA Lumped Parameter model incorporates 

technologies’ system interaction effects when technologies are jointly implemented. 

The analysis involved from the Ricardo results to the Lumped Parameter modeling is 

described in detail in the federal agencies’ Technical Support Document (USEPA and 

NHTSA, 2011c). 

EPA’s modeling involved the analysis of many dozens of technologies configured into 

technology packages across each of the different vehicle classes. The modeling 

resulted in varying complexity that ranged from the reference 2008 baseline technology, 

to many incremental engine and transmission package steps, to advanced hybrids and 
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electric-drive technologies. The technology package “walk-up” of technologies was 

separately analyzed for each of the 19 USEPA vehicle classifications that range from 

subcompact cars to large full-size trucks. 

Figure III-A-4-4 shows a representative progression of powertrain efficiency technology 

for the mid-size car (USEPA’s vehicle class #5). The vehicle class includes mainstream 

mid-size cars like the Toyota Camry, Ford Fusion, and Honda Accord and has a 3.3-liter 

V6 baseline engine. This is the one of 19 USEPA vehicle classes that most closely 

relates to the average US fleet characteristics (average gram CO2/mile, curb weight, 

vehicle footprint size, etc). This vehicle class has an average 2008 CO2 emission level 

of 336 gram CO2/mile (compared to the California 2008 baseline of 336 gCO2/mile and 

the US 2008 fleet’s 339 gCO2/mile). Moving down in the figure shows the incremental 

addition of more efficiency technology from the baseline. The first step involves a 

cluster of technologies that includes a 6-speed dual clutch transmission, engine friction 

reduction, low-drag brakes, aggressive shift logic, improved accessory efficiency, highefficiency gearbox, 10% reduced aerodynamic drag, 10% reduced tire rolling resistance, 

5% mass reduction, and an improved air conditioning system. This first step, referred to 

as the primary package, is included on all the gasoline efficiency technology packages 

that are to the right of it in the figure. 

Figure III-A-4-4. Technology packages for GHG emission reduction from mid-size car 

(each successive package moving right includes applicable previous technologies)
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Adding incrementally to the primary technology package, the CO2 reductions are shown 

with the addition of increasingly advanced technology. The addition of an 8-speed dual 

clutch (from a 6-speed), downsized turbocharging with an 18-bar BMEP engine, lower 

rolling resistance tires, and lower aerodynamic drag results in a package that delivers a 

CO2 emission level of 188 gCO2e/mile that is beneath the approximate 2021 target of 

201 gCO2e/mile. Subsequent GHG reduction steps of air conditioning improvements 

(for maximum potential 18.8 gCO2e/mi car credit) achieved 169 gCO2e/mile, and the 

use of cooled exhaust gas recirculation or a diesel engine would bring the midsize 

sedan’s emission level down to 156 gCO2e/mile, which is below the 2025 overall target 

emission level of 166 gCO2e/mile. Further CO2 reductions beyond the 2025 target 

levels – useful both for offsetting higher GHG vehicles and for potentially more stringent 

standards after 2025 – include greater amounts of mass reduction, hybrid, plug-in 

hybrid electric, electric, and fuel cell technology. Future California GHG intensity for 

electricity and hydrogen are assumed for electric and fuel cell vehicles, as described in

section III.A.5.3.

The full data tables with the CO2 reduction potential from the various technology 

packages for each of the 19 vehicle classes are shown in Appendix Q.

4.3. Incremental Costs of Technologies

Following the technical vehicle simulation modeling efforts, extensive new technical 

work was conducted by the agencies to analyze the incremental costs of the CO2-

reduction technologies. This regulatory development work utilizes and builds upon the 

previous work from the technical analysis of the 2012-2016 USEPA and NHTSA 

rulemaking (USEPA and NHTSA 2009a; 2009b), the joint agency TAR assessment 

(USEPA, NHTSA, CARB, 2010), and the development toward proposed federal 2017-

2025 standards (USEPA and NHTSA, 2011b; 2011c). 

In past rulemaking developments, generally there has been reliance upon cost 

estimations from confidential business information from automakers, suppliers, and 

various other automotive industry estimations. As described by the National Academy 

of Sciences (2010), “Available cost estimates are based on a variety of sources: 

component cost estimates obtained from suppliers, discussions with experts at 

automobile manufacturers and suppliers, publicly available transaction prices, and 

comparisons of the prices of similar vehicles with and without a particular technology... 

Estimates based on the more rigorous method of teardown analysis would increase 

confidence in the accuracy of the costs of reducing fuel consumption.” The agencies 

have followed this guidance and sought to support their cost estimation with best 

available technical cost data, including teardown analysis of the major CO2-reduction 

technologies.

As part of the federal 2012-2016 rulemaking and in continuing efforts since then in the 

joint-agency-TAR work, use of the comprehensive teardown cost method has been 

demonstrated. In a series of studies done under contract for the USEPA, FEV 

Engineering, Inc. has conducted detailed and transparent analyses on the costs of 
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variable valve engine technologies, turbocharged downsized engines with direct 

injection, 6-speed transmissions, dual clutch transmissions, belt-alternator system mild 

hybrids, power-split and parallel hybrid (including motors, braking, air conditioning, 

batteries, power electronics, etc). These data from the various analyses include 

detailed breakdowns of all the components and materials from each of the technologies 

and provides strong technical data support for the technology cost estimations for this 

rulemaking. These FEV data (see FEV 2009, 2010, 2011) were utilized along with the 

agencies’ direct input from suppliers and automakers to estimate the direct 

manufacturing cost of the applicable technologies. Through various communications 

with automakers, ARB staff has received strong validation of the technology cost data 

used in this analysis across the various powertrain technologies.

To incorporate how the regulation could have cost impacts that go beyond the increase 

in direct costs from the manufacture of new automotive technologies, indirect cost 

multipliers (ICMs) are utilized. The ICM framework was originally developed by a 

contractor for USEPA (Rogozhin et al, 2009; 2010) in order to delineate the relative 

impacts of the various indirect cost components (e.g., overhead, warranty, R&D, 

depreciation, corporate overhead, marketing, dealer profit). The resulting ICMs reflect 

changes with the introduction of new technology from the regulation in the short-term 

and long-term based on complexity of the technology integration on the vehicle. The 

framework had been further developed for the 2012-2016 rulemaking and the jointagency TAR, and has been further refined for this regulatory analysis (also see USEPA 

and NHTSA, 2011c). 

The ICMs used in this analysis are summarized in Table III-A-4-9. The ICMs are 

multiplied by the direct manufacturing cost to approximate the full incremental price 

increase from the regulation. As shown, the ICMs increase with technology complexity, 

but decrease when going from short- to long-term. Most incremental engine, 

transmission, and vehicle technologies are in the “Low” and “Medium” categories, and 

therefore are marked up 24-39% in the shorter term and 19-29% in the longer term. 

More advanced technologies (e.g., mass-reduction greater than 20%, hybrid, and 

electric) have larger ICM factors of 1.50 and above. This ICM framework was 

analytically developed based on incremental gasoline efficiency technology, and ARB 

staff continues to study the appropriate ICM values for advanced electric-drive vehicles 

to be used in the future. For example, a report by the National Research Council 

indicates that HEVs and plug-in hybrid electric vehicle technologies should only apply 

mark-up factors of 1.33 (NRC, 2011), and battery electric vehicles tend to have less 

integration complexity than HEVs and plug-in hybrid electric vehicles and could likewise 

be well below our conservatively assumptions.
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Table III-A-4-9. Summary of indirect cost multipliers utilized in assessment

Complexity Indirect cost multiplieraApplicable technologies Short-term Long-term

Low 1.24 1.19

Low rolling resistance tires, variable valve timing, engine friction reduction, 

low-friction lubrication, downsize, 6-speed, aggressive shift logic, torque 

convertor lock-up, improved accessory efficiency, electronic power 

steering, electro-hydraulic power steering, low-drag brakes, aerodynamics 

(10%), mass reduction (5%, 10%)

Medium 1.39 1.29

Dual-clutch transmission (wet, dry), 8-speed transmission, continuously 

variable transmission, cylinder deactivation, dual cam phasing, discrete 

valve lift, aerodynamics (20%), 42-volt accessory, stop-start, massreduction (15%, 20%), turbocharged downsizing, gasoline direct injection, 

lean-burn gasoline, diesel (LNT, SCR), continuous cam phasing, 

continuous valve lift, cooled exhaust gas recirculation

High 1 1.56 1.35 Mass reduction (25%, 30%), hybrid (powersplit, parallel), plug-in hybrid 

(non-battery costs), electric vehicle charger, fuel cell vehicle

High 2 1.77 1.50 Plug-in hybrid battery, electric vehicle battery, electric vehicle non-battery 

a ICM factors shown are approximate; the factors involve two separate components (warranty and non-warranty); see USEPA 

and NHTSA, 2011c

The resulting incremental price increase, including the direct manufacturing cost plus 

the indirect cost mark-up, for individual technologies are shown in Table III-A-4-10. As 

shown, many of the technology costs scale differently from the smaller vehicle car 

classes to the larger light-duty truck classes. Also, generally the higher cost 

technologies listed in the table are associated with larger potential CO2 reductions, as 

illustrated in the summary table above. These summary costs for individual 

technologies are used in sections below, where the technologies are built up into many 

different packages for each of the vehicle classes.
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Table III-A-4-10. Incremental vehicle price increase in year 2012 for CO2-reduction 

technologies

Area Technology Small 

car

Mid-size 

car

Small 

light-duty

truck

Large 

light-duty

truck

Engine friction reduction 124 182 182 240

Engine Cylinder deactivation - 214 214 241

technologies Discrete cam phasing (DCP) 104 104 224 224

Discrete variable valve lift (DVVL) 178 259 259 369

sGDI (18-bar, 33% downsize) 305 305 305 459

sGDI+DCP+DVVL (18-bar, 33% TDS) 578 578 578 974

cEGR+sGDI+DCP+DVVL (27-bar, 56% TDS) 1445 1445 1445 2435

Compression-ignition diesel (with aftertreatment) 3261 3994 3268 4569

Torque convertor lock-up 33 33 33 33

Aggressive shift logic 36 36 36 36

High efficiency gearbox 282 282 282 282

Transmission Optimized shifting 38 38 38 38

technologies 6-speed automatic -11 -11 -11 -11

8-speed automatic 77 77 77 77

Wet dual clutch 8-speed 52 52 52 52

Dry dual clutch 8-speed -20 -20 -20 -20

Continuously variable 243 284 284 -

Low drag brakes 73 73 73 73

Secondary axle disconnect 0 0 0 108

Electric power steering 121 121 121 121

Vehicle load Improved accessories 158 158 158 158

and accessory Mass reduction (-10% curb mass) 94 109 125 171

technologies Mass reduction (-20% curb mass) 417 482 552 756

Tire low rolling resistance (-10% Crr) 7 7 7 7

Tire low rolling resistance (-20% Crr) 72 72 72 72

Aerodynamics (-10% CdA) 54 54 54 54

Aerodynamics (-20% CdA) 234 234 234 234

Hybrid system 12V stop-start 573 650 650 713

technologies High-voltage belt-alternator 2358 2497 2497 2774

Parallel hybrid (23-40 kW electric motor size) 4408 4997 4824 5174

Reference Test weight (lb) 2625 3625 4000 6000

vehicle Rated power (hp) 106 158 169 300

characteristics Rated torque (ft-lb) 103 161 161 365

Notes: All potential incremental prices are in 2009 dollars and are from 2008 US baseline technology and include indirect cost 

multipliers for warranty, overhead, research and development, profit, etc; prices are for year 2012, and therefore time- and 

volume-based learning reduced incremental prices from 2012 through 2025 are not included; sGDI= stoichiometric gasoline direct 

injection; DCP=dual cam phasing; DVVL=discrete variable valve lift; cEGR= cooled exhaust gas recirculation; DCT = dual clutch

transmission; in ultimate technology packages, all technologies are considered along with other technologies in the table

Because some of the technologies that were considered in the rulemaking also went 

beyond the engine, transmission, and hybrid technologies to examine the future state of 

emerging electric plug-in vehicles, further data beyond that from teardown analytical 

work were required. To model the future costs of advanced battery packs for plug-in 

hybrid and full electric vehicles, battery cost estimates relied on modeling from US 

Department of Energy Argonne National Laboratory (Santini et al, 2010; Nelson et al, 

2011). Because the emerging battery technologies have different power and energy 

characteristics, the agencies utilized the Argonne battery model to analyze the specific 

technical characteristics of the hybrid, plug-in, and electric vehicles across the various 

vehicle classes. The agencies applied the Argonne model estimates for battery packs 

with lithium manganese spinel cathodes and graphite anodes. Per peer-reviewer 

feedback on the ANL cost modeling and further agency consideration with feedback 

from industry suppliers, additional active thermal management and safety disconnect 

equipment were added, thereby increasing the plug-in hybrid electric vehicle and battery 
Page 119

electric vehicle battery pack costs from the TAR generally by roughly 40-70%. 

Commonly battery costs are reported as the cost per rated kilowatt-hour (kWh) of 

energy storage capacity. For this assessment, the battery pack direct manufacturing 

costs are estimated to be $200-250/kWh for battery electric vehicles, $300-400/kWh for 

plug-in hybrid electric vehicles and $550-700/kWh for HEVs in 2025. In addition, 

external residential electricity charging equipment was included in the final cost for plugin hybrid electric vehicle and battery electric vehicle technology.

Although the available GHG credit provisions for improvements in air conditioning 

systems are optional, it is expected that they will be widely utilized by the automakers 

for compliance with the 2017-2025 standards. Table III-A-4-11 summarizes the 

estimations of technology costs associated with the available air conditioning system 

crediting mechanisms. Staff projects that the major compliance path will be to deploy 

air conditioning system efficiency technologies for maximum “indirect” credit, plus lowleak technology and substitution of the alternative refrigerant (i.e., HFO-1234yf) at a 

total marked-up price of $132 per vehicle in 2025, for an average total air conditioning 

credit of 21 gCO2/mile (18.8 for cars and 24.4 for trucks). The crediting system is a 

flexibility mechanism, and therefore automakers could choose different approaches, 

perhaps using less of any of the three air conditioning crediting provisions. 

Table III-A-4-11. GHG credits for air conditioning systems and incremental price

CO2 credit (gCO2e/mile) Incremental technology 

price ($/vehicle)

Car Truck LDV a In 2016 In 2025

Air conditioning efficiency 5.0 7.2 5.9 $61 $50

Low-leak improvements 6.3 7.8 6.9 $20 $17

Alternative refrigerant 13.8 17.2 15.1 $101 $65

Projected deployment b

(AC effic. + low-leak + alternative refrig.) 18.8 24.4 21.0 $132

a Light-duty vehicle average based on projected 61% car, 39% truck mix in 2025 b Low-leak and alternative refrigerant credits are not directly additive (see Appendix R)

Cost learning effects for all technologies are incorporated in order to consider the 

trajectory of costs for future years. The assessment utilizes both volume- and timebased learning effects. The volume-based learning is included only for relatively new

technologies in earlier years, whereas time-based learning is generally considered at 

3%/year cost reductions (newer technologies) down to 1%/year (mature technologies in 

the longer-term). These assumptions for learning are consistent with assumptions 

applied in the US EPA 2012-2016 rulemaking (US EPA and NHTSA, 2010) and the 

joint-agency TAR (USEPA, NHTSA, CARB, 2010).

The analysis on technology package CO2 potential, technology costs, and indirect cost 

mark-up factors are brought together in incremental price - CO2 data files for each of 

the 19 vehicle technologies. These vehicle price versus CO2 reductions become the 

basis for analyzing the maximum technology capability for given levels of cost for each 

vehicle class, and therefore these serve as the critical inputs to analyze standard 
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stringency levels and potential compliance scenarios for the fleet as a whole for each of 

the affected automakers.

Figure III-A-4-5 shows a representative walk-up in price with incremental additions in 

CO2 reduction technology for a mid-size sedan (vehicle class 5 out of 19). The data in 

the figure show the progression from the lowest cost technologies to more advanced 

technologies with higher costs. The first package of technologies includes engine 

friction reduction, a 6-speed dual-clutch transmission, low-drag brakes, aggressive shift 

logic, improved accessories, electric power steering, high-efficiency gearbox, reduced 

vehicle loads (10% lower aerodynamic drag, 10% lower tire rolling resistance, and 5% 

mass reduction). From the primary package, moving up and to the right in the figure 

shows the addition of 8-speed transmission, downsized turbocharged GDI engine, 

further load reduction, air conditioning technologies, and more advanced technologies. 

Note that hybrid, plug-in hybrid, electric, and fuel cell technologies have higher costs 

and higher potential CO2 reduction and are not represented in the chart (although they 

are shown in Figure III-4-A-4-7 below).

Figure III-A-4-5. Vehicle CO2 reduction and incremental price with additional 

technologies from 2008 baseline for mid-size car (Vehicle class 5 out of 19)

Figure III-A-4-6 shows the increasing price with incremental additions in CO2 reduction 

technology for a large truck with a baseline 5.7-liter V8 engine with overhead valves and 

4-speed transmission (vehicle class 13 out of 19). Many of the engine, transmission, 

and vehicle load technologies are similar to the above car. However, there are a 

number of differences for this truck class from the car class above. For example, the 

truck utilizes an 8-speed automatic instead of dual-clutch transmission, would receive 

greater air conditioning credit, and deploys more GHG reduction technologies before 

switching to a turbocharged, downsized engine. Note that hybrid technology for this 

package is greater than $5000 and is similarly not represented in the chart. The 

agencies have studied plug-in hybrid and full electric vehicle technologies for larger 
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body-on-frame truck classes but did not include these technologies in the final analysis 

for these larger trucks due to uncertainties about total cost and full utility functioning 

(electric drive technologies were however included in crossover truck classes). The full 

lists of technology packages, vehicle price, and CO2 potential for the 19 vehicle classes 

are shown in Appendix Q.

Figure III-A-4-6. Vehicle CO2 reduction and incremental price with additional 

technologies from 2008 baseline for full-size truck (Vehicle class 13 out of 19)

The two above technology figures for the mid-size car and a full-size truck focused on 

incremental engine, transmission, and vehicle technologies that are the most prominent 

near-term technologies for complying with 2017-2025 standards. To show a more full 

spread of the advanced technologies, the following Figure III-A-4-7 illustrates the 

technology, CO2-reduction, and incremental price for two smaller car classes (USEPA 

classes 1, 2, and 4) that are more likely to see hybrid, electric, and fuel cell deployment 

in the 2025 timeframe. The figure shows similar incremental technologies to those 

above, but it also shows parallel hybrid technology at about $4,000, plug-in hybrid 

technology at about $9,000-$14,000, fuel cell technology at $8,000-$11,000, and full 

battery electric technology at about $10,000-$15,000 over the baseline 2008 vehicle. 

Note that, in this figure, plug-in vehicles are shown according to their projected future 

California electricity GHG emissions for the extent to which they are powered by grid 

electricity. Similarly, the fuel cell vehicles are shown according to their projected 

upstream GHG emission rate (e.g. including emissions from hydrogen production from 

natural gas and renewable sources) per existing and proposed California fuel policy, as 

described in greater detail below.
Page 122

Figure III-A-4-7. Vehicle CO2 reduction and incremental price with additional 

technologies from 2008 baseline for small to mid-size cars

The results of the joint agency assessment indicated that hybrid technology and 

electric-drive technologies would continue to remain at high costs for some time. ARB 

staff believes ultimately that these projected advanced technology costs are 

conservative (i.e., actual costs may be lower), as they are limited by our current 

understanding of a number of immature in-development technologies that are rapidly 

evolving compared to the incremental efficiency technologies. As one potential 

indicator of the inherent conservatism of these estimates, there are many hybrid and 

diesel vehicles in the market with incremental prices (versus their comparable 

conventional gasoline versions) that are considerably less than the incremental prices 

applied in this assessment of 2020-2025 technologies. In addition, ARB staff continues 

to investigate the ways in which electric vehicles could have much lower indirect cost 

multipliers than conventional supplier-sourced gasoline efficiency components. 

Conservatively, electric-vehicle components are estimated here to have indirect cost 

multipliers of 1.50 to 1.77, whereas the National Research Council (NRC) suggests that 

a more accurate indirect multiplier for such battery-heavy technologies could be more 

like 1.33 (NRC, 2011). Due to the relatively small current numbers of these relatively 

new technologies, staff believes that these conservative assumptions are justified at this 

time.

4.4. Lifetime Cost of Technologies to Vehicle Owner-Operator

As part of the technology cost assessment, all of the technology packages have been 

examined with respect to their lifetime impact on vehicle owners. Table III-A-4-12

summarizes details for 2025 incremental price, consumer lifetime savings, benefit/cost 

ratio, and consumer payback period for technology packages for the mid-size car with a 

V6 engine (USEPA class #5). This vehicle class is shown here to provide a 
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representative summary of vehicle class in the middle of the fleet (by footprint size, 

engine size, and CO2 emissions). As shown in Table III-A-4-12, there are 12 different 

technology packages that result in somewhere between 30% and 52% CO2 reduction 

from the 2008 baseline, that deliver consumer benefits that are least 5 times higher than 

the original vehicle cost, and that pay for themselves within the first two years of the 

consumer’s purchase (i.e., payback period). To highlight an example from the table, the 

technology package that includes turbocharged, downsized gasoline direct injection 

engine, 8-speed dual-clutch transmission, and vehicle load reduction technologies 

(improvements of 20% aerodynamic drag, 20% low rolling resistance tires, 10% mass 

reduction); results in 44% lower CO2 emissions; has an increased 2025 price to 

consumers of $1,431 (from 2008); returns lifetime consumer savings of $11,761; offers 

8.2 times greater benefits than costs; and delivers a payback period in the first year.
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Table III-A-4-12. Summary sample technology package effectiveness, price, lifetime 

savings, payback period for mid-size vehicle versus 2008 baseline technology

Technology package

GHG 

reduction 

from 

baseline

Increm

ental 

price in 

2012

Increm

ental 

price in 

2020

Increm

ental 

price in 

2025

Lifetime 

consumer 

fuel 

savings

Benefit/ 

cost

Consumer 

payback 

period 

(years)

Base: 3.3L 4V DOHC V6, 4sp AT 0.0% $0 $0 $0 $0 - 0

4V DOHC V6, EFR2, LDB, ASL2, IACC, EPS, Aero1, LRRT1, 

HEG, 6sp DCT, 5% mass 27.3% $782 $676 $627 $7,263 11.6 1

4V DOHC I4, EFR2, LDB, ASL2, IACC, EPS, Aero1, LRRT1, 

HEG, DCP, GDI, TDS18, 6sp DCT, 5% mass 37.4% $1,365 $1,101 $1,039 $9,953 9.6 1

4V DOHC I4, EFR2, LDB, ASL2, IACC, EPS, Aero1, LRRT1, 

HEG, DCP, GDI, TDS18, 8sp DCT, 5% mass 39.4% $1,519 $1,234 $1,153 $10,479 9.1 1

4V DOHC I4, EFR2, LDB, ASL2, IACC2, EPS, Aero2, LRRT2, 

HEG, DCP, GDI, TDS18, 8sp DCT, 5% mass 42.6% $1,825 $1,491 $1,367 $11,341 8.3 1

4V DOHC I4, EFR2, LDB, ASL2, IACC2, EPS, Aero2, LRRT2, 

HEG, DCP, GDI, TDS18, 8sp DCT, 10% mass 44.2% $1,915 $1,562 $1,431 $11,761 8.2 1

4V DOHC I4, EFR2, LDB, ASL2, IACC2, EPS, Aero2, LRRT2, 

HEG, DCP, GDI, TDS18, 8sp DCT, 15% mass 45.8% $2,094 $1,717 $1,556 $12,187 7.8 1

4V DOHC I4, EFR2, LDB, ASL2, IACC2, EPS, Aero2, LRRT2, 

HEG, DCP, GDI, SAX, TDS18, 8sp DCT, 15% mass 46.1% $2,202 $1,804 $1,636 $12,277 7.5 1

4V DOHC I4, EFR2, LDB, ASL2, IACC2, EPS, Aero2, LRRT2, 

HEG, DCP, DVVL, GDI, SAX, TDS18, 8sp DCT, 15% mass 46.6% $2,381 $1,946 $1,767 $12,393 7.0 2

4V DOHC I4, EFR2, LDB, ASL2, IACC2, EPS, Aero2, LRRT2, 

HEG, DCP, GDI, TDS24, EGR, 8sp DCT, 10% mass 48.0% $2,540 $2,140 $1,891 $12,770 6.8 2

4V DOHC I4, EFR2, LDB, ASL2, IACC2, EPS, Aero2, LRRT2, 

HEG, DCP, GDI, TDS24, EGR, 8sp DCT, 15% mass 49.5% $2,719 $2,295 $2,015 $13,166 6.5 2

4V DOHC I4, EFR2, LDB, ASL2, IACC2, EPS, Aero2, LRRT2, 

HEG, DCP, GDI, SAX, TDS24, EGR, 8sp DCT, 15% mass 49.8% $2,827 $2,382 $2,096 $13,250 6.3 2

4V DOHC I4, EFR2, LDB, ASL2, IACC2, EPS, Aero2, LRRT2, 

HEG, DCP, GDI, SS, SAX, TDS24, EGR, 8sp DCT, 15% mass 50.3% $3,477 $2,768 $2,439 $13,383 5.5 2

4V DOHC I4, EFR2, LDB, ASL2, IACC2, EPS, Aero2, LRRT2,

HEG, DCP, GDI, SS, SAX, TDS27, EGR, 8sp DCT, 15% mass 50.8% $4,055 $3,266 $2,863 $13,510 4.7 2

4V DOHC V6, EFR2, LDB, ASL2, IACC2, EPS, Aero2, LRRT2, 

HEG, DCP, DVVL, GDI, ATKCS, HEV, 8sp DCT, 20% mass 59.3% $7,519 $5,702 $5,024 $15,773 3.1 3

4V DOHC V6, EFR2, LDB, ASL2, IACC2, EPS, Aero2, LRRT2, 

HEG, DCP, DVVL, GDI, ATKCS, HEV, SAX, 8sp DCT, 20% mass 59.6% $7,627 $5,790 $5,104 $15,848 3.1 3

4V DOHC I4, EFR2, LDB, ASL2, IACC2, EPS, Aero2, LRRT2, 

HEG, DCP, DSL-Adv, SAX, 8sp DCT, 15% mass 47.8% $5,659 $4,573 $4,181 $12,731 3.0 3

EV75 mile, IACC2, Aero2, LRRT2, EPS, 20% mass 91.7% $29,835 $16,554 $12,579 $19,304 1.5 7

EV100 mile, IACC2, Aero2, LRRT2, EPS, 20% mass 91.7% $34,198 $18,903 $14,314 $19,304 1.3 9

4V DOHC V6, EFR2, LDB, ASL2, IACC2, EPS, Aero2, LRRT2, 

HEG, DCP, DVVL, GDI, ATKCS, REEV20, 8sp DCT, 20% mass 71.8% $22,671 $14,433 $12,156 $17,068 1.4 8

4V DOHC V6, EFR2, LDB, ASL2, IACC2, EPS, Aero2, LRRT2, 

HEG, DCP, DVVL, GDI, ATKCS, REEV40, 8sp DCT, 20% mass 79.3% $30,922 $18,714 $15,341 $17,894 1.2 11

EV150 mile, IACC2, Aero2, LRRT2, EPS, 20% mass 91.7% $48,556 $26,545 $19,951 $19,304 1.0 16

FCV, IACC2, Aero2, LRRT2, EPS, 10% mass 78.2% $64,885 $18,282 $14,357 $14,029 1.0 16

Notes: Assumptions for lifetime consumer savings, benefit/cost ratio, and payback period include median vehicle lifetime for cars 

of 14 years, 186,000 miles; fuel prices from California Energy Commission (e.g., $4.02/gallon gasoline in 2025); 5% discount rate; 

on-road consumer fuel consumption per mile is 25% greater than regulatory test-cycle values; air conditioning credits that would 

be worth about 18.8 gCO2e/mile at about $132/vehicle are not shown; $0.15/kWh for electric vehicles; $6 per kilogram hydrogen 

for fuel cell vehicle; 2020 California primary energy sources are assumed for electric and fuel cell vehicles.
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Although the full summary of technology packages for the 19 vehicle classes is shown 

in Appendix Q, an illustrative selection of CO2-reduction packages that corresponds 

approximately with the proposed standard stringency levels is shown in Table III-A-4-13. 

The table x shows example technology packages that deliver an approximately 50% 

CO2e emission reduction from a 2008 reference technology for four different vehicle 

classes. Technology comparisons against a projected 2016 fleet are made below when 

compliance scenarios are analyzed. Across the four classes the technology package 

that is shown is quite similar. All involve turbocharged, gasoline direct injection, 8-

speed transmissions, load reduction technologies (from 10-20% reductions in mass, 

aerodynamics, and tire rolling resistance), improved accessory efficiency, and low-CO2e 

air conditioning technologies. Each of the listed technologies achieves benefits in 

consumer savings that are between 4.7 and 7.4 times greater than the initial price 

increase for the technology, and the consumer payback period of each package is 

within 2 years.

Table III-A-4-13. Example of technology packages for 50% GHG-reduction for four 

different vehicle classes

Small car Mid-size car Midsize truck Large truck

USEPA class 2 5 8 13

Baseline engine Base: 2.4L 4V 

DOHC I4

Base: 3.3L 4V 

DOHC V6

3.7L 2V SOHC 

V6 5.7L 2V OHV V8

Baseline 

2008

Test cycle CO2

(gCO2/mi) 238 336 390 448

technology

Example models

Honda Civic; 

Chev Malibu; 

Hyundai Elantra

Honda Accord; 

Toyota Camry; 

Ford Fusion

Ford Ranger; 

Jeep Liberty

Chev Tahoe; Chev 

Silverado

Technology 

package

4V DOHC I4, EFR2, 

LDB, ASL2, IACC2, 

EPS, Aero2, LRRT2, 

HEG, DCP, GDI, 

TDS18, 8sp DCT, 

2% mass

4V DOHC I4, EFR2, 

LDB, ASL2, IACC2, 

EPS, Aero2, LRRT2, 

HEG, DCP, GDI, 

TDS18, 8sp DCT, 

10% mass

4V DOHC I4, EFR2, 

LDB, ASL2, IACC2, 

EPS, Aero2, LRRT2, 

HEG, DCP, GDI, 

TDS24, EGR, 8sp 

DCT, 10% mass

4V DOHC I4, EFR2, 

LDB, ASL2, IACC2, 

EHPS, Aero2, LRRT2, 

HEG, DCP, GDI, SAX, 

TDS27, EGR, 8sp AT, 

10% mass

Test cycle CO2

(gCO2/mi) 139 188 217 242

Test cycle CO2

reduction from 2008 42% 44% 44% 46%

Example of 

technology

Air conditioning 

credit (gCO2e/mi) 18.8 18.8 24.4 24.4

for 2025 Regulatory GHG 

(gCO2e/mi) 120 169 192 218

GHG reduction after 

A/C credit 50% 50% 51% 51%

Incremental price 

versus 2008 ($) 1,645 1,563 2,103 2,730

Lifetime savingsb

versus 2008 ($) 7,871 11,761 15,320 18,256

Benefit/cost b 4.8 7.5 7.3 6.7

Consumer payback 

period (years) b 2 1 2 2

a A 2008 technology baseline is used for vehicle simulation modeling, cost estimations; further below, in compliance 

assessment, future scenarios are compared against a model year 2016 baseline that is more appropriate as a “no new 

policy” reference that includes standards through 2016. b Consumer impacts based on 5% discount rate, fuel prices from 2011 CEC forecast (e.g., $4.09/gallon gasoline in 2025), 

California median vehicle lifetime (186,000, 14 years for car; 234,000 17 years), real world on-road fuel efficiency is lower 

than that calculated for CAFE.
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4.5. Summary

This section III.A.4 reported on Staff’s investigation into available CO2-reduction 

technologies, their associated incremental prices and potential fuel savings to 

consumers. The findings from this assessment reveal that there are wide-ranging 

technology options available to automakers to reduce the CO2 emissions of vehicles in 

the 2017-2025 timeframe. Many of the technologies are already well known today and 

are beginning to emerge within new vehicle introductions. Many of the technologies are 

more advanced, involving cutting edge technology innovation by automakers. Many of 

the technologies for CO2 reduction will be combined in packages to deliver substantial 

CO2 reduction in new vehicles that amount to between 30% and 55% from 2008 

technology levels. For comparison, the 2016 standards would result in an approximate 

25% CO2 reduction from 2008 reference, so the technologies investigated would go far 

beyond the emission levels required for the 2016 standards. These levels of CO2

reduction typically represent payback periods of 1-3 years for vehicle purchasers 

because of the emerging relatively low-cost engine, transmission, and vehicle load 

technologies. Hybrid technologies typically result in 50-60% CO2 emission reduction 

from each vehicle class at higher costs. Plug-in electric and fuel cell technology will 

continue to offer the lowest CO2 emissions of all, but typically at a greater price 

premium. In nearly every case of the technology packages investigated, the benefits of 

the new technologies offer consumer benefits that outweigh their initial technology 

costs, often well within the average first vehicle purchaser’s ownership and several 

times over during the vehicle’s life.

5. CLIMATE CHANGE EMISSION STANDARDS 

The establishment of GHG standards from the technical work outlined above involved a 

collaborative process between the technical staffs of the USEPA, NHTSA, and ARB. 

The collaborative standard-setting process allowed the agencies to set standards that 

simultaneously met the agencies’ respective statutory authorities and rulemaking

procedures. 

5.1. Determination of Maximum Feasible Emission Reduction Standard

The proposed standards involve continuing use of footprint-indexed CO2-standards that 

are part of the federal 2012-2016 standards, a structure that is justified on both 

technical and regulatory consistency grounds. The technical basis for footprint-indexed 

standards is well established in the USEPA and NHTSA (2009) rulemaking (and 

NHTSA’s previous rulemakings) for its benefits in promoting all known CO2 reduction 

technologies, accommodating fluctuating consumer demands for vehicle size and 

classes, and protecting fleet diversity across the wide array of different products that 

automakers market. ARB staff finds the existing non-footprint-indexed California 2009-

2016 standards are valid on account of their more certain emission reduction outcome; 

however, for regulatory continuity with the federal 2012-2016 standards and their 

above-stated benefits, it was critical that the same footprint-indexed regulatory design 
Page 127

be applied. Because compliance with the federal 2012-2016 standards will be deemed 

as sufficient for compliance with California’s GHG standards for those model years and 

because of the federal US-California collaboration on issuing joint standards, the 

standard design with separate car and truck footprint-indexed standard lines was 

maintained.

The footprint-indexed CO2 standard target lines for 2017-2025 were determined jointly 

by the three agencies in order to meet the agencies’ regulatory requirements that 

include the agencies’ criteria regarding technical feasibility and cost-effectiveness. ARB 

staff were guided by the overarching ARB objectives from AB 1493 (Chap. 200, Stats. 

2002) remains to “develop and adopt regulations that achieve the maximum feasible 

and cost-effective reduction of greenhouse gas emissions” such that the standards are 

“Economical to an owner or operator of a vehicle, taking into account the full life-cycle 

costs of a vehicle.” In addition, AB 32 (Chap. 488, Stats. 2006) instructs staff to adopt 

measures “to achieve the maximum technologically feasible and cost-effective [GHG] 

reductions.” Among the agencies’ considerations in their analyses were the technical 

feasibility (across the various vehicle types and sizes), statutory provisions of the 

agencies (e.g., different treatment by NHTSA of air conditioning credits), company 

competitiveness, relative cost-effectiveness across vehicle sizes and types, risks of 

eroded GHG program benefits from consumer trends, risks of eroded GHG program 

benefits from strategic vehicle reclassification by vehicle manufacturers, and the 

potential market shifting effects on fleet safety.

The primary technical data that was utilized in the standard-setting process was the 

vehicle simulation modeling of technology packages that includes many of the engine, 

transmission, and vehicle technologies (as discussed in the previous section) that are 

projected to be widely available by the 2025 timeframe. The vehicle technologies that 

were applied to vehicle models in the standard-setting analysis included downsized 

turbocharged engines, gasoline direct injection, 8-speed transmissions, vehicle load 

reduction (aerodynamics and low-rolling resistance tires), improved and more efficient 

accessories, engine friction reduction, and transmission shift optimization. The 

technology packages used in the analytical development of the footprint-indexed curves 

in the standard-setting process did not include diesel, hybrid, plug-in, electric, or fuel cell 

technologies. (Note, however, that the analysis of the various companies’ strategies to 

comply with the footprint-indexed standards does consider deployment of these 

technologies. See section III.A.5.4, below).

Throughout the footprint target line-fitting analysis, many dozens of approaches were 

analyzed. Among the approaches different statistical regression methods were used to 

discern the relationship between future vehicle technologies’ CO2 and vehicle footprint. 

Also various normalization techniques were considered to adjust for particular vehicle 

attributes, such as a models’ relative power and mass, as the agencies considered 

various advanced vehicle technology packages. The general process involved starting 

from the baseline 2008 vehicle fleet, adjusting for the introduction of projected 

mainstream 2025 CO2-reduction technologies, statistically analyzing the data for the 

CO2-to-footprint (gCO2/mile/ft2

) relationships, then mathematically adjusting the curves 
Page 128

proportionally up or down depending on the targets’ overall stringency. Ultimately, the 

ordinary least squares regression method, the most widely used statistical line-fitting 

technique, was applied to best approximate the physical relationship between models’ 

CO2 and footprint. The data were weighted according to their vehicle sales, in order to 

best reflect the true consumer-demanded distribution of vehicles according to various 

sizes, technologies, and classes. Finally, vehicle models’ density (mass divided by 

footprint) was normalized in setting the footprint-indexed curves, as a means to adjust 

for relative differences in the models’ mass-efficiency. The overall logic behind these 

decisions was to discern the true engineering-based CO2-to-footprint relationship for 

2017-2025 target curves across all vehicle models by applying widely recognized 

statistical techniques to incorporate variance in the fleet.

The above steps were used to define the slopes of the curves. Further detail on the 

standard-setting development can be found in the federal agencies’ Technical Support 

Document (USEPA and NHTSA, 2011c). The movement of the slopes to set the overall 

year-by-year stringency targets for car and trucks was determined through staff analysis 

and discussions with automakers In the analysis, consideration of auto companies’ 

current and future year product plans for compliance with the 2012-2016 program 

standards, as well as the companies’ stated capability within the first several years of 

the 2017-2025 program. The final step in determining the precise stringency of the 

footprint-indexed car and truck standards was accounting for information shared 

between the regulatory agencies and the automobile manufacturers, applying the 

agencies’ historical expertise in standard-setting.

Figures III-A-5-1 and III-A-5-2 provide graphical illustrations of the proposed footprintindexed GHG standards. Also shown in the figures are the baseline model year 2008 

car and truck models. Based on staff projections for the 2025 new vehicle fleet, the car 

and truck models will need to, on a weighted average, reduce their GHG emissions by 

about 51% from 2008 levels to comply with the standards. The 2008 emission level is 

utilized here and above as a technology reference for all of the technology effectiveness 

calculations by the three agencies, because it is the most comprehensive dataset for 

which all data (e.g., sales, footprint, CO2 emissions for every model) are well 

characterized. Compliance with the already-implemented model year 2016 standards is 

expected to result in a 25% reduction from the 2008 reference CO2 level. The 2025 

GHG emission target is projected to result in a 34% reduction from the model year 2016 

GHG emission level. Generally the car CO2 standard target curves move downward –

i.e., become more stringent – at approximately 4.9%/year from the 2016 target line to 

the 2025 target line. The truck CO2 standard target curves move downward at 

approximately 3.5%/year through the 2016-2021 period and about 5%/year from 2021-

2025. These annual percent improvements are approximate, based on staff projections 

for future vehicle sales.
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Figure III-A-5-1. Model year 2017-2025 car GHG standard target lines

Figure III-A-5-2. Model year 2017-2025 light-duty truck GHG standard target lines

The actual standards for each automaker are determined by target standard lines for 

the sales-weighted average of their vehicle fleet, as defined by particular mathematical 

coefficients for car and trucks and for each model year. The standard target lines for 

model years 2017-2025 in the figures are represented by the following mathematical 

expression: 

Target gCO2/mile = min(min(b,max(a,cx+d),min(f,max(e,gx+h))))

The only unknown in the expression is x, which is the vehicle footprint (wheelbase times 

average track width), measured in ft2

. Coefficients a through h for cars and trucks for 

model years 2017-2025 are shown in Table III-A-5-1 below.
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Table III-A-5-1. Standard-determining coefficients for model year 2017-2025 car and lightduty truck GHG standards

Coefficient 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025

Cars a Min (gCO2/mile) 206 194.7 184.9 175.3 166.1 157.2 150.2 143.3 136.8 130.5

b Max (gCO2/mile) 277 262.7 250.1 238 226.2 214.9 205.5 196.5 187.8 179.5

c Slope (gCO2/mi/ft2) 4.72 4.53 4.35 4.17 4.01 3.84 3.69 3.54 3.4 3.26

d Intercept (gCO2/mi) 12.7 8.92 6.54 4.2 1.89 -0.38 -1.12 -1.83 -2.52 -3.17

e Min (gCO2/mile), ceiling 203.4 201.9 200.4 198.9 197.4 197.4 197.4 197.4 197.4

f Max (gCO2/mile), ceiling 274.4 277 278.5 280 281.5 283 283 283 283

g Slope (gCO2/mi/ft2), ceiling 4.72 4.72 4.72 4.72 4.72 4.72 4.72 4.72 4.72

h Intercept (gCO2/mi), ceiling 10.1 8.6 7.1 5.6 4.1 4.1 4.1 4.1 4.1

Trucks a Min (gCO2/mile) 247 238.1 226.8 219.5 211.9 195.4 185.7 176.4 167.6 159.1

b Max (gCO2/mile) 348 347.2 341.7 338.6 336.7 334.8 320.8 305.6 291 277.1

c Slope (gCO2/mi/ft2) 4.04 4.87 4.76 4.68 4.57 4.28 4.09 3.91 3.74 3.58

d Intercept (gCO2/mi) 81.1 38.28 31.62 27.69 24.64 19.8 17.85 15.98 14.21 12.51

e Min (gCO2/mile), ceiling 246.4 240.9 237.8 235.9 234 234 234 234 234

f Max (gCO2/mile), ceiling 347.4 341.9 338.8 336.9 335 335 335 335 335

g Slope (gCO2/mi/ft2), ceiling 4.04 4.04 4.04 4.04 4.04 4.04 4.04 4.04 4.04

h Intercept (gCO2/mi), ceiling 80.50 75.0 71.9 70 68.1 68.1 68.1 68.1 68.1

To calculate each automaker’s fleet GHG target, first the GHG target for each test 

vehicle is calculated from the above formula and coefficients. A car model uses the car 

coefficients, and trucks use the truck coefficients. The above figures illustrate the GHG 

standards that result from the calculations for each model year and for the two vehicle 

categories. For example, a car below 41 ft2 would get the minimum standard target 

(i.e., the lower, left flat part of the line), a car above 56 ft2 would get the maximum 

standard target (i.e., the higher, right flat part of the line), and the rest of the car models 

would get a GHG target based on the linear CO2-ft2 relationship between 41 and 56 ft2

, 

as defined by the formula. Calculating the truck model targets would follow the same 

logic. As shown by the target lines, each model at a given footprint gets a more 

stringent target in each successive model year.

From all of the test vehicles’ individual GHG targets, the sales-weighted average of the 

gCO2/mile standard targets for each automaker, for each model year (i.e., 2017-2025), 

determines the standard. For compliance, each automaker’s sales fleet in a given year 

is to have a sales-weighted gCO2/mile that is below their sales-weighted gCO2/mile 

target. Due to sales-weighting of the model-by-model results, a compliant fleet can 

have many particular models that are below the target line (i.e., generating credits) and 

many other models above the line (i.e., generating deficits). As a result of this process, 

the precise gCO2e emissions/mile standard for each company is not definitively known 

until the final sales for that model year is known (e.g., this can be as late as April 2012 

for model year 2011 sales). Within the 2017-2025 standards, banking (5-year credit 

carry-forward, 3-year credit carry-back to cover past deficits) and trading (between car 

and truck categories, between companies) are permitted.

5.2. Determination of Effect of Standard on the Fleet

The potential effect of the standards on the fleet, and on individual companies, is 

analyzed based on the previous section’s assessment of available technologies, their 

potential CO2-emission reduction, and the associated technology costs. The first step 
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in estimating the potential compliance costs for automakers in achieving the required 

CO2 emission reductions involves the determination for each of the automakers 

particular gCO2/mile targets for each model year of the standards based on the 

footprint-indexed standards. In other words, the GHG standard is calculated separately 

for each automaker for each model year based on the footprint size of its sales fleet. 

Then the potential compliance costs are evaluated by applying additional GHGreduction technology to bring the fleet into compliance with incrementally lower GHG 

standards in future years.

Table III-A-5-2 shows the CO2 target standards based on the California 2008 baseline

fleet, the projected 2016 CO2 targets based on federal standards, and the projected 

2025 CO2 target for each company based on their mix of cars and trucks for the 

proposed footprint-indexed standards. As summarized in the figure, the already 

adopted 2016 standards would reduce the CO2 emissions from the fleet by 25% from 

2008 to 2016 (with a range of reductions 19% to 39% for the given automakers). The 

proposed 2025 standards would reduce CO2e emissions from the fleet by 34% from 

2016 to 2025. 

Table III-A-5-2. Summary of projected GHG targets and reductions for 2016 and 2025 

standards

Company

GHG emissions (gCO2e/mile) Reduction in GHG emissions

2008 baseline 2016 target 2025 target Change from 

2008 to 2016

Change from 

2016 to 2025

BMW 335 235 151 30% 35%

Chrysler-Fiat 363 260 171 28% 34%

Ford 385 264 178 31% 33%

General Motors 372 274 184 26% 33%

Honda 296 240 157 19% 35%

Hyundai-Kia 309 238 155 23% 35%

Jaguar-Land Rover 447 274 184 39% 33%

Mazda 310 235 152 24% 35%

Mercedes 368 252 165 31% 34%

Mitsubishi 313 228 146 27% 36%

Nissan 329 248 164 25% 34%

Spyker 354 230 148 35% 36%

Subaru 341 255 169 25% 34%

Suzuki 338 237 155 30% 35%

Toyota 304 248 163 19% 34%

Volvo 377 248 163 34% 34%

Volkswagen 328 226 146 31% 35%

All 336 251 166 25% 34%

Figure III-A-5-3 shows the progression of the highest volume manufacturers’ GHG 

emission targets from 2016 through 2025 based on each company’s fleet mix by 

category and footprint. As illustrated, the footprint-indexing of the GHG standards 

ultimately results in different effective standards for each automaker depending on their 

fleet mix. The seven automakers with projected sales fleets with the smallest average 

footprint have GHG emission targets of 146-155 gCO2e/mile, whereas the four largestfootprint companies would have targets of 171-184 gCO2e/mile. Also resulting from the 
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footprint-indexing of the standards, the total obligated emission reduction, by percent, 

from each automaker is quite similar – ranging from a 33% to a 36% GHG reduction.

Figure III-A-5-3. Projected GHG emission targets for high-volume auto manufacturers 

from 2016-2025

5.3. Other Greenhouse Gas Emission Crediting Provisions

A number of provisions that account in part for driving conditions beyond the customary 

city-highway drive cycle tailpipe emission testing are provided within the proposed 

2017-2025 MY standards. The air conditioning (A/C) credit provisions that offer up to 

18.8 gCO2e/mile for cars and 24.4 gCO2e/mile for light-duty trucks were mentioned 

above in section III.A.4.4 and are described in detail in Appendix R. These A/C 

crediting provisions would be available for prescribed technologies with credit amounts 

for improved A/C efficiency (indirect credits), and lower leak refrigerant systems and 

alternative refrigerants (direct credits). The A/C credit opportunities, although optional, 

are highly cost-effective and expected to be widely utilized by automakers for 

compliance with the fleet average standards based on staff communication with 

automakers and the supplier industry companies involved in the manufacture of the 

technologies.

For the Pavley and federal 2012-2016 MY standards, ARB and USEPA, respectively, 

used differing methodologies for quantifying the GHG emissions from A/C and thus 

differing credit schemes. However, for the 2017-2025 MY standards, ARB staff is 

proposing to align with the USEPA approach as it would provide a consistent program 

nationwide as well as regulatory continuity across the federal 2012-2016 MY and 

federal 2017-2025 MY regulations that California proposes to continue accepting. The 

proposed regulation would also incentivize employment of leakage reduction 

technologies for A/C systems that use a refrigerant with a GWP of 150 or less (low 

GWP refrigerant), which would help maintain A/C performance and efficiency by 

keeping proper refrigerant charge level, and would reduce the need for and therefore 
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potential of consumers recharging low GWP refrigerant A/C systems with less 

expensive and higher GWP HFC-134a.

Table III-A-5-3 shows the maximum credit available to manufacturers for applying 

various classes of A/C technology improvements. To qualify for A/C direct credits, an 

automobile manufacturer would need to conduct an engineering evaluation that 

demonstrates that the A/C system is designed to limit refrigerant leakage. A larger 

direct credit may be earned if the manufacturer uses an alternative, low GWP, 

refrigerant. In order to qualify for indirect credits, automakers would need to 

demonstrate that their efficient A/C systems can provide CO2 reductions commensurate 

to the amount of indirect credits allowed. As described in detail in Appendix R, the A/C 

Idle Test currently in place for the 2012-2016 MY regulation does not measure the 

benefit of several efficiency technologies. In addition, vehicles with efficient, downsized 

engines have difficulty passing the test even when equipped with A/C efficiency 

technologies. Because downsized engines are likely to be used by manufacturers as a 

compliance pathway for the fleet average GHG standards, in order to maintain program 

flexibility, ARB staff is proposing to replace the A/C Idle Test requirement with a 

requirement based on a new performance-based efficiency test, the AC17. The AC17 

is true performance-based efficiency test, the AC17, which may be used as an alternate 

test option to qualify for indirect A/C credits. This true performance-based test that 

evaluates all types of efficiency technologies over “real-world” driving conditions, and as 

such, is preferred over the current A/C Idle Test, which is limited in its ability to evaluate 

A/C efficiency technologies and represents only idle conditions (estimated at 13.5% of 

driving conditions).

Table III-A-5-3. Maximum credits available to manufacturers

Refrigerant Emission 

Reduction Strategy

Max Credit 

(gCO2e/mi)

Cars Trucks

HFC-134a

Low Leak 6.3 7.8

Improved Efficiency 5.0 7.2

Total 11.3 15.0

Low GWP

Low GWP 13.8 17.2

Improved Efficiency 5.0 7.2

Total 18.8 24.4

The proposed AC17 test procedure was developed in concert with USEPA and US 

automakers, and contains the following elements: a unified dynamometer driving 

schedule (UDDS or LA92) preconditioning cycle, a period of solar soak (30 minutes), an 
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air conditioning test (SC03) drive cycle to evaluate emissions during the initial cooldown of the vehicle, and a highway fuel economy test (HFET) drive cycle to evaluate 

GHG emissions during steady state operation of the MVAC system and relatively steady 

state driving conditions. Performing these test elements under moderate temperature 

and humidity test cell conditions allows the efficiency of the whole MVAC system, 

including solar control, to be measured. For vehicle models that manufacturers are 

seeking to earn A/C efficiency credits, the AC17 test would be conducted to validate 

that the performance and efficiency of a vehicle’s A/C technology is commensurate with 

the level of credit that is being earned. To determine whether the efficiency 

improvements of these technologies are being realized, the results of an AC17 test 

performed on a new vehicle model would be compared to a “baseline” vehicle that does 

not incorporate the efficiency-improving technologies. The baseline vehicle would be 

defined as one with characteristics that are similar to the new vehicle, only not equipped 

with efficiency-improving technologies (or they are de-activated). 

Thus, for this rulemaking ARB is proposing to require that automobile manufacturers 

use the AC17 test procedure to demonstrate the effectiveness of their A/C efficiency 

technologies. Although USEPA will be seeking comment on the AC17 test in the Notice 

of Proposed Rulemaking for their 2017-2025 MY light-duty Greenhouse Gas Program

that may result in some minor changes to the test procedure, staff believes that the 

basic procedure is sufficiently complete for ARB to propose it as a replacement for the 

Idle Test beginning in 2017, as a prerequisite for generating efficiency credits. Staff 

proposes that the LEV III/GHG regulatory proposal, as part of the Advanced Clean Cars 

rulemaking package, be finalized with the final federal AC17 test procedure and credit 

qualification requirements, provided these are substantially similar to that described 

herein and in Appendix R. ARB staff anticipates that USEPA will incorporate the AC17 

test and associated requirements if the 2017-2025 MY rulemaking is finalized as 

scheduled in 2012, at which time the finalized federal regulatory language, as modified 

for California, would be subject to additional public comment before being incorporated 

into the finalized LEV III/GHG rule. If the finalized federal regulatory language cannot 

be incorporated into California’s LEV III/GHG rule before it is finalized, ARB staff 

proposes that AC17 test procedure as currently proposed in the “California 2015 and 

Subsequent Model Criteria Pollutant Exhaust Emission Standards and Test Procedures 

and 2017 and Subsequent Model Greenhouse Gas Exhaust Emission Standards and 

Test Procedures for Passenger Cars, Light-Duty Trucks, and Medium-Duty Vehicles” 

(Appendix D) be used to qualify for efficiency credits, with the final federal test 

procedures possibly being incorporated into LEVIII through a subsequent Board action 

in order to promote harmonization within the national program.

Alternative fuel vehicles: ARB staff is proposing to credit electric- and hydrogenpowered vehicles according to their incremental emission impact from Californiaspecific low-GHG upstream energy sources that are most likely in the timeframe of the 

regulation. Advanced electric-drive vehicles, including plug-in hybrid electric vehicle, 

battery electric vehicle, and fuel cell electric vehicle technology, can be driven primarily 

or entirely without tailpipe CO2 emission emissions. Their associated GHG emissions 

are, instead, upstream from the vehicle at primary energy processing facilities, at 
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electricity generation plants, and throughout the fuel and electricity distribution network. 

In order to structure the GHG program for the long-term for a diversity of vehicle fuel 

types, the regulation proposes the implementation of standards that incorporate the 

relative GHG emissions from battery electric vehicle, plug-in hybrid electric vehicle, and 

fuel cell electric vehicle technologies as compared to the conventional vehicles that 

primarily utilize gasoline. The intent then is to establish straightforward performancebased GHG emission provisions that accurately count the upstream emissions in a 

technology-neutral way that provides industry certainty to plan for GHG requirements as 

these more advanced ultra-low-GHG technologies enter the market.

Staff notes that its proposed crediting provision for battery electric vehicle, plug-in hybrid 

electric vehicle, and fuel cell electric vehicle technology differs from the expected 

federal USEPA GHG regulatory program, which ARB intends to deem as sufficient for 

overall compliance. To accommodate this difference, staff is proposing two compliance 

options: (1) an automaker chooses to comply directly with California’s standards 

including upstream accounting as specified here or (2) an automaker chooses to comply 

with the federal USEPA standards; utilizes the federal accounting provisions for battery 

electric vehicle, plug-in hybrid electric vehicle, and fuel cell electric vehicle technologies 

in the federal standards; and receives the same federal accounting for these 

technologies within the California regulation. 

Staff’s non-zero-emission accounting for these technologies’ incremental upstream 

emissions is justified for several reasons. Primarily, the ZEV regulation already requires 

electric-drive vehicles in California, therefore obviating the need for special artificial 

crediting incentives. In addition, ARB’s proposed GHG crediting more accurately 

depicts the science regarding known GHG impacts, more adequately sets the precedent 

for a future with increasingly more alternative fuel vehicles for 2025 and beyond, more 

assuredly protects against the environmental repercussions of foregone GHG emissions 

allowed from battery electric vehicle emission incentives, and better continues ARB’s 

objective in keeping its performance standards technology-neutral. In addition, this 

accounting reflects California’s purpose and intent to evaluate and reduce all GHG 

emissions – beyond tailpipe CO2 – from all principal phases of passenger motor vehicle 

powering and use. Nevertheless, staff notes that accepting federal compliance (i.e., 

with federal upstream crediting incentives) remains valid, owing to the 50-state GHG 

reduction benefit greatly outweighing the California-alone GHG standard compliance, 

thus achieving additional emissions reductions benefiting California.

The ARB staff position on incorporating the incremental upstream emissions of electric 

and hydrogen fuel cell vehicles is further justified by several California-specific details 

that are different from the national US situation. The greater deployment of these 

advanced technologies in California fundamentally differentiates the State from the US 

context. The California ZEV regulation as proposed for amendment mandates that over 

10% of the new vehicle fleet be some form of battery electric vehicle, plug-in hybrid 

electric vehicle, or fuel cell electric vehicle technology in 2025. In addition, California 

has complimentary programs (e.g., Low Carbon Fuel Standard and Renewable Portfolio 

Standard) that reduce upstream GHG emissions over time, rigorously track these 
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emissions, and provide the basis for accurate GHG emissions accounting. According to 

staff analysis below, for California’s relatively low-GHG electricity and hydrogen, these 

ZEV-type vehicles will achieve very low GHG emission ratings and therefore would 

naturally achieve substantially lower GHG emissions than any other known vehicle 

technologies (e.g., hybrids) by a large margin without artificial incentives. 

The GHG ratings for the three major electric-drive vehicle types involve several main 

factors. First, automaker vehicle testing of these vehicles’ energy consumption 

characteristics under the customary city and highway drive cycles is required. For 

battery electric vehicles and plug-in hybrid electric vehicles, energy use is tested in 

kilowatt-hours per mile. For fuel cell electric vehicles, energy consumption is measured 

in kilograms of hydrogen per mile. Second, the energy consumption data are used to 

calculate these vehicles’ relative GHG emissions, based on the projected future 

California-specific energy mix and related upstream GHG emission impacts. The 

upstream GHG factors are based on emission factors that are consistent with other 

known California electric grid and hydrogen production technology and policy 

developments for the 2020-2025 timeframe, to account for when these vehicle 

technologies will be entering the fleet in larger numbers. To allow for industry certainty 

in compliance planning, the upstream GHG emission factors are to be fixed for the 

entire 2017-2025 period of the GHG regulations. The GHG accounting equations, 

described below, that apply to these electric-drive technologies are conceptually 

identical to those in the federal 2012-2016 GHG rulemaking (that would be used after 

the initial federal incentives are utilized), but use California specific life-cycle GHG 

factors.

The upstream electric vehicle factors are based on the expected 33% renewable 

electricity mix in California, based on the implementation of 2011 California Senate Bill 

2. The California grid is currently powered by an approximate 20% renewable energy 

mix, and the future mix in the 2020 timeframe is expected to reach 33% renewable, 

according to the in-development regulation of the California Public Utilities Commission. 

The detailed technical work from that process is utilized here to determine a consistent 

grid CO2 emission rate (see EEE, 2010a; 2010b). From that analysis, the GHG 

emissions from future electricity use on the California grid are found to be 226 gCO2 per 

generated kilowatt-hour. Upstream electricity emission factors to account for 

powerplant fuel transportation, feedstock, and processing GHG emissions, as well as 

electricity transmission and distribution efficiency losses, are taken from the Low 

Carbon Fuel Standard (LCFS) analysis (CARB, 2009a). After inclusion of the primary 

feedstock energy GHG emissions for powerplant (i.e., at 10% of overall electricity GHG) 

from the powerplant and the transmission and distribution losses (i.e., of 8%), the 

upstream electricity GHG factor is found to be 270 gCO2e/kWh (i.e., 226 * 1.10 / 0.92) 

to deliver the electricity to a final vehicle user as measured at the electrical plug.

GHGEV = (270 gCO2e/kWh) * EEV – Gupstream

The equation is used for both the city and highway drive cycles, and EEV is measured 

directly from each cycle for each test vehicle of battery electric vehicle technology in 
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units of kilowatt-hours per mile (per SAE J1634). The cycle results are combined (as for 

all other vehicles) for 55% city and 45% highway driving. The Gupstream factor is applied 

to account for the reduction in well-to-tank gasoline GHG emissions. This adjustment 

factor effectively translates the lifecycle battery electric vehicle crediting into the 

regulation that only accounts for the direct tailpipe, or tank-to-wheels GHG emissions. 

Based on the LCFS lifecycle modeling of gasoline, upstream gasoline emissions are 

equivalent to 2211 gCO2e/gallon of gasoline, as compared to the direct tailpipe 8887 

gCO2e/gallon as used in the regulation. As a result the equivalent gasoline emissions 

that are upstream can be calculated by multiplying the tailpipe GHG emissions by 25% 

(i.e., the upstream gasoline factor [2211], divided by direct exhaust factor [8887]). As in 

the federal GHG 2012-2016 regulations, this upstream gasoline adjustment is indexed 

to vehicles’ target GHG emission rate (as described above). For example, a battery 

electric vehicle in California with a footprint of 42 ft2 with a GHG emission target of 200 

gCO2/mile GHG emission target would have an upstream gasoline adjustment factor of 

50 gCO2/mile. In later years with lower GHG targets, the factor becomes lower (e.g., 40 

gCO2/mi for a 160 gCO2/mi target).

Gupstream = (Target gCO2/mile) * (0.25)

The GHG crediting of plug-in hybrid electric vehicles involves the measurement of 

electricity consumption and direct tailpipe CO2 emissions throughout the full range of 

the vehicle (where it alternately uses grid electricity and consumes gasoline). Plug-in 

hybrid electric vehicles use the same upstream electricity GHG factor as above for their 

upstream electricity use during the regulatory test cycles. The fraction of their driving 

percent that is attributed to electricity is to be set according to the SAE J2841 utility 

factor, which indexes the fraction of electric miles to the amount of daily miles. This 

method results in a 20-mile all-electric plug-in hybrid achieving a utility factor of 0.40 

and a 40-mile all-electric plug-in hybrid achieving a 0.63 utility factor, corresponding to 

40% and 63% equivalent electric driving, respectively. The precise plug-in hybrid 

testing procedures are more complex, involving the testing through successive city and 

highway cycles, as described in ARB’s hybrid testing procedures, and involve utility 

factor calculations for each subsequent successive city and highway cycles. 

For fuel cell electric vehicles, the GHG crediting involves the direct test cycle 

measurement of hydrogen and the applicable upstream emission factors for hydrogen 

delivered to California vehicle users. The upstream GHG factors for hydrogen fuel are 

based on the expectation of 33% renewable hydrogen (based on the proposed Clean 

Fuels Outlet regulation, Senate Bill 1505 of 2006, and the ZEV program’s fuel cell 

electric vehicle projections) and an upstream emission factor consistent with the Low 

Carbon Fuel Standard (CARB, 2009b) accounting for hydrogen fuel. Staff projects that 

with fuel cell electric vehicle deployment from the ZEV program, along with the 

provisions of the Clean Fuels Outlet regulations proposed for amendment as part of this 

Advanced Clean Cars package and SB1505, hydrogen will move to 33% renewable 

sources within the 2017-2025 timeframe. As a result, the LCFS-derived GHG 

emissions factor for 33% renewable hydrogen of 9,132 gCO2e/kilogram hydrogen is 

applied to the rulemaking’s crediting of fuel cell electric vehicles. As above for electric 
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vehicles, the fuel cell electric vehicle crediting equation includes the gasoline upstream 

adjustment factor to bring the lifecycle GHG crediting into the tank-to-wheel GHG 

standard. The GHG rating for fuel cell electric vehicles is calculated as follows, based 

on the hydrogen consumption (HFCV) in kilograms of hydrogen per mile.

GHGFCV = (9132 gCO2e/kg H2) * HFCV – Gupstream

In order to provide context for the proposed GHG crediting of battery electric vehicle, 

plug-in hybrid electric vehicle, and fuel cell electric vehicle technologies, approximate 

GHG emission ratings for three currently available models are shown here. Included 

are three example vehicles: an battery electric vehicle at 0.24 kWh/mile (similar to a 

Nissan Leaf); a plug-in hybrid electric vehicle with 0.25 kWh/mile, a 0.63 utility factor, 

and 177 gCO2/mile exhaust emissions (similar to a Chevrolet Volt); and a fuel cell 

electric vehicle with 87 miles per kilogram hydrogen (similar to a Honda FCX Clarity). 

The GHG crediting of these hypothetical vehicles is shown in Table III-A-5-4. As shown 

all three vehicles would achieve GHG ratings that would give them substantial emission 

reductions within the GHG crediting framework for California described above, even 

after factoring in the reduced GHG of all conventional vehicles against which the three 

vehicles are being compared. The GHG ratings for these current electric-drive vehicle 

models would be 80-93% below current 2008 technology, 73-91% below 2016 

technology, and 69-89% below 2020 technology, respectively. Further efficiency 

improvements from these current electric-drive technologies (e.g., low rolling resistance 

tires, mass-reduction, improved aerodynamics, improved accessory loads, low-GHG air 

conditioning systems), would result in greater percent GHG effectiveness than the 

reductions shown here when compared to conventional gasoline vehicles.

Table III-A-5-4. Example GHG emission rating from electric-drive vehicles

Technology

Electric 

energy use 

(kWh/mi)

Utility 

Factor

Direct 

CO2

emissions 

(gCO2/mi)

Hydrogen 

use 

(mi/kg)

GHG rating 

(gCO2e/mi)

Reduction in GHG 

emissions versus average 

new vehicle

In 

2008

In 

2016

In 

2020

Electric vehicle 0.240 - - - 23 93% 91% 89%

Plug-in hybrid electric 

vehicle (40-mile) 0.252 0.63 177 - 67 80% 73% 69%

Fuel cell vehicle - - - 87 65 81% 74% 70%

Notes: Upstream GHG emissions based on California 2020 and beyond characteristics for electricity and hydrogen 

production, and gasoline upstream adjustment, Gupstream, of 40 gCO2/mi is assumed for avoided equivalent upstream 

gasoline usage; use of air-conditioning credits not included; Average assumed new vehicle in California 336 gCO2/mile in 

2008, 251 gCO2/mile in 2016, and 215 gCO2/mile in 2020

Off-cycle credit: ARB staff is proposing to adopt the same off-cycle crediting 

provisions as USEPA at this time and revise, as needed, to maintain alignment with the 

federal program in future years. The federal USEPA program developed off-cycle 

crediting provisions for the 2012-2016 rules, and the provisions are being further 

developed for the 2017-2025 program. The major modification for the 2017-2025 
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regulations is to provide manufacturers with a list of pre-approved technologies for 

which USEPA can quantify a default value that would apply (unless the manufacturer 

demonstrates to USEPA that a different value for its technology is appropriate). The 

default values have been determined from the USEPA light-duty vehicle simulation tool, 

based on state-of-the-art full-vehicle simulation modeling of the physical principles 

throughout the various vehicle subsystems. The first application of the vehicle 

simulation model has been peer-reviewed and published (Lee et al, 2011; USEPA, 

2011), and the tool is publically available. Conceptually this is similar to the “menudriven” approach as utilized in the air conditioning provisions. Staff notes that the 

amount of default GHG credit allotted in these crediting provisions is conservative.

Similar to the air-conditioning credit provisions, these optional provisions can be used to 

offset some tailpipe emissions and thus provide additional flexibility for achieving 

compliance with the CO2 standards. Any vehicle model or vehicle test family receiving 

off-cycle credits from the various approved technologies can receive a maximum of 10 

grams CO2 per mile in credits. This accounting reflects California’s purpose and intent 

to evaluate and reduce all GHG emissions – beyond tailpipe CO2 – from all principal 

phases of passenger motor vehicle powering and use. Through these off-cycle credit 

provisions, ARB staff is also integrating vehicle thermal control innovations that had 

formerly been considered in the Cool Cars rulemaking. 

Table III-A-5-5 provides estimates for the GHG emission credits that are expected to 

have default credit values. With these provisions, ARB staff acknowledges the 

importance of off-cycle CO2-emission reductions that verifiably occur in real world 

conditions but are not acknowledged in standard test-cycle CO2 measurement. 

Examples of these off-cycle technologies include active grill shutters that improve 

aerodynamics at high vehicle speeds, solar panels that significantly offset accessory 

electric loads and/or charge hybrid and electric-drive batteries, and solar control glazing 

that reduces the load from air conditioning. ARB staff notes that these estimations for 

available off-cycle crediting may be further refined after USEPA’s final rulemaking in 

2012.
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Table III-A-5-5. Estimates of off-cycle GHG credit from pre-approved technology

Technology Car credit 

(gCO2/mile)

Truck credit 

(gCO2/mile)

High-efficiency headlights 1.1 1.1

Engine heat recovery 0.7 0.7

Solar roof panels 3.0 3.0

Active aerodynamic improvements 0.6 1.0

Engine stop-start 2.9 4.5

Electric heater circulation pump 1.0 1.5

Active transmission warm up 1.8 1.8

Active engine warm-up 1.8 1.8

Thermal control (e.g., solar control) and 

Thermal comfort (e.g., ventilated seats) Up to 3.0 Up to 4.3

Full-Size pickup truck technology: ARB staff is proposing to adopt the USEPA fullsize pickup truck incentive provisions. The full-size pick-up provisions provide special 

emission-reduction credit for technology innovations on the largest of pickup trucks that 

fall within the light-duty vehicle regulations, in order to facilitate the widespread 

deployment of technologies that are likely to otherwise remain in relatively small 

numbers. These full-size pickup crediting provisions have minimum truck capacity 

criteria (i.e., minimum pickup bed dimensions and minimum payload requirements), 

minimum company pickup truck penetration requirements, and technology-based 

criteria. The provisions will have two technology types (hybrid and non-hybrid 

performance-based) and two levels (10 and 20 gCO2e/mile). Of the four potential 

mechanisms to receive the full-size pickup truck credits, no model can receive credit 

under more than one of the mechanisms. The pickup truck definition and the four 

applicable provisions are summarized in Table III-A-5-6. 
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Table III-A-5-6. Summary of provisions for hybrid and performance-based full-size 

pickup truck credits

Provision Minimum qualifying criteria, conditions

Full-size pickup truck 

definition (for any 

qualifying pickups)

•Minimum cargo bed width between the wheelhouses of 48 inches (defined by dimension 

W202 in Society of Automotive Engineers Procedure J1100)

•Minimum cargo bed length of 60 inches (defined by dimension L505 in Society of Automotive 

Engineers Procedure J1100)

•Minimum towing capability (gross combined weight rating, minus gross vehicle weight rating) 

of 5000 lb; or minimum payload capability (gross vehicle weight rating, minus curb weight) of 

1700 lb.

Performance-based 

full-size pickup (10 

gCO2/mi)

•Satisfy full-size pickup truck definition (see above)

•Available for model years 2017-2021

•Maximum gCO2/mile of 15% below GHG target for given year and footprint

•Once test model achieves credit for given model year, it can receive credit in subsequent 

years, provided no increase in gCO2/mile

•The level of gCO2/mile emission performance must be achieved on a minimum percent of all 

the company’s full-size pickup trucks sold in each model year that it is to receive credit: 15% 

in 2017; 20% in 2018; 28% in 2019, 35% in 2020, 40% in 2021.

Performance-based 

full-size pickup (20 

gCO2/mi)

•Satisfy full-size pickup truck definition (see above)

•Available for model years 2017-2025

•Maximum gCO2/mile of 20% below GHG target for given year and footprint

•Once test model achieves credit for given model year, it can receive credit for four additional 

model years (but not beyond model year 2025), provided no increase in gCO2/mile

•The level of gCO2/mile emission performance must be achieved on at least 10% of all the 

company’s full-size pickup trucks sold in each model year that it is to receive credit.

Mild hybrid full-size 

pickup (10 gCO2/mi)

•Satisfy full-size pickup truck definition (see above)

•Minimum recovery of 15% of the theoretical available braking energy as electrical battery 

energy (as determined by vehicle test weight and A, B, and C test coefficients, and USEPA 

equations for total net energy in to battery divided by total braking energy on FTP city cycle)

•Technology must be used on a minimum percent of all the company’s full-size pickup trucks 

sold in each model year that it is to receive credit: 30% in 2017; 40% in 2018; 56% in 2019, 

70% in 2020, 80% in 2021.

Strong hybrid full-size 

pickup (20 gCO2/mi)

•Satisfy full-size pickup truck definition (see above)

•Minimum recovery of 75% of the theoretical available braking energy as electrical battery 

energy (as determined by vehicle test weight and A, B, and C test coefficients, and USEPA 

equations for total net energy in to battery divided by total braking energy on FTP city cycle)

•Technology must be used on at least 10% of all the company’s full-size pickup trucks sold in 

each model year that it is to receive credit

N2O and CH4 provisions: ARB staff is proposing to change the regulatory 

requirements for CH4 and N2O emissions. In the Pavley 2009-2016 GHG regulation, 

the standard was expressed as a CO2-equivalent, including the emissions of CO2, 

refrigerant HFC, and CH4 and NO2. These last two GHG pollutants were assigned 

default CO2-equivalent emission factors that automakers could accept and include in 

lieu of separate certification testing for each test vehicle. As such these two pollutants 

were included in the baseline and in future compliance as default values (unless 

companies opted to submit measured data instead). Under the federal 2012-2016 

rulemaking, USEPA established regulations whereby CH4 and N2O emissions are 

regulated by maximum per-vehicle emission caps with required N2O and CH4 emission 

test data submissions from model year 2015 on. 

ARB staff proposes to adopt the federal USEPA model year 2016 per-vehicle regulatory 

caps for its 2017-2025 regulations for CH4 and N2O emissions. As a result, testing for 

these two emissions will be required from model year 2017 on by vehicle type, with full 

useful life certification limits of 0.030 g/mi CH4 and 0.010 g/mi N2O. Considering that 

vehicles are typically designed at about 50% below the emission limits to meet 
Page 142

standards for vehicle production variability and deterioration, these proposed CH4 and 

N2O standards reflect the same stringency as the existing California default standards. 

Under the existing California standards the default CH4 and N2O values would not have 

prevented the possibility of outlier vehicles or un-tested and un-monitored vehicles that 

have CH4 and N2O emission levels that creep up over time. This proposed mandatory 

testing approach more adequately protects against backsliding and the potential that 

high-emitting outlier vehicles could otherwise utilize ARB’s default values. 

ARB staff proposes to allow manufacturers to over-comply with CO2 standards and use 

those over-compliance credits to offset any N2O or CH4 emission deficits. A 

manufacturer choosing this option would convert its measured N2O and CH4 test results 

that are above the applicable standards into CO2-equivalent emissions, according to 

their global warming potential (GWP) values (i.e., GWP of 25 for CH4, GWP of 298 for 

N2O) to determine the amount of required CO2 emission credits. For example, a

manufacturer would use 0.25 g/mile of positive CO2 credits to offset 0.01 g/mile of

negative CH4 credits or use 2.98 g/mile of positive CO2 credits to offset 0.01 g/mile of

negative N2O credits.

This revised approach – unbundling the regulated GHG formula but providing credit for 

reducing individual vehicular GHGs – avoids having to adjust the CO2 footprint curves 

to reflect the other two pollutants, as would have been required in the bundled approach 

that sums CO2, N2O, and CH4 emissions. However, in the potential event that federal 

GHG standards were not being accepted for equivalent compliance, ARB staff would 

consider revising the GHG standards back to a bundled approach that directly sums 

tested CO2, N2O, and CH4. This, in turn, would require the adjustment of the footprintindexed GHG target standards from those that are proposed here. 

For inventory purposes, ARB staff will convert the emission levels to CO2-equivalent 

rates based on their GWP values. With a GWP of 25, the CH4 limit equates to 0.75 

gCO2e/mile; with a GWP of 298, the N2O limit equates to 2.98 gCO2e/mile. For a new 

model year 2016 vehicle with test cycle GHG emissions of 250 gCO2/mile, with the N2O 

and CH4 emissions at a 50% design target, the total GHG emissions from the three 

pollutants would be 251.87 gCO2e/mile (i.e., 250+1.49+0.38). In this case, the 

contribution of the N2O and CH4 would be less than 1% (i.e., [1.49+0.38]/[251.87]) of 

the new vehicle test-cycle GHG emissions. For average new 2025 vehicles at about 

166 gCO2e/mile, N2O and CH4 would still amount to less than 1.5% of test cycle GHG 

emissions. Because these emission levels are very low, and because these particular 

emissions are expected to continue to be very tightly controlled as part of the LEV III 

SULEV 2015-2025 standards for oxides of nitrogen and hydrocarbons, staff believes it 

is not necessary to establish more stringent standards for these two GHG pollutants. 

Still, setting a cap, and maintaining a potential footprint adjustment, reflects California’s 

purpose and intent to evaluate and reduce all GHG emissions – beyond tailpipe CO2 –

from all principal phases of passenger motor vehicle powering and use.
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5.4. Compliance with the Greenhouse Gas Requirements

Staff assesses the required technology penetration and expected compliance cost 

based on the California vehicle fleet projection, the GHG standard and ZEV program 

requirements, and the available technology packages’ CO2 effectiveness and 

incremental prices as projected above. The GHG standards are, by design, 

performance standards and therefore allow many potential compliance paths to be 

undertaken by any company depending on their particular mix of vehicle types and 

technology competencies. This analysis investigates compliance paths that incur low 

average cost per vehicle, given the available technologies.

Fundamentally, this compliance analysis has three scenarios that are summarized here: 

(1) a “no new policy” baseline, (2) 2017-2025 GHG standards without new 2018-2025 

ZEV requirements, and (3) 2017-2025 GHG standards with new 2018-2025 ZEV 

requirements. The first scenario is modeled in order to investigate the cost of the 

already adopted 2016 GHG standards and the existing ZEV requirements to serve as a 

reference from which to compare the additional technology costs from the new GHG 

standards and ZEV program. The second and third scenarios help show the differential 

cost between the GHG program alone versus the LEV III GHG standards with the ZEV 

program as a package. The additional compliance cost from the regulatory proposal 

package, then, is the third scenario minus the baseline first scenario. 

The analysis of the baseline for no new LEV III and ZEV policy includes approximately 

constant GHG emissions for 2016 and later model years. This 2017-and-beyond 

baseline includes no new concerted industry action to further reduce average GHG 

emissions, but it does include some small changes from the slight projected car-truck 

shift and the requirements for model year 2017-2018 ZEV regulation compliance. Staff 

believes that the historical trends for automaker compliance with criteria pollutant and 

CAFE standards, feedback from discussions with automakers, and the effect of 

footprint-indexed standards make it clear a “flat” future year baseline is the highest 

likelihood reference scenario. For example, as indicated in the USEPA Trends report 

and other technical analyses, when model year 1986-2005 CAFE standards remained 

unchanged, new vehicle fuel economy also remained essentially unchanged while new 

technologies were utilized to improve other vehicle attributes (USEPA, 2010; Lutsey and 

Sperling, 2005; An and DeCicco, 2007). Similarly, staff has found no evidence of 

sustained over-compliance with its criteria pollutant standard regulations when 

standards are unchanged. From feedback from automakers, staff believes that the 

advent of footprint-indexed standards of 2012-2016 will make it further unlikely that 

there will be any significant GHG over-compliance in the absence of the proposed new 

GHG standards.

As indicated in the representative technology package walk-ups in Figure III-A-4-5 and

III-A-4-6 above, the general progression of GHG-reduction technologies goes from early 

engine and transmission technologies (aerodynamics, low rolling resistance tires, dual 

cam phasing, 8-speed and dual clutch transmission, engine friction reduction), to mass 

reduction of about 10%, to turbocharged downsized direct injection engines, to cooled 
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exhaust gas recirculation, to more advanced mass reduction of 15-20%, to hybrids, to 

electric-drive technology. The increasing GHG standard stringency through the 2017-

2025 standard period generally moves each automaker through this technology 

progression toward more advanced technologies at higher incremental cost over time. 

However, with the proposal for new 2018-2025 ZEV regulation requirements the 

strategic technology choices could be impacted to result in a greater penetration of 

ZEV-type vehicles, reducing the penetration of the other more incremental technologies.

The proposed changes for the ZEV regulation are posted in a separate Initial Statement 

of Reasons (ISOR) that is released concurrently with this one for LEV III. Although the 

proposed ZEV regulations have crediting provisions that allow for many different battery 

electric vehicle, plug-in hybrid electric vehicle, and fuel cell electric vehicle technology 

deployment strategies for compliance, the ZEV analysis has resulted in a “most likely” 

scenario for the projected technology mix. The basic technology shares are shown here 

in Table III-A-5-7, as they are analyzed in this assessment of the GHG-plus-ZEV 

compliance scenario. For further ZEV program details, crediting provisions, and 

requirements, readers are directed to the ZEV regulation ISOR30.

Table III-A-5-7. Projected new vehicle technology shares of ZEV-type vehicles

Manufacturer 

type

Vehicle 

type

Existing Proposed

2012-2014 2015-2017 2018 2019 2020 2021 2022 2023 2024 2025

BEV 0.13% 0.50% 0.9% 1.7% 2.3% 2.8% 3.2% 3.6% 3.8% 3.8%

Large 

volume FCV 0.06% 0.17% 0.2% 0.4% 0.6% 0.9% 1.3% 1.7% 2.1% 2.6%

PHEV 1.5% 2.0% 3.6% 4.3% 5.0% 5.7% 6.4% 7.1% 7.9% 8.6%

Intermediate 

volume PHEV - - 6.4% 10.0% 13.6% 17.1% 20.7% 24.3% 27.9% 31.4%

Technology penetration: Figure III-A-5-4 illustrates ARB staff’s estimated technology 

penetration for compliance with the 2017-2025 GHG standards. Relatively low cost 

aerodynamic and low rolling resistance tires are adopted sooner, followed by 

progressive introduction of dual-clutch transmissions, turbo-downsized gasoline direct 

injection, mass-reduction, cooled exhaust gas recirculation, and electric-drive (including 

hybrid, plug-in hybrid, electric, and fuel cell) technologies. ARB staff projects that the 

turbo-downsized gasoline engine becomes the major engine technology over this 

period, with more advanced cooled EGR engines with even greater boosting emerging 

in the later years of the standards. For the case of the proposed GHG standards (i.e., 

without ZEV), the higher cost hybrid and ZEV-type technologies are needed for 

compliance at a level of about 12% market share by 2020 and by 16% in 2025, and 

about two-thirds of those vehicles are hybrids. A number of technologies like engine 

 30STAFF REPORT: INITIAL STATEMENT OF REASONS, ADVANCED CLEAN CARS, 2012 PROPOSED 

AMENDMENTS TO THE CALIFORNIA ZERO EMISSION VEHICLE PROGRAM REGULATIONS, Release Date 

December 8, 2011.
Page 145

friction reduction, optimized transmission controls, improved accessory efficiency, and 

dual-cam-phasing, which are on most of the packages, are not shown in the figure. 

Although the use of a low-GWP refrigerant, like HFO-1234yf, is expected to see some 

deployment before the 2017-2025 period, staff projects its widespread application from 

2016-2021.

Figure III-A-5-4. Technology penetration for 2017-2025 MY GHG standards (without new 

2025 ZEV)

Table III-A-5-8 shows more detailed results for the technology penetration in 2016, 

2020, and 2025 for the two compliance scenarios. As indicted above, compliance with 

the GHG standards without the ZEV program would require that hybrid and ZEV-type 

vehicles make up about 12% by 2020 and 16% in 2025 (with about two-thirds of those 

vehicles being hybrids). Under the ZEV scenario, these advanced vehicles would 

represent vehicle shares of 14% in 2020 and 22% in 2025 (with about two-thirds of 

those vehicles being ZEV-type vehicles). As a result of the impact of the additional 

ultra-low-GHG ZEV technologies toward GHG compliance, the required shares of 

incremental engine, transmission, and hybrid technologies are reduced in the 2021-

2025 timeframe. For example, where the GHG-only scenario found 72% of model year 

2025 vehicles would be turbocharged downsized gasoline direct injection, in the “with 

ZEV” scenario, that technology deployment dropped to 51%. Staff notes that the 

expected technology shares in an overall national US sales context is somewhere 

between these two scenarios, where California and ZEV-adopting states get more ZEVheavy sales mixes and ZEVs contribute toward the GHG standard compliance of the 

overall US fleet.
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Table III-A-5-8. Percent of new vehicles with given technology for GHG and GHG-plusZEV compliance scenarios

Scenario Technology Percent of vehicles with technology by model year

2016 2020 2025

GHG regulation

Aerodynamics (10%+) 61% 79% 100%

Low RR tires (10%+) 61% 79% 100%

Mass reduction (10%+) 11% 32% 58%

Dual clutch transmission 38% 48% 62%

Gasoline direct injection 33% 50% 72%

Cooled EGR 0.2% 14% 32%

Hybrid 4.5% 7.5% 11.3%

Plug-in hybrid electric vehicle 1.7% 2.0% 1.9%

Electric vehicle 0.4% 1.7% 1.8%

Fuel cell vehicle 0.1% 0.5% 0.9%

Alternative refrigerant 0% 100% 100%

GHG and ZEV 

regulations

Aerodynamics (10%+) 61% 79% 100%

Low RR tires (10%+) 61% 79% 100%

Mass reduction (10%+) 11% 27% 46%

Dual clutch transmission 38% 47% 56%

Gasoline direct injection 33% 41% 51%

Cooled EGR 0.2% 6% 14%

Hybrid 4.5% 5.2% 5.7%

Plug-in hybrid electric vehicle 1.7% 5.4% 9.3%

Electric vehicle 0.4% 2.3% 3.7%

Fuel cell vehicle 0.1% 0.6% 2.5%

Alternative refrigerant 0% 100% 100%

The summary results shown above in Table III-A-5-8 represent two scenarios for 

compliance to achieve the required regulatory GHG levels in the new California fleet. In 

the national US fleet context, a compliance scenario could resemble technology shares 

from each of those two scenarios that are shown. Automakers will be able to use ZEVtype vehicles (for California and ZEV-adopting Section 177 compliance) toward 

compliance with national USEPA GHG standards. California and other ZEV-adopting 

states31 amount to about 29% of US light-duty vehicle sales. As a result, ZEV 

requirements in ZEV states alone would amount to a minimum of about 4% national US 

share for all ZEV types. The non-ZEV technology shares, nationally and in California, 

could be more similar to the “GHG only” scenario (e.g., over 70% GDI and over 10% 

hybrid shares). As a result, staff believes that it is possible that selling the required ZEV 

shares in California, along with a nationally compliant GHG fleet, could deliver some 

amount of over-compliance with the GHG standards within California. However, it is 

uncertain exactly if or how automakers might choose to differentially sell various vehicle 

technology types across California and the rest of the US. 

Price of compliance: Due to the incremental price increases associated with the 

technologies that are used toward compliance, the average vehicle is projected to 

experience increasing vehicle prices through the vehicle rulemaking period. Assuming 

that all of the associated direct manufacturing and indirect cost mark-ups are passed on 

to consumers, Table III-A-5-9 summarizes the incremental vehicle price increase that 

 31 Currently Arizona, Connecticut, Maine, Maryland, Massachusetts, New Jersey, New Mexico, New York, Oregon, 

Rhode Island, and Vermont.
Page 147

results from the GHG emission standards over the 2017-2025 period. The GHG 

standards are estimated to cost approximately $1340 per vehicle by the final model year 

of the program, with approximately equal average per-vehicle costs across the car and 

truck categories. Due to the higher cost of electric vehicle technology associated with 

the ZEV-type vehicles, the compliance costs of the GHG-plus-ZEV scenario increase 

from $1340 to around $1840 per vehicle in model year 2025. Because staff estimates 

that the vast majority of the ZEV technology will be utilized in cars, the cost burden 

varies between cars and trucks, with approximately $2490 on average for cars and 

$810 on average in trucks by 2025. For context, as shown above on a technology basis 

(see section III.A.4.4) and below in consumer economic analysis, the lifetime benefits of 

the vehicles will on average have benefits that greatly exceed the these incremental 

costs. 

Table III-A-5-9. Incremental vehicle technology price ($/vehicle) for 2025 GHG regulations

Scenario Category 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025

GHG regulation

Car - 170 330 520 720 900 1,070 1,190 1,310 1,320

Truck - 170 340 510 720 910 1,090 1,200 1,310 1,360

Average - 170 340 510 720 910 1,080 1,190 1,310 1,340

GHG and ZEV 

regulations

Car - 160 460 930 1,270 1,700 2,020 2,300 2,560 2,490

Truck - 160 250 340 420 530 610 670 730 810

Average - 160 380 700 940 1,230 1,460 1,660 1,840 1,840

All value rounded to the nearest ten.

The above table represents the average costs according to the major vehicle 

categories. In order to arrive at those cost estimates, the analysis incorporated 

compliance by all the major companies with the GHG and ZEV standards, in order to 

investigate differences in the companies’ average per-vehicle cost of compliance due to 

their baseline fleet characteristics. To analyze each case, after companies meet their 

ZEV requirements, low-GHG technology packages are added in order of their costeffectiveness (moving up in cost per GHG reduction per mile) until companies’ new 

vehicle fleets come into compliance with the GHG standards.

Table III-A-5-10 summarizes the incremental price increase results for major automobile 

manufacturers to comply with the GHG and ZEV regulations. In the table, the baseline 

represents a fleet without new policy, meaning compliance with 2016 GHG standards 

and the existing ZEV regulation. As shown in the table below, the average per-vehicle 

incremental price increase differs by automaker. Companies with relatively low GHG 

baseline fleets (e.g., Honda, Hyundai-Kia, Mazda, and Toyota) have lower-than-average 

incremental prices. Companies that typically have larger sales percentages of luxury 

and high-performance models (e.g., BMW, Jaguar-Land Rover, Mercedes, Spyker, 

Volvo, and Volkswagen) have higher estimated compliance costs. 
Page 148

Table III-A-5-10. Summary 2025 MY of increased incremental price for baseline, 2025 

GHG regulation, GHG-plus-ZEV regulation scenarios

Company

Incremental price in 2025 

from 2008 technology

Incremental price in 2025 

from Baseline

Baseline 2025 GHG 2025 GHG+ZEV 2025 GHG 2025 GHG+ZEV

BMW 1,020 2,530 3,250 1,500 2,230

Chrysler-Fiat 1,270 2,350 2,870 1,080 1,600

Ford 1,260 2,710 3,220 1,440 1,960

General Motors 1,080 2,470 2,840 1,390 1,760

Honda 1,050 1,910 2,480 860 1,430

Hyundai-Kia 1,000 1,890 2,510 890 1,520

Jaguar-Land Rover * 1,670 5,410 5,870 3,740 4,200

Mazda 910 2,080 2,610 1,170 1,700

Mercedes 1,550 4,450 4,500 2,900 2,950

Mitsubishi * 720 2,900 3,940 2,180 3,230

Nissan 980 2,430 2,650 1,450 1,670

Spyker * 1,110 4,310 5,230 3,200 4,130

Subaru * 670 1,990 4,470 1,320 3,800

Suzuki * 710 2,920 3,880 2,210 3,160

Toyota 1,240 2,270 2,850 1,030 1,610

Volvo * 960 3,820 5,340 2,860 4,380

Volkswagen 1,370 3,660 3,750 2,280 2,370

Average 1,150 2,490 2,990 1,340 1,840

Notes: Costs are in the year 2025 in 2009 dollars; This baseline includes compliance with 2016 GHG standards and projected 

baseline ZEV requirements (i.e., before new 2018+ MY ZEV proposal) of about 2% PHEV, 1.7% BEV/FCV shares from 2017-

2015; (*) indicates companies that are likely to be allowed Intermediate Volume Manufacturer (IVM) PHEV-only provisions 

within ZEV program 

The above summary tables illustrate the incremental price to consumers in model year 

2025, the final year of the proposed standards. The phase-in schedules for each of the 

programs are summarized above (i.e., ZEV market shares, and GHG footprint-indexed 

targets). Based on the phase-in schedules, the incremental technology costs (with 

varying levels of technology cost learning through those interim years) are analyzed 

through each year of the program. 

Figure III-A-5-5 illustrates the summarized staff technical analysis on the incremental 

price increase due to the GHG and ZEV programs. As indicated in the table above, 

these price increases are incremental to the existing GHG and ZEV regulations. The 

figure shows the GHG program’s incremental increase from 2016 through 2025, as well 

as how the higher incremental cost of ZEV technology adds additional cost due to their 

still relatively low manufacturing volumes. The final average incremental vehicle price 

increase for the GHG standards plus ZEV package is shown increasing from $0 in 2016 

to $1840 in model year 2025. This average price increase shown includes the 

approximate 15% share of ZEVs that are higher cost (at $8000+ price premium) as well 

as the non-ZEVs (that more typically have an approximate $1000 price premium). In a 

national context, these compliance results would differ somewhat. A comparable 2017-

2025 national compliance assessment would not include California’s baseline ZEV 

regulation requirement, would not require the new proposed 2025 ZEV shares, and 

would involve some smaller differences in the fleet mix. However, the ZEV-type 

vehicles in California (and Section 177 states) will all aid in national USEPA GHG 
Page 149

standard compliance. As a whole, the average per-vehicle price premium overall that is 

associated with the 2025 federal standards is expected to be similar to the $1840 result 

here for California compliance.

Figure III-A-5-5. Incremental vehicle price for GHG and ZEV programs, relative to no new 

policies beyond model year 2016

5.5. Discussion of Differences from 2010 Joint-Agency TAR and this Analysis 

by ARB

As outlined above, there have been many updates to the technical and cost analysis 

since ARB, USEPA, and NHTSA jointly published their interim TAR on GHG 

technologies in September of 2010. This section offers a high level summary of 

substantial differences in the results, as well as a description of the major underlying 

reasons for the differing results. Essentially nearly every technical change made in our 

assessment of GHG-reduction technologies, including technology effectiveness, 

technology availability, and technology costs, was discussed jointly between the 

technical staffs of ARB, USEPA, and NHTSA. These changes, along with a number of 

California-specific assumption modifications, are summarized here.

There were numerous analytical modeling differences in this work from the TAR. One 

primary change has been in the CO2 effectiveness modeling. The Ricardo vehicle 

simulation modeling offered a state-of-art technical analysis of emerging highly 

advanced powertrain technologies. The modeling ultimately indicated that a greater 

CO2 effectiveness of several percentage points would result from emerging incremental 

technologies – in particular from more advanced direct injection engines with greater 

levels of turbocharging and cooled exhaust gas recirculation technologies and a number 

of other engine and transmission technologies. 

Another modeling modification was to use results from NHTSA’s new 2011 fleet safety 

analysis to impose constraints for per-vehicle mass-reduction across vehicle classes in 
Page 150

a way that was deemed “safety-neutral.” As a result, smaller cars were not allowed any 

mass reduction, mid-size cars were allowed up to 10% mass reduction, and the trucks 

were allowed up to 20% mass reduction. Although the 2011 NHTSA fleet modeling 

showed fatality coefficients that were statistically insignificant in four out of five cases, 

their suggested safety modeling constraints were imposed for all vehicle classes in 

order to conservatively model technical compliance scenarios that minimize societal 

safety risks. Ultimately this safety-neutral constraint greatly reduced the total massreduction projected to be utilized in automaker 2025 compliance from levels of 15-30% 

in the TAR to approximately 9% in this updated ARB staff modeling. Based on 

feedback from automakers that are reducing mass across all their vehicle platforms and 

from various vehicle safety design studies’ validation of mass-reduced advanced vehicle 

designs, ARB staff has found that these safety-neutrality constraints are conservative 

assumptions about the use of safe mass-reduction technology that will likely be utilized 

for compliance with the standards. Nevertheless, it is clear that the proposed 

regulations do not require mass reduction beyond expected manufacturer shifts.

Several changes have also been made in the provisions for evaluating the GHG 

crediting provisions for air conditioning system improvements. The TAR analyzed a 

maximum of 15 gCO2e/mi to be utilized industry-wide in the 2020-2025 timeframe. In 

this analysis for the proposed standards, the available GHG credits from air-conditioning 

systems are higher. For this proposal the maximum available credits are higher at 18.8 

gCO2e/mi for cars and 24.4 gCO2e/mi for trucks (for approximately 21 gCO2e/mi on 

average, depending on the fleet mix). This effectively allows an additional 6 gCO2e/mile 

from the various refrigerant and air conditioning efficiency technologies that were not 

available in the TAR analysis. 

A number of analytical changes have been made in this updated assessment of various 

technologies’ incremental costs. Generally, the methods for using FEV teardownderived costs (with agency estimates of indirect costs of the technologies) increased 

due to small detailed modifications to account for engineering design and testing and 

the potential for stranded capital costs. Also, the new FEV cost study offered some 

increased and some decreased costs of various hybrid components but on the whole 

substantially increased the incremental hybrid costs to generally $4000-$5000 over 

baseline 2008 technology. Mass reduction costs also increased substantially based on 

the agencies’ assessment, thereby reducing the relative attractiveness of using 

optimized design and advanced materials (See Appendix Q for a related discussion). 

There were also minor changes in supplier cost estimates on various components. For 

battery electric vehicle and plug-in hybrid electric vehicle technologies, battery costs 

have been adjusted upward to account for safety disconnect equipment and thermal 

management systems. Overall the indirect cost multipliers saw adjustments in their 

magnitude and in the placement of technologies into the ICM categories, thus resulting 

in higher indirect cost mark-ups for the costs of nearly all of the technologies.

The technical and compliance cost modeling has now separately been conducted by 

each of the agencies with company-specific impacts examined. The company-specific 

modeling allows for greater detail on technologies and costs of industry compliance and 
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more detailed consideration by each agency for its particular regulatory requirements. 

The separate modeling by each of the agencies (whereas the TAR compliance 

modeling was led by USEPA) allows for varying agency provisions and requirements, 

as well as providing independent agency review and development of their respective, 

proposed standards. For example, the agencies have differing regulatory treatment of 

alternative fuel vehicles and air-conditioning credits (i.e., between NHTSA standards 

and the GHG standards), and California has to separately account for the requirements 

of the ZEV program, as discussed above.

A number of California-specific factors result in further differences from the TAR 

compliance results. There are some basic differences due to California-specific 

assumptions about the projected fleet mix. For example, even with exactly the same 

footprint-indexed standard lines, the California fleet has a 166 gCO2/mile standard 

target, compared to the federal fleet’s projected 163 gCO2/mile target outcome. The 

largest factor in this difference is California’s projection for 61% cars and 39% trucks 

versus the federal projection of 68% car and 32% truck. For context, California’s fleet in 

model year 2008 had a 60% car share, and the recent US new vehicle fleet had a 50-

53% car share in 2005-2008 and 59-60% car share in 2009-2010. The federal sales 

projection from the TAR incorporates a contracted industry sales projection from CSM 

and the US Energy Information Administration’s Annual Energy Outlook projections. 

ARB’s projection is based on California Department of Motor Vehicle data and statewide 

vehicle population and travel trends as consistent with ARB’s EMFAC statewide 

modeling. Also, California has other small differences in the projected fleet mix, 

including different company percent shares and small differences in the footprintindexed vehicle fleet size. Staff has analyzed the sensitivity of the overall GHG 

program outcome for shifts in these vehicle sales trends below in section III.A.5.9, 

finding them to be significant and important to track in future years.

California’s ZEV program imposes requirements for increased sales of battery electric 

vehicle, plug-in hybrid electric vehicle, and fuel cell electric vehicle technology. The 

larger amount of ZEV technology in California, as well as other well-established lowGHG programs (e.g., Low-Carbon Fuels Standard, Renewable Portfolio Standard) 

tracking those upstream emissions, prompted Staff to directly consider the upstream 

GHG emissions of these vehicles in the fleet emission rates, whereas the TAR did not. 

ARB’s proposal, rationale, and GHG rating equations for these ZEV-type technologies 

are discussed above in section III.A.5.3. 

Table III-A-5-11 summarizes the results of this assessment in the context of ARB, 

USEPA, and NHTSA interim TAR analysis in September 2010. Aside from the abovementioned differences in the modeling, there are additional differences in the 

assumptions applied for vehicle consumer lifetime usage and fuel price. The TAR used 

survival-adjusted lifetime travel assumptions that were approximately 200,000 miles per 

vehicle, based on national data for vehicle travel and survival rates. This assessment 

relies on California-specific data on vehicle travel and survival rates from the California 

Department of Motor Vehicles. Basic summary tables here utilize California-specific 

data for median vehicle lifetimes of 14 years and 186,000 miles for cars and 17 years 
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and 234,000 miles for trucks. Staff notes that, by definition, half of new vehicles will 

travel more or less than these average lifetime estimates. Also the TAR applied future 

gasoline prices that were approximately $3.49/gallon from the US Department of 

Energy’s Annual Energy Outlook. This assessment applies projections for California 

fuel prices that are somewhat higher, at, for example, $4.02 in 2025 (year 2009 dollars) 

based on the California Energy Commission’s Integrated Energy Policy Report (CEC, 

2011).

Table III-A-5-11. Summary of the proposed standard compliance technology and cost 

versus joint-agency TAR findings from September 2010

Scenario Technology 

Path

New Vehicle Technology Penetration in 2025 Incremental 

price 

($/vehicle)

Average 

payback 

period 

(yr)

Net liftetime 

owner 

savings ($)

Mass 

Reduction

Gasoline 

& diesel 

vehicles

HEV PHEV EV, 

FCV

Path A 15% 89% 11% 0% 0% 930 1.6 5000

TAR Path B 18% 97% 3% 0% 0% 850 1.5 5100

3%/year Path C 18% 97% 3% 0% 0% 770 1.4 5200

Path D 15% 75% 25% 0% 0% 1050 1.9 4900

Path A 15% 65% 34% 0% 0% 1700 2.5 5900

TAR Path B 20% 82% 18% 0% 0% 1500 2.2 6000

4%/year Path C 25% 97% 3% 0% 0% 1400 1.9 6200

Path D 15% 55% 41% 0% 4% 1900 2.9 5300

Proposed 

regulation

(4.5%/yr)

GHG 9.3% 84% 11% 1.9% 2.7% 1,340 2.1 5,900 

GHG+ZEV 8.3% 79% 5.7% 9.3% 6.2% 1,840 2.8 5,100 

Path A 15% 35% 65% 0% 1% 2500 3.1 6500

TAR Path B 20% 56% 43% 0% 1% 2300 2.8 6700

5%/year Path C 25% 74% 25% 0% 0% 2100 2.5 7000

Path D 15% 41% 49% 0% 10% 2600 3.6 5500

Path A 14% 23% 68% 2% 7% 3500 4.1 6200

TAR Path B 19% 48% 43% 2% 7% 3200 3.7 6600

6%/year Path C 26% 53% 44% 0% 4% 2800 3.1 7400

Path D 14% 29% 55% 2% 14% 3400 4.2 5700

5.7. Analysis of Alternative GHG Regulation Stringency

In addition to the proposed GHG regulatory stringency of above, staff also analyzed 

alternative stringencies that delivered lower and higher GHG emission levels. The 

differing stringency levels were based upon the upper bounds that were chosen by 

USEPA, NHTSA, and CARB for use in the 2010 TAR analysis. The reduced stringency 

case represented a 3%/year reduction in GHG emissions from 2016-2025 to achieve 

190 gCO2e/mile; the increased stringency case represented a 6%/year GHG reduction 

to achieve 143 gCO2e/mile in model year 2025. 

Staff notes that NHTSA, in its Environmental Impact Statement, has decided to analyze 

a range of scenarios that spans from 2%/year to 7%/year in annual fuel economy 

increase. Staff notes that ARB’s technical analysis from the TAR effectively narrowed 

the GHG stringency range to within 3-6%/year change in CO2 emissions, due primarily 

to ARB Pavley requirements for meeting the various technical, economic, and owneroperator life-cycle cost factors. As a result the 3-6%/year range from the TAR was 
Page 153

maintained for this analysis of alternatives. The sufficiency of these upper and lower 

ranges for ARB’s analysis of alternatives in its Environmental Analysis is discussed in 

that document, Appendix B. 

In order to analyze the two alternative stringency cases, footprint-indexed GHG target 

lines were shifted downward from model year 2016 target lines to achieve the 3%/year 

(for the “lesser stringency alternative”) and 6%/year (for the “greater stringency 

alternative”) new vehicle fleet GHG emission rates for model years 2017 through 2025. 

Figure III-A-5-6 shows the two alternatives that were considered for lesser and greater 

GHG stringency. The proposal, as described above, takes the fleet from 251 gCO2/mi 

in model year 2016 to 166 gCO2/mile in 2025. The lesser stringency case, at a 3% per 

year reduction in GHG emissions, would result in a 191 gCO2/mile emission rate, and 

the greater stringency case, at a 6% per year reduction, results in 144 gCO2/mile. 

Figure III-A-5-6. Proposed model year 2017-2025 GHG standards, with alternative 

stringency cases

Table III-A-5-12 shows the differing levels of technology deployment that would be 

projected under the lesser, proposed, and greater GHG stringency alternatives for 

model years 2016, 2020, and 2025. As described above, under the proposal scenario 

for GHG and ZEV implementation, advanced hybrid and electric-drive vehicle 

technologies would represent shares of 14% in 2020 and 22% in 2025. For the lesser 

GHG stringency case, the projected amounts of these advanced technologies would 

drop to 12% in 2020 and 19% in 2025. Under the greater GHG stringency case, the 

shares of these advanced technologies would increase to 19% in 2020 and 31% in 

2025. Similarly the amounts of conventional technology (e.g., direct injection, mass 

reduction, cooled EGR) would be reduced in the lesser GHG stringency case and 

increased in the greater GHG stringency case. 
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Table III-A-5-12. Percent of new vehicles with given technology for proposal compliance 

scenario – and lesser and greater GHG stringency alternatives

Scenario Technology Percent of vehicles with technology by model year

2016 2020 2025

Alternative: 

Lesser stringency 

(3%/year) GHG 

regulation

Aerodynamics (10%+) 61% 77% 93%

Low RR tires (10%+) 61% 77% 93%

Mass reduction (10%+) 11% 13% 16%

Dual clutch transmission 38% 43% 47%

Gasoline direct injection 33% 30% 27%

Cooled EGR 0.2% 1% 1%

Hybrid 4.5% 3.8% 3.2%

Plug-in hybrid electric vehicle 1.7% 5.4% 9.3%

Electric vehicle 0.4% 2.3% 3.7%

Fuel cell vehicle 0.1% 0.6% 2.5%

Alternative refrigerant 0% 100% 100%

Proposed GHG and 

ZEV regulations 

(~4.5%/year GHG 

reduction from 

2016-2025)

Aerodynamics (10%+) 61% 79% 100%

Low RR tires (10%+) 61% 79% 100%

Mass reduction (10%+) 11% 27% 46%

Dual clutch transmission 38% 47% 56%

Gasoline direct injection 33% 41% 51%

Cooled EGR 0.2% 6.3% 14.5%

Hybrid 4.5% 5.2% 5.7%

Plug-in hybrid electric vehicle 1.7% 5.4% 9.3%

Electric vehicle 0.4% 2.3% 3.7%

Fuel cell vehicle 0.1% 0.6% 2.5%

Alternative refrigerant 0% 100% 100%

Alternative: 

Greater stringency 

(6%/year) GHG 

regulation

Aerodynamics (10%+) 61% 81% 100%

Low RR tires (10%+) 61% 81% 100%

Mass reduction (10%+) 11% 39% 67%

Dual clutch transmission 38% 50% 61%

Gasoline direct injection 33% 55% 76%

Cooled EGR 0.2% 18% 35%

Hybrid 4.5% 10.0% 14.4%

Plug-in hybrid electric vehicle 1.7% 5.4% 9.3%

Electric vehicle 0.4% 2.7% 4.4%

Fuel cell vehicle 0.1% 0.7% 2.6%

Alternative refrigerant 0% 100% 100%

Figure III-A-5-7 illustrates the resulting overall incremental price increase due to the 

proposed regulatory GHG standards, along with the lesser and greater GHG stringency 

cases. The three cases incorporate the implementation of the ZEV regulation, along 

with conventional and hybrid gasoline technologies, to achieve compliance with the 

varying GHG stringency levels. The figure shows the incremental price increase from 

the proposed regulations from 2016 through 2025, when the total projected GHG-plusZEV price increase is $1840 per vehicle. Also shown is the lesser and greater 

stringency cases that result in approximately $1370 and $2630 incremental price 

increases per vehicle, respectively. These average price increases include the ZEVs 

that are higher cost (at a $8000+ price premium) as well as the non-ZEVs (that more 

typically have an approximate $1000 price premium). The staff GHG proposal, at 

approximately a 4.5%/year annual stringency over the 2016-2025 period, was ultimately 

determined based on meeting the joint statutory requirements of USEPA, NHTSA, and 

ARB; discussions with the automobile industry; and achievement of the maximum 

feasible cost-effective GHG emission reduction level.
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Figure III-A-5-7. Incremental vehicle price for GHG-plus-ZEV programs for proposed 

regulation and two alternative GHG stringency cases (relative to no new GHG and ZEV 

policies beyond model year 2016)

5.8. Analysis of Vehicle Manufacturing GHG Emissions

Staff has analyzed the potential effect that the technologies promoted by the standards 

could have GHG impacts outside of their immediate test cycle and fuel production GHG 

emissions. In particular, the standards will promote a variety of mass-reduction 

technologies that could introduce advanced materials (e.g., high-strength steel and 

aluminum) that have differing manufacturing GHG emissions compared to conventional 

vehicle materials that are now in use. In addition, the GHG standards and the ZEV 

program will promote increased use of batteries and other electric-drive components 

that might have different manufacturing GHG impacts. 

As identified above, the mass of vehicles designed to meet the standards are projected 

to reduce by about 9% on average in the 2020-2025 timeframe. Because of the 

footprint-indexed design of the standards, this level of mass-reduction is expected to 

result from the use of advanced materials and optimized vehicle design and without 

requiring vehicle shifts in size, class, or utility. 

Figure III-A-5-8 shows the spread of available data on production cycle GHG emissions 

to manufacture vehicles of different technologies with data from three sources (Kim et 

al, 2010; ANL, 2007; Patterson et al, 2011). The data have been normalized to an 

average 3700-lb vehicle curb weight in order to represent the approximate average 

vehicle in the California (and US) new vehicle fleet. The amounts and types of 

technology considered by staff in this analysis for 2025 vehicles are generally within the 

“conventional mass-reduction” part of the data (primarily new steel and aluminum parts), 

and therefore have no clear manufacturing GHG difference from the baseline. Hybrid 

and electric-drive vehicles appear to potentially add several tons per vehicle of 

production-cycle GHG emissions.
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Figure III-A-5-8. Vehicle production cycle GHG emissions from various technologies

Figure III-A-5-9 puts these manufacturing GHG emission results in context of the 

lifetime GHG emissions of a vehicle. The lifetime GHG emissions from the lifetime 

operation of a model year 2008 baseline vehicle are about 66 tons CO2e at the vehicle 

tailpipe (plus another 16 tons in the upstream fuel processing upstream), as compared 

to their manufacturing GHG emissions at roughly 6-8 tons. Greater use of high-strength 

steel and aluminum to achieve the modest reductions in vehicle weight projected to 

comply with the proposed GHG standards may not increase production-cycle 

emissions, as indicated by the literature above. Although electric-drive technologies 

may increase manufacturing emissions by several CO2e tons per vehicle, these 

technologies’ substantially reduced operating emissions will more than offset the 

increase in manufacturing emissions, as shown in Figure III-A-5-9. The figure also 

includes upstream fuel production emissions based on California LCFS assumptions for 

gasoline and future electricity and hydrogen, as previously discussed. Although the 

upstream manufacturing cycle emissions are uncertain, this assessment suggests that 

manufacturing cycle emissions’ vehicle contribution as a percentage of total vehicular 

GHGs could approximately increase from roughly 8% today to roughly 15% for new 

vehicles in 2025 (i.e., for the GHG plus ZEV scenario). 
Page 157

Figure III-A-5-9. Vehicle use, upstream fuel, and production cycle GHG emissions of an 

average mid-size vehicle 

5.9. Sensitivity Analysis

One uncertainty of the GHG standard outcome is due to the inherent regulatory 

structure, though history suggests that appropriate safeguards can be developed to 

ensure projected GHG reductions. Because the standards have two categories with 

different standards and footprint-indexed standards for each category, different 

compliant 2025 fleet mixes would have substantially varying final gCO2/mile outcomes. 

ARB staff has analyzed the potential for a varying outcome of the standards based on 

shifts in the car-truck mix and shift in the fleet-average footprint size (within the car and 

truck categories). These category and size trends are of interest because these factors 

can tend to shift over time based on fuel prices, larger economic trends, and automobile 

manufacturing and marketing trends. In addition, ARB staff is cognizant of the potential 

for strategic re-categorization of crossover vehicle models that exhibit many car-like 

features but could be increasingly categorized as trucks (for example based on the 

presence of four-wheel drive, or a third row of seats). This is an increasing potential 

concern over time, especially because the truck standards receive less-stringent 

percent GHG reductions from 2016 to 2025 than the car standards. Figure III-A-5-10

illustrates the difference in the footprint-indexed standards for cars and trucks in 2025. 

These standards effectively permit 29-30 gCO2/mile less stringent standards for the 

smallest trucks that are primarily car-platform-derived crossover models (e.g., Honda 

CR-V, Toyota RAV4, Ford Escape). For example, a 45-ft2 crossover would have a 144-

gCO2/mile standard target as a car and a 174-gCO2/mile standard if classified as a 

truck.
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Figure III-A-5-10. Difference between car and truck GHG standard target lines in model 

years 2016 and 2025

Figure III-A-5-11 summarizes the ARB staff analysis of potential fleet trends that could 

result from modest footprint and category shifts over the rulemaking period. To 

examine the potential future mix of the car-truck split, ARB considers 70% cars (the 

highest national car share since 1988) as a reasonable upper bound. In the other 

direction, ARB staff considers 55% trucks as a potential upper bound (based on 52% 

national light-duty truck share in 2004). There is only limited available data from 2008-

2010 on average new vehicle footprint, since the footprint-indexed standards have only 

recently taken effect. With limited data, modest and plausible shifts in average new 

vehicle footprint (ft2

) by 0.2% per year are considered here in the staff analysis. The 

new vehicle fleet footprint and car-truck mix shifts, in turn, result in greater or lesser 

GHG targets, according to where the vehicle models fall on the footprint-indexed GHG 

target lines. The result of plausible long-term footprint and car-truck category trends 

would be to shift the reference case 166 gCO2/mile 2025 standard target up to 179 

gCO2/mile (a 16% loss in GHG reductions from the 2016 level) or as low as 157 

gCO2/mile (a 11% increase in GHG reductions from the 2016 level).
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Figure III-A-5-11. Potential shift in the projected fleet GHG emission outcomes based on 

trends in vehicle footprint and category mix

Based on this analysis, ARB staff considered various anti-backsliding provisions within 

the regulations. The intent of any such alternative anti-backsliding provisions would be 

to not allow overwhelming consumer trends (and automakers’ influence on them) or 

automaker attempts to strategically “game” the regulation’s flexibility for GHG regulatory 

advantage that would undermine the program’s intended GHG benefit. The primary 

mechanisms for potential program GHG emission losses include the potential shift to a 

higher truck sales share and increases in average car and truck footprint. As a result, 

per-company anti-backsliding provisions could be structured and triggered in the event 

of a company surpassing threshold upsizing trends in these two areas. For example, 

hypothetically, if a company’s fleet shifts by over a 5% truck share (e.g., from 45% truck 

to 50% truck) or if sales-weighted car or truck footprint shifted upward by 5% (e.g., from 

40 ft2 to 42 ft2

) the alternative standards could be triggered. The alternative antibacksliding provisions could be structured to disallow any further GHG regulatory 

advantage for surpassing any such hypothetical car-truck or footprint upsizing 

thresholds. Such a provision would ensure the highest GHG emission scenario (i.e., 

with a 16% loss in intended GHG emission reduction) in the above figure could not be 

realized.

ARB staff is not proposing anti-backsliding provisions at this time. As a result of ARB’s 

investigation of the potential for consumer trends and strategic re-categorization of 

crossover cars as trucks over time, ARB is inclined to follow these trends and 

categorization shifts closely in years ahead. ARB staff notes that many, but not all, 

automakers indicated that they are not intending to shift their sales upward in size or 

category over the rulemaking period through 2025. Nonetheless, the extent to which 

the future fleet trends move toward larger average vehicle sizes and/or more trucks than 

projected in this analysis could significantly undermine the expected GHG benefits. 

ARB staff proposes to require detailed certification data reporting on new vehicle 

attributes in order to closely follow these trends. Staff proposes to report to the Board 

on a periodic basis to the extent to which there are significant deviations from the 

projected fleet size and category mix. This requirement would remain even if ARB 
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decides to allow manufacturers to use compliance with national standards to satisfy 

ARB requirements in the 2017 through 2025 timeframe.

ARB staff notes that its use of GHG ratings that integrate electric-drive vehicles into the 

standards according to their incremental upstream GHG emissions differs from the 

expected federal program. The USEPA GHG program has proposed that battery 

electric vehicle, plug-in hybrid electric vehicle, and fuel cell electric vehicle technologies 

be credited for compliance purposes as if they had zero GHG emissions for model 

years 2017-2021, and USEPA would apply sales caps after which automakers would be 

required to count non-zero upstream emissions for later years. The proposed federal 

sales caps would allow up to 600,000 ZEV-type vehicles per manufacturer to be 

credited as having 0 g/mi GHG emissions in 2022-2025 model years (see USEPA and 

NHTSA, 2011b for details). Within a national context there are expected to be 

significantly lower shares of electric and fuel cell vehicles than in California, and 

therefore the potential for lost program GHG emission reductions due to an artificial 

credit incentive is lower in percentage terms. Also, there are higher national grid GHG 

emissions, and therefore any non-zero upstream crediting serves as a lesser relative 

incentive for battery electric vehicle and plug-in hybrid electric vehicle deployment than 

the proposed ARB GHG crediting based on California’s low-GHG grid. 

Therefore, crediting these vehicles at 0 gram per mile is being proposed for federal 

GHG regulatory purposes for 2017-2021 (without limits) and for 2022-2025 (with 

company-specific limits). Note that although the emissions are counted in the federal 

regulation as zero gCO2e/mile for compliance purposes, the upstream emissions are 

accounted for separately in the full federal inventory accounting. ARB staff projects that 

with the successful implementation of the ZEV program in California and ZEV-adopting 

Section 177 states, that the federal USEPA caps for zero gCO2e/mile crediting will be 

met before 2025. As described above in the development of the upstream accounting 

provisions, the California context (primarily due to the ZEV regulation) obviates the need 

for advantageous incentive crediting for these ZEV technologies. 

Also, federally, these plug-in hybrid electric vehicle, battery electric vehicle, and fuel cell 

electric vehicle vehicles are granted additional incentives through multipliers (whereby 

each vehicle is counted as more than one vehicle) for 2017-2021, as shown in Table IIIA-5-13. As with the zero upstream crediting, staff is not proposing to include these 

multiplier incentives that will be part of the federal GHG program. These multipliers 

would allow each of these advanced electric-drive vehicles sold to be counted as more 

than one vehicle for compliance accounting purposes. ARB staff proposal does not 

include these multipliers in the calculations for the same reasons that the 0 g/mi ZEV 

crediting is not utilized. In both cases, the existence of the ZEV regulation along with 

low California upstream emissions eliminate the need to provide such incentives that do 

not directly result in further GHG reductions.
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Table III-A-5-13. Federal advanced electric-drive vehicle technology multiplier incentive

Technology 2017 2018 2019 2020 2021 2022-2025

Plug-in hybrid vehicle 1.6 1.6 1.6 1.45 1.3 1.0

Electric vehicle 2.0 2.0 2.0 1.75 1.5 1.0

Fuel cell vehicle 2.0 2.0 2.0 1.75 1.5 1.0

In addition, ARB staff is proposing to adopt the special pickup truck incentive credits of 

10 and 20 gCO2/mile (for hybrid and non-hybrid innovations). ARB staff has analyzed 

these provisions in order to evaluate the relative national GHG program losses 

associated with the use of these technology incentives toward automaker compliance. 

The 0 gCO2/mi provision results in lost GHG emission reductions on account of the 

ignored upstream GHG emissions associated with the primary fuel transportation, 

processing, electricity generation, and distribution. The 0 gCO2/mi provision results in 

increasingly greater losses in GHG reductions with greater amounts of battery electric 

vehicles, plug-in hybrid electric vehicles, and fuel cell electric vehicles in the fleet. The 

relatively low upstream GHG emissions in California reduce the extent of the loss from 

this provision from California vehicles. The multipliers mentioned above for these 

electric-drive vehicles would result in program GHG losses through the early program 

years, model years 2017-2021, but without any loss in the overall gCO2/mile outcome in 

model year 2025. The hybrid full-size pickup credit is limited in its potential lost GHG 

emission reduction, because qualifying full-size pickups represent less than 10% of all 

the light-duty vehicles in California.

Table III-A-5-14 summarizes the extent to which the three provisions could affect the 

GHG program outcomes in the new California fleet. The lost GHG program emissions 

from the 0 g/mi battery electric vehicle/plug-in hybrid electric vehicle/ fuel cell electric 

vehicle incentive are estimated according to the GHG upstream emissions those 

vehicles would incur based on California GHG emission factors for 2020 and beyond 

electricity and hydrogen (both 33% renewable sourced). Due to the 0 g/mi incentives, 

the standards that would achieve 4.51%/year GHG emission reductions (without any 

such incentives), are estimated to achieve 4.34%/year, resulting in a 3.7% loss in the 

overall cumulative 2017-2025 GHG reductions that would have been achieved if (a) the 

battery electric vehicle/plug-in hybrid electric vehicle/ fuel cell electric vehicle had true 

upstream accounting or (b) if automakers complied without using any battery electric 

vehicle/plug-in hybrid electric vehicle/ fuel cell electric vehicle technology. The other 

two provisions, the battery electric vehicle/plug-in hybrid electric vehicle/ fuel cell electric 

vehicle multiplier and the pickup truck hybrid credit would have relatively minimal 

potential impact in eroding the intended GHG reductions from the standards over the 

2017-2025 MY period.
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Table III-A-5-14. Potential effect of electric and hybrid vehicle incentives on the California 

fleet

Proposal 

without 

incentive 

provisions

Regulatory incentive provisions

With 0 g/mi 

BEV/PHEV/FCV

With 0 g/mi 

BEV/PHEV/FCV 

and multipliers

With 0 g/mi, 

multipliers, and pickup 

technology credit

Model year 2021 GHG (gCO2e/mi) 201 203 204 204

Model year 2025 GHG (gCO2e/mi) 166 169 169 170

Equivalent average annual GHG 

stringency for model years 2016-2025 4.51% 4.34% 4.31% 4.24%

Cumulative GHG program loss from 0 g/mi - 3.7% - -

Cumulative GHG program loss from 

BEV/PHEV/FCV multiplier - - 0.8% -

Cumulative GHG program loss from 

pickup technology credit - - - 1.6%

Notes: losses from 0 g/mi are compared against the emissions that would have been counted under ZEV deployment with 

California upstream GHG emission factors for 2020 and beyond (i.e., 33% renewable sourced); the pickup technology credit is 

assumed to be utilized by 7% of the fleet for 15 gCO2/mi credit.

5.10. Compliance with the Emission Standards

The proposed climate change emission requirements are comprised of three emission 

standards; a CO2 standard, a CH4 standard and a N2O standard. Whereas more detail 

on a number of the technical provisions was given above, a simplified description of 

compliance with these emission standards is described here. To demonstrate 

compliance with these standards, manufacturers will need to report the CO2, CH4 and 

N2O emissions of their vehicles over the combined city and highway vehicle testing 

drive cycles. The combined city and highway emission value is a weighted emission 

value determined by the following formula:

Combined city/highway emissions = 0.55 x city emissions + 0.45 x highway emissions

CO2 Emission Standard

As described above in section III.A.5.1, the CO2 standards are based on a set of 

footprint curves that assign specific CO2 targets for each vehicle model depending on 

the footprint (the area described by wheelbase times the average track width of the 

vehicle) of the vehicle model. The CO2 targets defined by the footprint curves become 

increasingly more stringent for each model year from 2017-2025. Separate sets of 

footprint curves have been developed for passenger cars and for light-duty trucks. The 

footprint-indexed target lines have “kinks,” whereby all vehicles below a given size each 

receive the minimum target for that year and all vehicles above a given size each 

receive maximum targets for that year. For most vehicles (i.e., those between the GHG 

kinks), the CO2 target is calculated by a simple linear expression and determined by the 

following formula.
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Target gCO2/mile = [a x f] + b

Where: f is the vehicle footprint and coefficients a and b are selected from the 

table of coefficients for the footprint curve for either passenger cars or 

light-duty trucks for the applicable model year.

A manufacturer’s CO2 emission standard is determined by the sales weighted CO2

target for a manufacturer’s vehicle models and will vary between manufacturers 

depending on the specific mix of their vehicle models. Accordingly, a manufacturer’s 

CO2 standard can be expressed with the following formula:

CO2 standard = ∑ CO2 target value x model type production i

0

Total vehicle production

Where: i = each unique combination of model type and footprint value

Model type production = total production of model type/footprint 

Total vehicle production = total production of passenger cars or light-duty 

trucks and medium-duty passenger vehicles, as applicable

To comply with the CO2 standard a manufacturer may certify some vehicle models 

above their CO2 target as long as their excess emissions are offset by vehicle models 

certifying below their CO2 target. The sales-weighted combined test cycle CO2

emissions must ultimately be lower than the automaker’s sales-weighted CO2 standard 

(based on that automaker’s final sales-weighted CO2 targets by footprint) for 

compliance. 

Credits That Can be Applied to the CO2 Standard

Several credits are available that a manufacturer may apply to their measured CO2

emissions. These credits include:

1. Credits for improvements to the vehicle air conditioning system; either from the 

use of a low GWP refrigerant or improvements to the efficiency of the system 

(see Table III-A-4-11 for the maximum CO2e credit values available for air 

conditioning improvements) 

2. Credits for technologies that reduce CO2 emissions but are not measured on the 

applicable test cycles (see Table III-A-5-5).

3. Credits for technology innovations on the largest of pickup trucks (see section 

III.A.5.3).

These credits would be applied to the measured CO2 emissions for each unique 

combination of model type/footprint incorporating these improvements.

Methane and Nitrous Oxide Emission Standards
Page 164

The CH4 and N2O standards are standalone standards. Accordingly, each vehicle must 

meet the standard.

However, manufacturers that over-comply with their CO2 standards may generate CO2

credits to offset any debits generated by N2O or CH4 emissions exceeding the 

applicable standard. A manufacturer choosing this option would convert its measured 

N2O and CH4 emissions that are above the applicable standards into CO2e emissions, 

according to their global warming potential (GWP) values (i.e., GWP of 25 for CH4, 

GWP of 298 for N2O) to determine the amount of required CO2 emission credits. For 

example, a manufacturer would use 0.25 g/mile of positive CO2 credits to offset 0.01 

g/mile of CH4 debits or use 2.98 g/mile of positive CO2 credits to offset 0.01 g/mile of

N2O debits.

IV. CERTIFICATION GASOLINE SPECIFICATIONS

A. PROPOSED AMENDMENTS TO THE SPECIFICATIONS FOR CALIFORNIA 

CERTIFICATION GASOLINE 

The California certification fuel used for testing exhaust and evaporative emissions on 

passenger cars, light-duty trucks, medium-duty vehicles, and heavy-duty gasoline 

engines and vehicles currently contains the oxygenate methyl tertiary butyl ether 

(MTBE) in the quantity of 10.8 to 11.2 volume percent (equivalent to 2.0 percent by 

weight). MTBE was banned for use in California gasoline starting December 31, 2003. 

As a result of the ban of MTBE, ethanol became the prevalent oxygenate used in 

California gasoline. After the ban, refiners began adding approximately 5.7 volume 

percent ethanol to gasoline, which is equivalent to 2.0 weight percent. California 

gasoline contained 5.7 percent ethanol until the end of 2009. In 2010, California 

refiners transitioned to producing gasoline containing 10 percent by volume ethanol 

(E10). Currently, all gasoline in California contains 10 percent ethanol and will continue 

to contain 10 percent ethanol for the foreseeable future. While the oxygenate and 

oxygenate amount have changed in in-use California gasoline, the certification fuel on 

which emission testing is being done has not. Staff is proposing a certification fuel that 

contains 10 percent ethanol and is representative of current in-use fuel. 

1. BACKGROUND

The USEPA reformulated gasoline (RFG) requirements mandated the use of a 

minimum average oxygen content (2.0 percent by weight) year-round in USEPA RFG 

areas. In California, fuel sold in the South Coast, San Diego, San Joaquin Valley, and 

the Sacramento regions must meet federal USEPA RFG requirements, but can do so 

through the use of California reformulated gasoline (CaRFG) because the California 

program produces significantly greater emission reductions than the Federal RFG 

program. These regions account for about 80 percent of the gasoline sold in California.

To comply with the oxygen content requirement, refiners chose to use MTBE.
Page 165

Soon after the implementation of Phase 2 CaRFG, the presence of MTBE in 

groundwater began to be reported. An investigation and public hearings were 

conducted resulting in the issuance of Executive Order D-5-99 on March 25, 1999, that 

directed the phase-out of MTBE in California’s gasoline.

In response to the Governor’s Executive Order, the Board approved the CaRFG3 

regulations on December 9, 1999, and amended them on July 25, 2002. The CaRFG3 

regulations prohibited California gasoline produced with MTBE starting December 31, 

2003; established revised CaRFG3 standards; established a CaRFG3 Predictive Model; 

and made various other changes. The CaRFG3 regulations also placed a conditional 

ban, starting December 31, 2003, on the use of any oxygenate other than ethanol, as a 

replacement for MTBE in California gasoline.

From December 31, 2003 to the end of 2009, California gasoline contained roughly six 

percent ethanol by volume. Beginning in 2010 to the present, California gasoline 

contains 10 percent ethanol by volume. The transition from six percent to 10 percent 

ethanol in California gasoline was due to two major regulations. The Energy Policy Act 

of 2005 (EPAct), among other things, authorized the USEPA to lift the reformulated 

gasoline oxygen content requirement. The removal of the two percent oxygen content 

requirement for USEPA RFG took effect nationwide May 6, 2006. Instead of a minimum 

oxygen content requirement, the EPAct established a renewable fuels standard (RFS) 

that requires increasing quantities of renewable fuels be consumed each year. The 

RFS requirements are expected to push ethanol to 10 percent by volume (E10) in 

gasoline nationwide by 2012.

The other regulation impacting the increase to E10 in California is the 2007 CaRFG 

amendments. In June 2007, ARB amended the CaRFG regulations to require the 

mitigation of emissions associated with permeation from ethanol in gasoline. The 2007 

amendments were set to go into effect beginning December 31, 2009 and refiners found 

that one way to mitigate the emissions associated with permeation from ethanol in 

gasoline was to increase the amount of ethanol in gasoline. Increasing ethanol content 

in gasoline helped to decrease exhaust emissions, which helped to mitigate the 

emissions associated with permeation. With the impending RFS requirements 

increasing to 10 percent ethanol by 2012 and the 2007 CaRFG amendments 

requirements of mitigating emissions associated with permeation, refiners chose to go 

to 10 percent ethanol by volume beginning in 2010. 

The current California certification gasoline properties are shown in Table IV-A-1-1, 

below. The current maximum ethanol content allowed in California gasoline is 10 

percent by volume. California gasoline is expected to be at E10 for the foreseeable 

future, and the certification fuel in California needed to be updated to reflect the in-use 

fuel. The current certification fuel contains MTBE as the oxygenate of the fuel. Since 

MTBE was banned for use in California gasoline in 2003, the current certification fuel is 

not representative of in-use fuel. Staff has developed an E10 certification fuel 

representative of the current in-use fuel.

 
Page 166

Table IV-A-1-1. Current California Certification Gasoline

Fuel Property Limit

Sensitivity (min) 7.5

Distillation Range oF

10 pct. point

50 pct. point

90 pct. point

130-150

200-210

290-300

Sulfur, ppm by wt 30-40

RVP, psi 6.7-7.0

Olefins, vol % 4.0-6.0

Total Aromatic Hydrocarbons, vol% 22-25

Multi-Substituted Alkyl Aromatic Hydrocarbons, vol% (max) 12-14

Benzene, vol % 0.08-1.0

Methyl tertiary-butyl ether (MTBE), vol % (max) 10.8-11.2

Ethanol, vol % --

Total Oxygen, wt% 3.3-3.7

Octane (R+M)/2 (min) 91

Residue, vol% (max) 2.0

Phosphorous, g/gal (max) 0.005

EP, maximum 390

Lead, g/gal (max) (No lead added) 0-0.01

Additives: Sufficient to meet requirements of Title 13, CCR §2257

Copper Corrosion No. 1

Gum, Washed, mg/100 ml (max) 3.0

Oxidation Stability, minutes (min) 1000

Specific Gravity Report

Heat of Combustion Report

Carbon, wt% Report

Hydrogen, wt% Report

2. SUMMARY OF PROPOSED REGULATION

This section presents the staff’s proposed certification gasoline and discusses the 

development of the proposed certification gasoline.

2.1 Proposed E10 Certification Gasoline

The proposed E10 certification gasoline specifications are shown in Table IV-A-2-1, 

below:
Page 167

Table IV-A-2-1. Proposed E10 Certification Gasoline Properties

Fuel Property Limit Test Method(a)

Octane (R+M)/2 87.0-88.4(b) D 2699-88, D 2700-88

Sensitivity (min) 7.5 D 2699-88, D 2700-88

Lead, g/gal (max) (No lead added) 0-0.01 D 3237-79(c)

Distillation Range oF

10 pct. point

50 pct. point

90 pct. point

130-150

205-215

310-320

D 86-99aε1(c)

EP 380-420 D 86-99aε1(c)

Residue, vol% (max) 2.0 D 86-99aε1(c)

Sulfur, ppm by wt 8-11 D 2622-94 or D 5453-93(c)

Phosphorous, g/gal (max) 0.005 D 3231-73(c)

RVP, psi 6.9-7.2 D 323-58(c)

Olefins, vol % 4.0-6.0 D 6550-00(c)

Total Aromatic Hydrocarbons, vol% 19.5-22.5 D 5580-00(c)

Multi-Substituted Alkyl Aromatic 

Hydrocarbons, vol% 

13-15 See method below(d)

Benzene, vol % 0.6-0.8 D 5580-00(c)

Methyl tertiary-butyl ether, vol % (max) 0.05 D 4815-04(c)

Ethanol, vol % 9.75-10.25 D 4815-04(c)

Total Oxygen, wt% 3.3-3.7 D 4815-04(c)

Additives: Sufficient to meet 

requirements of Title 13, CCR §2257

Copper Corrosion No. 1 D 130-88

Gum, Washed, mg/100 ml (max) 3.0 D 381-86

Oxidation Stability, minutes (min) 1000 D 525-88

Specific Gravity Report

Heat of Combustion Report

Carbon, wt% Report

Hydrogen, wt% Report

(a) ASTM specification unless otherwise noted. A test method other than that specified may be used following a 

determination by the Executive Officer that the other method produces results equivalent to the results with the 

specified method. (b) For vehicles/engines that require the use of premium fuel as part of their warranty, the Octane ((R+M)/2) 

becomes a 91 minimum and the rest of the properties are the same. (c) For ease of use, the test methods referred to in Title 13 CCR §2253.4(c) and Title 13 §2263 are labeled on this 

table. The actual certification fuel regulation will make references to the Title 13 CCR §2253.4(c) and Title 13 

§2263 for these test methods. (d) "Detailed Hydrocarbon Analysis of Petroleum Hydrocarbon Distillates, Reformates, and Gasoline by Single 

Column High Efficiency (Capillary) Column Gas Chromatography," by Neil Johansen, 1992, Boulder, CO.
Page 168

There may be certain combination of properties within the proposed certification fuel 

ranges that may not pass the Predictive Model32. To prevent limiting the range of 

properties and to ensure the fuel is compliant with California gasoline regulations, staff 

is proposing that the certification fuel must also pass the Predictive Model. 

2.2. Development of E10 Certification Gasoline Specifications

In order to develop a certification fuel that resembles the in-use fuel, staff used 2010 

Predictive Model gasoline certifications submitted by refiners. The Predictive Model 

gasoline certifications represent the fuel specifications for each batch of fuel the refiner 

is going to produce. In California, there are eight regulated properties of gasoline: Reid 

vapor pressure, aromatics, benzene content, olefin content, sulfur, T50, and T90. Staff 

looked at the average, the standard deviation, and the range of the eight regulated 

gasoline properties to develop the certification fuel. Staff used the average properties 

as a baseline to build the fuel. Staff then entered the properties into the Predictive 

Model to determine ranges that would pass the Predictive Model. Staff attempted to 

keep the properties within the standard deviation of the average, but due to the complex 

relationships between the properties and emissions, some properties were forced to 

stray outside of their standard deviations. Table IV-A-2-2 shows a summary of the 

Predictive Model data used to develop the proposed certification fuel.

Staff also wanted to keep the fuel as near the pass/fail point of the Predictive Model to 

be true to the fuels in the market place. However, because the proposed certification 

fuel specifications provide allowable ranges within which fuel propertied may fall, rather 

than specifying a single allowable value for each property, it was very difficult to develop 

a set of ranges that passed the Predictive Model in all instances without making the 

ranges of the fuel extraordinary lenient and unrepresentative of the in-use fuel. Staff 

compromised and set the ranges of the proposed certification as close to the in-use 

data as possible, while allowing for most combinations of the properties to pass the 

Predictive Model. There are some combinations of fuel properties in the ranges of the 

proposed certification that will not pass the Predictive Model. As a result, staff has 

added the requirement that the certification fuel must be within the proposed ranges and 

must pass the Predictive Model. 

 32 The Predictive Model is a set of mathematical equations that relate emission rates of exhaust hydrocarbons, oxides 

of nitrogen (NOx), and combined exhaust toxic species to the values of eight regulated gasoline properties. [13 CCR 

§2265 (and the incorporated “California Procedures for Evaluating Alternative Specifications for Phase 3 

Reformulated Gasoline Using the California Predictive Model”)]
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Table IV-A-2-2. 2010 Predictive Model Data (Based on 586 Samples)

RVP

(psi)

Aromatics

(vol%)

Benzene

(vol%)

Olefins

(vol%)

Sulfur

(ppmw)

T50

(

o

F)

T90

(

o

F)

Average 7.14 21.11 0.79 6.91 9.01 212.10 315.40

Standard

Deviation 0.62 3.50 0.12 2.22 2.90 13.26 20.33

Range 6.5-7.2 11.2-31.8 0.48-1.1 1-10 2-19 193-220 284-330

2.2.1. Octane Levels

The most common levels of octane grade on the market are 87 anti-knock index (AKI) 

(regular), 89 AKI (mid-grade) and 91-93 AKI (premium) 33. The octane rating of gasoline 

marked "premium" or "regular" is not consistent across the country2. Different states 

define different octane grades for premium gasoline. The octane grade of premium is 

93 AKI in the Federal definition and 91AKI in California. The recommended gasoline for 

most cars is regular octane.

Gasoline with a higher heating value (energy content) provides better fuel economy2

. 

Traditionally, premium gasoline has had a slightly higher heating value than regular, and 

thus provides slightly better fuel economy, although that benefit is difficult to detect in 

normal driving. There can be even larger differences in heating value between batches 

of gasoline from the same refinery, between summer and winter volatility classes, or 

between brands of gasoline from different refineries because of compositional 

differences. The differences are small and there is no practical way for the consumer to 

identify gasoline with a higher-than-average heating value2

.

The higher the octane number in gasoline, the harder it is for the engine to "knock"—an 

unregulated explosion in a chamber designed for highly regulated combustion. Most 

modern cars, however, are designed to employ a specific compression ratio, a measure 

of how much room is available to the fuel/air mixture when the piston is at the bottom 

and the top of the cylinder. This compression ratio tolerates lower octane fuels (such as 

regular gasoline) without knocking34.

Most end users prefer regular gasoline due to its lower price. According to the EIA35, in

California, among the total 5.4 million gallons per day of gasoline sold to end users in 

May 2011, 4.2 million gallons per day of gasoline (77%) were regular, 500 thousand 

gallons per day of gasoline (9%) were mid-grade, and 800 thousand gallons per day of 

gasoline (14%) were premium. Since the certification fuel is intended to represent inuse fuel in California, staff is basing the certification fuel on regular gasoline (87 AKI), 

instead of premium gasoline (91 AKI). For vehicles/engines that require the use of 

premium fuel as part of their warranty, the Octane ((R+M)/2) becomes a 91 AKI 

minimum with the other fuel properties remaining the same.

 33 http://www.api.org/aboutoilgas/gasoline/gasoline-octane.cfm 34 http://www.scientificamerican.com/article.cfm?id=fact-or-fiction-premium-g 35 http://www.eia.doe.gov/dnav/pet/pet_cons_refmg_c_SCA_EPMM_mgalpd_m.htm
Page 170

2.2.2. Multi-substituted Alkyl-Aromatic Hydrocarbons

Staff originally proposed to remove the multi-substituted alkyl-aromatic (MSAA) 

specification for the certification fuel. However, stakeholders provided feedback 

indicating that they would prefer to see the specification remain in the certification fuel 

because it provided a way to ensure that specialty fuel manufactures were using 

refinery feedstocks rather than chemical feedstocks to produce the fuel. In order to 

determine MSAA, one must perform a detailed hydrocarbon analysis (DHA) on the fuel. 

Since DHA is not a standard part of ARB’s fuels enforcement program, the DHA data on 

E10 fuels was limited for this specification. The limited data indicated a range of about 

13-15 volume percent MSAA in the fuels sampled. 

2.2.3. End Point Distillation Temperature

End point (EP) distillation temperature is another specification that is not a standard part 

of ARB’s fuels enforcement program. Data provided by the Alliance of Automobile 

Manufacturers showed a California EP range of about 370-410 degrees Fahrenheit (F), 

with bunching around 380-390. Since measuring EP is not very accurate, staff decided 

to allow for a wider range of 380-420 degrees F for EP to allow for the measurement 

variability. 

2.2.4. Sulfur

The proposed certification fuel range for sulfur is 8-11 parts per million by weight 

(ppmw). An upper limit of 11 ppmw was set because there was no combination of 

properties within the proposed ranges where a sulfur level higher than 11 ppwm would 

pass the Predictive Model. Staff decided to keep the minimum sulfur level at 8 ppmw 

because of the relationship between sulfur and expected NOx emissions. Any value 

below 8 ppmw in combination with properties within the proposed ranges of the 

certification fuel would give abnormally low predicted NOx emissions and thus, would 

not be representative of an in-use fuel.

2.3. E10 Certification Gasoline Application

The proposed E10 Certification Fuel changes apply only to on-road vehicles, excluding 

on-road motorcycles. The California on-road motorcycle regulations, California Code of 

Regulations (CCR), Title 13, section 1958(c), incorporate federal test procedures and 

federal certification exhaust test fuel requirements. The change from Federal Indolene 

test fuel, which is not representative of current commercial fuel, to the new E10 

certification exhaust test fuel for on-road motorcycles will be accomplished in a 

separate, future regulatory action. As with on-road motorcycles, Board consideration of 

a new E10 certification test fuel for spark-ignition, off-road categories (small off-road 

engines, large spark-ignition engines, recreational marine spark-ignition engines, and 

off-highway recreational vehicles) will occur at a separate hearing.

 
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2.4. Implementation

Staff is proposing that the phase-in requirements for E10 certification fuel be consistent 

with the phase-in requirements for LEV III. In addition, staff is also proposing that the 

E10 certification fuel would be available for optional use upon the Office of 

Administrative Law's filing of the LEV III rulemaking with the Secretary of State. 

3. ALTERNATIVES TO THE PROPOSED E10 CERTIFICATION FUEL

 

This section presents an analysis of alternatives to the proposed amendments. The 

only alternative to the proposed certification fuel would be to leave the certification fuel 

unchanged with MTBE as the oxygenate. MTBE was banned for use in California 

gasoline starting December 31, 2003. As a result of the ban of MTBE, ethanol became 

the prevalent oxygenate used in California gasoline. Currently, all gasoline in California 

contains 10 percent ethanol and will continue to contain 10 percent ethanol for the 

foreseeable future. Staff determined that having engines and vehicles certified using a 

fuel that still contains MTBE would misrepresent the expected real-world emissions of 

the engines and could possibly have a negative impact on air pollution in California.36

V. EMISSIONS IMPACTS

A. OVERVIEW OF EMISSIONS INVENTORY METHODS

In California, the EMFAC model is used to assess emissions from on-road passenger 

vehicles. The latest version of the model, EMFAC2011, was released in September 

2011. EMFAC2011 is comprised of three modules; the EMFAC2011-LDV module is 

used to calculate emissions from gasoline vehicles, diesel vehicles <14,000 pounds 

gross vehicle rated weight, urban transit buses, and motorhomes. EMFAC2011-LDV is 

informed by the latest available Department of Motor Vehicles (DMV) registration data, 

and vehicle miles traveled estimates from regional transportation planning agencies 

(RTPA). EMFAC2011-LDV estimates emissions for six vehicle classes that would be 

regulated under the proposed Advanced Clean Cars program, as shown in Table V-A-1. 

 36 State of California, Air Resources Board, Staff Report: Initial Statement of Reasons: Proposed 2007 Amendments 

to the California Reformulated Gasoline Regulations, Release Date: April 27, 2007
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Table V-A-1. EMFAC2011 Light-Duty Vehicle Categories

Vehicle Type Vehicle Class

Gross Vehicle 

Weight Rating

(lbs)

Curb Weight

(lbs)

Passenger Car PC or LDA

Light-Duty Truck 1 LT1 < 6000 <3450

Light-Duty Truck 2 LT2 < 6000 >3450

Medium-Duty Vehicle LT3 / MDV 6000 - 8500

Medium-Duty Truck 4 MT4 / LHDT1 8500 – 10,000

Medium-Duty Truck 5 MT5 / LHDT2 10,000 – 14,000

In the EMFAC model, emissions are calculated as the product of a population of 

vehicles, the number of miles traveled per vehicle, and emission rates for each vehicle 

per mile. This calculation is complex, accounting for the different technologies with 

each model year and vehicle class, the deterioration of emission rates over time and 

miles driven, the difference in miles driven by vehicle class and age, and many other 

factors. The calculation is performed to estimate criteria pollutant emissions including 

reactive organic gases (ROG or NMOG), NOx, CO, and particulate matter (PM); and 

greenhouse gas emissions including CO2, and CH4. For this analysis staff used a 

linear regression relationship to estimate nitrous oxide (N2O) from NOx, since N2O is 

not calculated directly in EMFAC. EMFAC2011-LDV was used as the starting point for 

analyzing emissions for this proposed regulation. To conduct the regulatory analysis, 

staff used EMFAC2011-LDV output to develop several database tools to assess the 

potential emissions impacts of the proposed regulations on a statewide and regional 

basis. 

The methodology used to develop database tools is based on the following equation:

Emissions = POP x TECH x ACCRL x EF

Where:

POP Population of a vehicle of a given vehicle type and model year

TECH The technology fraction (tech fraction) is the fraction of vehicles which 

meets the different emission exhaust standard categories, such as 

super-ultra-low-emission vehicle (SULEV), or ultra-low-emission 

vehicle (ULEV).

ACCRL The annual miles that vehicles travel in a given year

EF A measure of the amount of pollutant released per mile of travel

EMFAC2011-LDV output was separated into these components for each vehicle class, 

each model year (or vehicle age), and each calendar year of interest. The baseline 

inventory was calculated using EMFAC2011, adjusted to reflect our latest assessment 

of baseline technology penetration into the future, and updated with the latest available 

data relevant to PM emission factors. Because EMFAC2011 estimates emissions to 

2035, staff also developed a long-term forecast to estimate emissions from 2035 to 
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2050. Benefits of the proposed regulation were calculated as the difference between 

the adjusted baseline inventory and regulatory scenario inventories. More details are 

available in Appendix T. 

B. ASSESSING BENEFITS OF THE PROPOSED REGULATIONS

The proposed Advanced Clean Cars program contains many elements that will affect 

vehicle tailpipe emissions, including new criteria pollutant emissions standards for 

exhaust and evaporative emissions, new greenhouse gas emissions standards, and a 

mandate that manufacturers sell ZEVs. Under the proposed regulations, both criteria 

pollutant and greenhouse gas emissions standards are fleet average requirements. 

Because standards are fleet average requirements, vehicle manufacturers have the 

flexibility to comply using many different types of technologies in different vehicle 

classes. The ZEV mandate requires that ZEVs will be sold into the fleet, but the ZEVs 

do not provide additional emissions benefits beyond what the fleet average standards 

require. 

To comply with the proposed Advanced Clean Cars regulations, vehicle manufacturers 

must sell a combination of vehicles certifying to specific emissions standards that meet 

a fleet-wide average regulatory target. Several new certification levels have been 

defined in the emissions inventory as potential compliance paths for manufacturers to 

meet the proposed standard. The Advanced Clean Cars program creates additional 

ULEV and SULEV emission certification levels in selected vehicle classes for which no 

testing data are available. To express these new technology groups in the database 

tools, staff used a ratio of standards approach. A ratio of standards approach is a 

technique used to estimate emission factors where no test data are available. For 

example, if exhaust test data are available for ULEV 50 automobiles but not for SULEV 

20 automobiles, unified cycle emission factors in EMFAC for the ULEV category would 

be multiplied by the ratio of standards, in this case 20 mg/mi for SULEV 20 divided by 

50 mg/mi for ULEV 50 to estimate SULEV 20 emission factors.

 

Appendix T provides the assumptions and calculation methodologies for assessing the 

emissions benefits of the proposed regulations.

C. ASSESSING THE IMPACT OF THE REBOUND EFFECT

The rebound effect is the phenomenon whereby consumers utilize some fraction of the 

energy savings from new technology to utilize a greater amount of the particular good 

(e.g., appliance or vehicle). In this case for vehicles, the effect would suggest that the 

demand for driving may marginally increase as the operating costs of the vehicle being 

driven are reduced. When operating costs increase, such as when fuel prices increase, 

driving becomes more expensive and people drive less. Conversely, if fuel prices 

decrease people may drive more. The overall demand for driving is a function of many 

factors including income, fuel prices, the distance between one’s home and job, desired 

discretionary driving, transit options, and many other driving-related costs. Regional 

transportation planning agencies consider these factors that affect travel demand in the 
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aggregate when they estimate regional vehicle miles traveled for the EMFAC model. 

The proposed Advanced Clean Cars regulation would decrease vehicle operating costs 

of travel, as a number of the technologies that will likely be deployed to comply with the 

regulation would decrease the amount of fuel consumed per mile. This effect is 

included in the emissions inventory assessment.

The magnitude of the rebound effect is the subject of extensive academic research, 

which is briefly reviewed in Appendix S. Although federal agencies are applying a 10 

percent rebound to their analysis, ARB’s review of the literature finds the methodology 

developed by Hymel, Small, and van Dender (2010) to be appropriate for projecting 

California-specific estimates of future rebound effects. Based on this method, ARB staff 

estimated future projections of the rebound effect in California through CY2030 for both 

the baseline and policy cases ranging between 3 and 6 percent depending on the year 

and scenario. Staff believes that California’s relatively higher income and congestion 

levels relative to the national average justifies the use of a different rebound 

assumption. California’s relatively higher income and congestion levels relative to the 

national average justify the use of a different rebound assumption. Based on the 

methodology developed by Hymel, Small, and van Dender (2010) using Californiaspecific inputs, ARB staff estimated future projections of the rebound effect through 

CY2030 for both the baseline and policy cases ranging between 3 and 6 percent 

depending on the year and scenario. Further details about the methodology and data 

used to estimate projected rebound levels are presented in Appendix S. These rebound 

effects were then translated into the percentage change in vehicle miles traveled by 

model year and vehicle class for new vehicles sold with and without the proposed 

regulation, based on the estimated percentage decrease in vehicle operating cost. The 

overall percentage increase in model year specific vehicle miles traveled attributable to 

the Advanced Clean Cars regulations ranged from between one and two percent 

depending on the calendar year and scenario. When these rebound rates were 

included in the emissions inventory, there was a loss in the regulations’ overall emission 

reductions of around one percent. 

D. EMISSION BENEFITS OF THE PROPOSED ADVANCED CLEAN CARS 

PROGRAM

Because the proposed Advanced Clean Cars program is in the form of emissions 

standards for new vehicles sold in the future, emissions benefits are initially small and 

increase as new vehicles replace older vehicles in the vehicle fleet. Full benefits of the 

program are seen over 20 years into the future as the California fleet completely turns 

over to Advanced Clean Cars compliant vehicles. 

The Advanced Clean Cars program would provide major reductions in greenhouse gas 

emissions. Figure V-D-1 compares the adjusted baseline CO2 equivalent emissions, 

which include benefits of the federal GHG standard compliance adopted as an option in 

the Pavley regulations, and the Low Carbon Fuel Standard, to estimated emissions 

under the proposed Advanced Clean Cars regulation. Table V-D-1 shows the 

greenhouse gas emission benefits in 2020, 2025, 2035, and 2050. By 2025, CO2
Page 175

equivalent emissions would be reduced by almost 14 Million Metric Tons (MMT) per 

year, which is 12 percent from baseline levels. The reduction increases in 2035 to 32

MMT/Yr which is a 27 percent reduction from baseline levels. By 2050 the proposed 

regulation will reduce emissions by more than 42 MMT/Yr, which is a reduction of 33

percent from baseline levels. Viewed cumulatively through 2050 – and assuming no 

further tightening of the standards after 2025 – the proposed Advanced Clean Cars 

regulation would reduce emissions by more than 870 Million Metric Tons CO2

Equivalent. 

Figure V-D-1. CO2 Equivalent Emission Reductions from Advanced Clean Cars

Regulations
Page 176

Table V-D-1. CO2 Equivalent (CO2e) Emission Benefits from Advanced Clean Cars

Regulations

Statewide CO2e Emissions (Million Metric Tons / Year)

Calendar

Year

Adjusted 

Baseline with 

Rebound

Proposed 

Regulation with 

Rebound

Benefits Percent 

Reduction

2020 111.2 108.1 3.1 3%

2025 109.9 96.3 13.7 12%

2035 114.8 83.2 31.5 27%

2050 131.0 88.3 42.7 33%

Table V-D-2, Table V-D-3, and Table V-D-4 provide the emission benefits (average 

summer day) for calendar years 2023, 2025, 2035, and 2040 for ROG, NOx, and PM2.5 

respectively. Emissions benefits are initially small as the first compliant vehicles are 

sold into the California fleet. As time passes and more vehicles are sold, emission 

benefits increase. Emission benefits are fully realized in the 2035-2040 timeframe when 

nearly all vehicles operating in the fleet are expected to be compliant with the proposed 

Advanced Clean Cars standards. 

By 2035 ROG emissions would be reduced by an additional 34 percent and NOx 

emissions by an additional 37 percent, compared to 2035 without the proposed 

Advanced Clean Cars rules. Under the proposed rule, the new PM2.5 standard is 

reduced to 3 mg/mi in 2020 and 1 mg/mi in 2028. With these standards, the net PM2.5 

emissions will be essentially unchanged between 2010 and 2040 as growth in vehicle 

miles traveled offsets the tightening of the standard. It should be noted that the overall

PM emissions from light duty vehicles are a very small fraction of the overall California 

PM inventory. 
Page 177

Table V-D-2. Statewide and Regional Emission Benefits of the Advanced Clean Cars

Program (ROG)

Calendar

Year

Adjusted 

Baseline with 

Rebound

Proposed 

Regulation 

with 

Rebound

Benefits Percent 

Reduction

Statewide ROG (tons/day)

2023 189.6 182.9 6.6 3%

2025 175.5 164.4 11.1 6%

2035 141.1 93.6 47.4 34%

South Coast Air Basin ROG (tons/day)

2023 72.9 70.3 2.6 4%

2025 68.9 64.7 4.2 6%

2035 56.9 41.0 16.0 28%

San Joaquin Valley Air Basin ROG (tons/day)

2023 22.4 21.7 0.7 3%

2025 21.6 20.4 1.2 5%

2035 20.2 15.3 4.9 24%

Table V-D-3. Statewide and Regional Emissions Benefits of the Advanced Clean Cars

Program: NOx

Calendar

Year

Adjusted 

Baseline with 

Rebound

Proposed 

Regulation 

with 

Rebound

Benefits Percent 

Reduction

Statewide NOx (tons/day)

2023 201.3 185.6 15.7 8%

2025 183.6 161.2 22.4 12%

2035 136.8 86.4 50.4 37%

South Coast Air Basin NOx (tons/day)

2023 92.5 86.4 6.1 7%

2025 85.0 76.4 8.7 10%

2035 63.8 45.1 18.7 29%

San Joaquin Valley Air Basin NOx (tons/day)

2023 31.3 29.2 2.1 7%

2025 29.0 25.9 3.1 11%

2035 23.3 16.2 7.1 30%
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Table V-D-4. Statewide and Regional Emissions Benefits of the Advanced Clean Cars

Program: PM2.5

Calendar

Year

Adjusted 

Baseline with 

Rebound

Proposed 

Regulation 

with 

Rebound

Benefits Percent 

Reduction

Statewide PM2.5 (tons/day)

2023 26.7 26.0 0.6 2%

2025 27.2 26.3 0.9 3%

2035 29.7 26.8 2.9 10%

South Coast Air Basin PM2.5 (tons/day)

2023 10.5 10.3 0.2 2%

2025 10.7 10.3 0.3 3%

2035 11.3 10.2 1.0 9%

San Joaquin Valley Air Basin PM2.5 (tons/day)

2023 3.0 2.9 0.1 2%

2025 3.1 3.0 0.1 3%

2035 3.7 3.4 0.3 9%

E. FUEL CYCLE EMISSIONS

As projected by staff, compliance with ZEV and LEV III regulations will involve 

increased deployment of advanced technologies, some of which will involve alternative 

fuels that result in some emissions at sources associated with fueling the vehicle fleet, 

but that are outside the direct purview of the regulation. While such “upstream” 

emissions are still generally less than those associated with conventional gasoline use, 

a full emissions analysis accounts for them. As described in section III.A.5, the design 

of the LEV III GHG standards directly integrates the relative upstream GHG impacts of 

electricity- and hydrogen-powered vehicles compared to conventional petroleum 

combustion vehicles. Those regulatory provisions would mitigate the risk of unintended 

GHG emission increases upstream that would otherwise undermine the program GHG 

goals due to the increased deployment of ZEV-type vehicles. This section provides 

additional analysis exclusively on technologies’ upstream fuel-cycle and vehicle 

manufacturing-cycle impacts for GHGs and criteria pollutants.

This section summarizes additional staff life-cycle analysis, with greater detail on the 

upstream GHG emissions and local criteria pollutants from the various vehicle 

technologies that are likely to be deployed for compliance with the standards. Beyond 

the various vehicles’ direct tailpipe emissions, staff considers the lifecycle emissions 

that are inherent to the delivery of gasoline, electricity, and hydrogen to vehicles. Staff 

notes that there is the potential that other alternative fuel vehicles (e.g., vehicles that 

utilize diesel fuel and compressed natural gas) could be utilized to contribute toward 

compliance with the proposed LEV III-GHG-plus-ZEV regulatory compliance. However, 

staff focuses this assessment of the lifecycle emission impacts on the same primary 

technical compliance scenario considered above for regulatory compliance with 
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advanced gasoline, electric, and hydrogen fuel cell technologies. Also included in this 

analysis are the potential upstream impacts from vehicle production-cycle effects and 

the rebound effect of increased vehicle travel. 

As part of California’s Low Carbon Fuel Standard (LCFS), ARB staff has extensively 

researched the lifecycle impacts of transportation fuels. As part of the LCFS, ARB 

developed the CA-GREET lifecycle emission modeling tool (CARB, 2009a). The CAGREET tool was developed from the state-of-the-art Argonne National Laboratory 

model that is used by researchers around the world, but the model was subsequently 

adapted for the particular emissions characteristics of California. From the CA-GREET 

tool, upstream pollutant emission factors have been extracted for this analysis in order 

to ensure consistent emissions assumptions across ARB’s interrelated vehicle and fuel 

programs. This section investigates the associated upstream emission impacts of the 

“no new policy” and the proposed LEV III-GHG plus ZEV 2025 scenarios, with the use 

of emissions estimations from the CA-GREET model. 

As analyzed above and illustrated in Figure V-E-1, staff’s analysis projects that the 

California light-duty vehicle fleet will move from nearly all gasoline-fueled vehicles 

(including gas-electric hybrids) in 2010 to approximately 15% of new 2025 vehicles that 

can be powered by electricity or hydrogen (including BEVs, PHEVs, and FCVs); as 

such, these technologies are included here in this upstream analysis of the LEV/ZEVcompliant new vehicle fleet. This ARB staff proposal would modify existing regulations 

for GHG emissions, oxides of nitrogen (NOx), hydrocarbons (specifically NMHC), and 

particulate matter (PM); therefore, these are the pollutants that are examined. This 

analysis looks at these vehicles from an overall fleet perspective, including the new 

2017-2025 vehicles gradually displacing older, retiring vehicles in the fleet.
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Figure V-E-1. Projected technology mix for new vehicle fleet in compliance with 

proposed LEV and ZEV regulations

The primary step in this analysis involves the estimation of upstream emission factors 

associated with each unit of fuel (i.e., gasoline, electricity, hydrogen) production. Those 

upstream fuel-related emission factors, which include processes of extracting, refining, 

and transporting the final fuel or energy carrier, are shown in Table V-E-1. The 

California GREET model offers estimations on urban versus non-urban emissions to 

help differentiate where those emissions occur (e.g., mining facilities away from 

population centers, versus plants and transportation effects that are within urban areas). 

However, staff notes that there is significant uncertainty about the extent to which the 

emissions are likely to occur in California or elsewhere, although they are all 

conservatively included in this assessment. 

Table V-E-1. Fuel-related upstream (well-to-pump) emission factors assumed, 2020-2025 

fuel production pathways in California

Emission California reformulated 

gasoline (g/gallon)

Electricity 

(g/kWh)

Hydrogen 

(g/kg H2)

Total VOC 2.82 0.02 1.42

NOx 2.46 0.09 7.16

PM2.5 0.29 0.02 1.74

GHG 2655 270 9132

Urban VOC 2.18 0.01 0.09

NOx 0.20 0.03 0.91

PM2.5 0.005 0.005 0.367

Non-urban VOC 0.63 0.01 1.33

NOx 2.26 0.06 6.25

PM2.5 0.29 0.01 1.37

Emission factors assumed for 2020-2025, based on CA-GREET1.8b, EEE, 2010b
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Staff notes several assumptions regarding its consideration here of future electricity 

energy sources. Although above in section III.A.5 the compliance standards for GHG 

emissions were based on average GHG emissions from an RPS-compliant power 

sector (from EEE, 2010a), this analysis assumes a more conservative (i.e., worst case, 

higher-emission) scenario for marginal criteria pollutant emissions from power plants. In 

this analysis of upstream criteria pollutant emissions, electric vehicles are all assumed

to be charged from a mix of marginal power plant power sources of 67% natural gas 

power plants and 33% renewable (therefore not utilizing base-load large hydroelectric, 

nuclear, or coal plants). The various upstream criteria pollutant emission factors, 

transmission and distribution line losses, and energy production and extraction 

emissions are all based on CA-GREET modeling.

A number of assumptions were made for this analysis, along with the use of California 

GREET upstream criteria pollutant emission factors. Staff notes a number of caveats 

related to the relative lack of certainty on future California upstream emission factors. 

First, staff utilizes the “total” emissions as shown in the above table, whereas, the 

“urban” emissions may be more relevant from an inventory and public health 

perspective. Second, the upstream emission effects are conservatively assumed to be 

in California, whereas some emission impacts are in distant primary energy extraction 

operations around the world. 

As a result of this analysis, staff recommends that the California GREET model be 

updated over time to include improved upstream emission factors for non-GHG 

pollutants that better reflect new projected hydrogen and electricity developments, as 

well as differentiation of whether emissions are in-state or not. At present, ARB staff 

has made simple, conservative assumptions for these emission factors, assuming they 

occur in California.

In addition to the fuel cycle emission factors, the manufacturing cycle emissions are 

examined. As described above the literature on vehicle manufacturing cycle GHG 

emissions is varied, but it suggests that incremental near-term mass reductions (up to 

10-15% mass reduction) could result in no net changes upstream emission reductions; 

however, advanced electric drive technologies appear to be associated with greater 

upstream emissions than gasoline vehicles (Kim et al, 2010; Patterson et al, 2011; ANL, 

2007). Table V-E-2 shows the assumed vehicle manufacturing-cycle emission factors 

used in this assessment. With the average 2020-2025 new gasoline vehicle having an 

8-9% mass reduction (as above, for the compliance scenario analysis), these advanced 

gasoline vehicles are expected to have marginally lower manufacturing-related 

emissions; however, ZEV-type vehicles are expected to have higher manufacturingcycle emissions. ARB staff acknowledges high uncertainty in the data for 

manufacturing GHG emissions, and even scarcer data on the local air pollutants 

associated with manufacturing various vehicle technologies. As a result, several 

simplifying assumptions were used (e.g., EVs were assumed to have the same 

upstream manufacturing criteria pollutant emissions as HEVs, due to lack of data).
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Table V-E-2. Vehicle production-cycle emission factors assumed (gram/vehicle)

Gasoline baseline Gasoline LEV III

(2017-2025) Electric vehicle Fuel cell vehicle

GHG 6,850,104 6,031,041 11,019,731 9,771,084

VOC/HC 1,658 1,573 1,620 1,710

NO x 6,808 6,363 7,262 10,303

PM2.5 4,481 4,154 4,668 5,187

Based on GREET 2.7 (ANL, 2007); Kim et al, 2010; Patterson et al, 2011

Figures V-E-2 and V-E-3 show NOx and hydrocarbon (HC) emission upstream emission 

effects from the various processes on a ton per year basis in calendar year 2030. To 

emphasize, these figures are showing only upstream emissions (i.e., excluding tailpipe 

exhaust emissions). For hydrocarbons, volatile organic compound (VOC) emissions are 

tracked in GREET and are shown in the figure, whereas the similar regulated 

hydrocarbon pollutant in LEV III is NMOG. The vehicle manufacturing production-cycle 

upstream emissions are also included, as assessed in the section above, related to the 

use of advanced materials, EV, and FCV technologies. The figures for NOx and HC 

both show similar results. From baseline 2030 upstream emissions, there are small 

increases in emissions due to vehicle manufacturing, electricity generation, and 

hydrogen production from the proposed LEV III and ZEV program. However, the 

reduced petroleum upstream emissions fully offset the increases from manufacturing 

and fuel production factors for both NOx and HC emissions. As illustrated in the figures, 

the changes in upstream emissions are -11% for NOx and -17% for HC from their 

baseline upstream emission levels from the fuel and vehicle production cycles. 

Figure V-E-2. Potential impact on upstream NOx emissions from vehicle and fuel 

production
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Figure V-E-3. Potential impact on upstream hydrocarbon emissions from vehicle and 

fuel production

Figure V-E-4 shows the upstream PM effects (i.e., excluding tailpipe emissions) of the 

different factors in calendar year 2030. The impact of the upstream effects of the 

vehicle manufacturing production-cycle and fuel production processes is found to be 

relatively small, with a net impact of -4%. The same as for the NOx and HC cases 

above, the largest upstream effect is the reduced upstream gasoline production PM 

emissions. 

Figure V-E-4. Potential impact on upstream PM emissions from vehicle and fuel 

production in 2030

The upstream GHG emission impacts in 2030 are shown in Figure V-E-5. As was 

evaluated and described in the LEV III GHG compliance analysis, the GHG standards 

are designed to directly integrate the relative GHG impact of electric and hydrogen 

vehicles (versus gasoline vehicles) through straightforward provisions. This analysis in 

Figure V-E-5 isolates only the upstream GHG effects for the fleet in calendar year 2030. 
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The overall result is that the upstream GHG emission reductions from lower petroleum 

throughput are greater than the increases from vehicle manufacturing and electricity 

and hydrogen production. When just analyzing these effects that are upstream from the 

vehicles, the GHG emissions show an 8% GHG reduction. Staff emphasizes that the 

fuel-cycle GHG emissions from electricity and hydrogen production would be accounted 

for in the California-specific upstream compliance accounting (but would not under the 

proposed federal upstream 0 g/mi incentive provisions).

Figure V-E-5. Potential impact on upstream GHG emissions from vehicle and fuel 

production in 2030

Based on this analysis, staff finds that the regulated pollutants will have relatively small 

emission impacts upstream from the regulated vehicles. The upstream emission 

impacts are small but would result in greater emission reduction benefits than would be 

projected when just analyzing the vehicles. This is the result of the emission benefits of 

reduced petroleum upstream emissions for GHG, HC, NOx, and PM outweighing the 

smaller cumulative emission increases from the vehicle manufacturing, electricity 

generation, and hydrogen production emissions from advanced vehicle technologies 

that are projected to be deployed for compliance with the proposed regulation. 

Table V-E-3 summarizes the results for upstream NOx, HC, and PM emission impacts. 

The analysis indicates that, in calendar year 2030, the net upstream benefits are about 

31 tons/day in combined NOx+HC reductions and about 1 ton/day of PM reduction. 

These upstream benefits would be in addition to those that are accounted for in the 

EMFAC inventory analysis above that evaluates the direct emissions from vehicle 

operation. The table reflects, as above, how the potential upstream benefits from the 

reduction in petroleum consumption more than outweigh the potential for increased 

manufacturing and fuel-cycle emissions from the advanced vehicle technologies that will 

be promoted from the proposed regulation. In addition, as discussed in the 

Environmental Assessment (Attachment B), these net upstream benefits would offset 

any emissions increase due to any unlikely delay in fleet turnover, which is not projected 

at this time.
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Table V-E-3. Year 2030 upstream emission impacts from LEV III-GHG-ZEV scenario

Emission

Upstream emissions 

with no new policy 

(tons/day)

Effect of LEV III-GHG-ZEV 

regulatory package on upstream 

emissions (tons/day)

Upstream 

emission 

change

NOx 116.7 -13.2 -11%

HC 105.0 -17.9 -17%

PM 30.4 -1.1 -4%

These upstream emission benefits have been estimated here, outside of the EMFAC 

modeling in section V.D, due to the more uncertain assumptions for the upstream 

emission factors as outline in this section. Staff believes these upstream benefits and 

their underlying data basis should be studied again as more advanced vehicle 

technologies enter the fleet and their upstream effects become more definitively known.

For context, staff compares this section’s findings for the upstream emission effects with 

on-road vehicle emission modeling from EMFAC. The upstream emission impacts tend 

to be considerably less than the on-road emissions overall, and the small upstream 

emission benefits found in this section would generally be an order of magnitude lower 

than the LEV III and ZEV vehicle programs’ overall NOx, HC, and PM emission levels. 

For example, the light-duty vehicle NOx+HC emissions at the vehicle in calendar year 

2030 from the proposed regulations were 242 tons/day, whereas the NOx+HC net 

upstream emission reductions were about 31 tons/day. As a result, these upstream 

benefits would amount to an approximate 13% reduction from the total NOx+HC 

emissions from light-duty vehicle activity in 2030. The PM net reductions of 1 tons/day 

in 2030 from this upstream analysis would be smaller, amounting to about a 4% 

reduction from the total light-duty vehicle PM emissions from the EMFAC modeling. 

 

F. HEALTH BENEFITS ASSOCIATED WITH REDUCTIONS IN PM AND NOx 

EMISSIONS FROM PASSENGER VEHICLES RESULTING FROM 

IMPLEMENTATION OF THE LEV III AND ZEV PROGRAMS

1. OVERVIEW

Staff estimates that, statewide, implementation of the Low-Emission Vehicle (LEV III) 

and Zero-Emission Vehicle (ZEV) programs over the period from 2010 through 2025 will 

eliminate approximately 1,400 tons of PM2.5 and 40,000 tons of NOX emissions from 

passenger vehicles. The estimate of the reduction of premature deaths associated with 

these emission reductions for both primary PM and secondary PM (produced in the 

atmosphere from the precursor NOX) are presented in Table V-F-1.
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Table V-F-1. Estimate of Premature Deaths from Cardiopulmonary Causes Avoided 

Associated with Emission Reductions from Implementation of the LEV III and ZEV

Programs (2010-2025)*

Regulation Pollutant

Avoided Premature Deaths from Cardiopulmonary 

Causes

Lower Bound

(95% C.I.) Mean Upper Bound (95% C.I.)

LEV III and 

ZEV

PM2.5 140 180 230

NOX 190 250 300

Total 330 430 530

* Health effects from primary and secondary PM are labeled PM2.5 and NOX, 

respectively.

This estimate of premature deaths avoided is based on a peer-reviewed methodology 

used by the U.S. Environmental Protection Agency (USEPA, 2010). The methodology is

fully described in ARB (2010) and is only briefly summarized in the sections below.

2. PREMATURE DEATH ESTIMATION METHODOLOGY

2.1. Overview

The incidents-per-ton (IPT) methodology is used to quantify the health benefits of 

directly emitted (primary) and secondary PM2.5 reductions due to regulatory controls. It 

is similar in concept to the methodology developed by the USEPA for similar 

estimations (Fann et al., 2009). The basis of the IPT methodology is the approximately 

linear relationship which holds between changes in emissions and estimated changes in 

health outcomes. 

In this methodology, the number of premature deaths is estimated by multiplying 

emissions by a scaling factor, the IPT factor. The IPT factor is derived by calculating the 

number of premature deaths associated with exposure to PM2.5 from a specific source, 

using the C-R function described below, and dividing by the emissions of that PM2.5 

source.

The IPT factors used for primary PM2.5 in this assessment were originally developed 

for use with diesel PM emissions, rather than emissions from the (non-diesel) 

passenger vehicles for which LEV III and ZEV are being proposed. However, applying 

diesel IPT factors to non-diesel vehicle PM emissions is justified on the grounds that 

emission patterns, dispersion mechanisms and loss mechanisms of primary PM from all 

on-road vehicular sources are expected to be similar. That is to say that a ton of PM 

emitted from on-road non-diesel vehicles are expected to result in the same PM2.5 

exposure and health effects as a ton of emitted PM from on-road diesel trucks.
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In addition to directly emitted, primary PM, motor vehicle exhaust contains NOX, which 

is a precursor to nitrates, secondary PM nitrates formed in the atmosphere that can lead 

to an additional impact on premature death beyond those associated with directly 

emitted PM2.5. For secondary PM, staff calculated the health impacts resulting from 

the three-year average exposure to these concentrations of PM-nitrate and then

associated the impacts with the basin-specific NOX emissions to develop basin-specific 

factors (IPT). The basin-specific factors and emissions were applied to each air basin 

to estimate health benefits.

2.2. Concentration-Response Function

Calculation of the change in premature deaths associated with changes in PM2.5 

exposure requires a C-R function, population data, baseline death rates, and the 

change in concentration of PM2.5. These data are available in a spreadsheet as part of 

the rulemaking package. Calculations were made based on both primary and secondary 

PM2.5 exposure. The sources and derivation of these parameters are described below.

The equation is: 

Where:

ΔY = Change in number of premature deaths associated with change in PM2.5 

concentration;

yo = Baseline all-cause death rate for age 30 and above (CDPH);

β = Beta coefficient derived from the relative risk of epidemiologic study;

ΔPM = Change in PM2.5 concentration; and

Pop = Population age 30 or above (US Census Bureau).

The spatial resolution of the underlying data is at the census tract-level with the 

exception of the baseline death rate, which is at the county level. Estimates of 

premature deaths are calculated at each census tract in California, and aggregated to 

county, air basin and statewide levels.

The C-R function relates changes in PM2.5 (ΔPM) exposure to changes in premature 

death (ΔY). The amount of change is characterized by the coefficient Beta (β). It is 

derived from the relative risk of deaths associated with changes in annual average 

PM2.5 concentration published in epidemiological studies. In this case, we are using 

Krewski et al. (2009), as described by USEPA (2010). 

The C-R function is applied as the percent change in the all-cause death rate (yo) per 

10 μg/m3 change in PM2.5. We use death rates by county for 7 age brackets (30-34, 

35-44, 45-54, 55-64, 65-74, 75-84, 85+).

We assumed that the C-R function was linear down to a concentration of 5.7 

μg/m3 because Krewski et al. (2009) examined exposures at 5.7 μg/m3 and above. No 

premature deaths were estimated in census tracts where the annual average of PM2.5 

was below this threshold.
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2.3. Estimating Population at the Census Tract Level

Age-resolved population data at the census tract level, for the 2000 Census, were 

obtained from the U.S. Census Bureau (U.S. Census Bureau). These were projected to 

2006-2008 using age-resolved county population projections from the California 

Department of Finance (CDOF).

Age-specific population growth factors for each county, for each year, were computed 

from the CDOF projections by dividing each county population for the target year by the 

county population for the year 2000. Since each census tract lies entirely in a county, 

these growth factors were applied to each census tract in the county, for each age 

group separately. Population was projected for ten-year age groups 25-34 through 75-

84, and for age 85 and older.

This method of projection reflects growth in overall county population, but does not 

model changes in population distribution within counties, such as expansion of urban 

areas into surrounding rural land.

2.4. Baseline Cardiopulmonary Death Rate

Baseline death rates (yo) were used to calculate the estimates presented in this report. 

There is uncertainty in these baseline rates. Often, one must assume a baseline death 

rate level to be consistent throughout the city or county of interest. In addition, death 

rate can change over time as lifestyles, income and other factors evolve. For this 

analysis, we used the same baseline rates that the USEPA used. Additional information 

was obtained from the California Department of Health Services and the Centers for 

Disease Control and Prevention. 

Baseline death rates vary by age bracket. Death rates were estimated separately for 

ten-year age groups 25-34 through 75-84, and age 85 and older. Baseline 

cardiopulmonary death rates were estimated at the county level from individual death 

records for the year 2005, obtained from the California Department of Public Health 

(CDPH). Cardiopulmonary death was defined as ICD9 codes 161-187 and 192-214.

The county of residence of the decedent is generally not recorded in California. 

However, the Federal Information Processing Standards (FIPS) city code and the ZIP 

code were usually recorded. The FIPS city code unambiguously identifies the county, 

but was sometimes invalid, unrecorded, or recorded as “unknown”. When the FIPS 

code was not available it was sometimes possible to identify the county from the ZIP 

code, but ZIP codes can overlap multiple counties. In cases where 90% or more of the 

area of the decedent’s zip code lay entirely within a county, the death was assigned to 

that county. A handful of records included invalid dates. The breakdown of records 

was as follows:

County identified by FIPS code 231,181 96.6%

County identified by ZIP code 4,196 1.8%
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Unidentified or invalid 3,851 1.6%

Because the county could not be determined for 1.6% of the records, the number of 

deaths is slightly underestimated. No adjustment was made to compensate for excluded 

records.

In some cases the cardiopulmonary death incidence was extremely low, because some 

counties have a population of only a few thousand, and the population is further 

subdivided into age groups. In such cases the variability of the incidence is high. 

However, since this represents a very small fraction of California’s population the effect 

on statewide death estimates is negligible. Large counties show little year-to-year 

variability.

Baseline death rates are subject to other sources of uncertainty. For example, the 

baseline death rate is treated as uniform throughout the county of interest even though 

it is possible that the death rate varies within a county. In addition, baseline death rates 

can change over time as lifestyles, health care, income, and other factors evolve.

2.5. Estimating Exposure to PM2.5

As described above, the IPT factors used for primary PM2.5 for this assessment were 

originally developed for use with diesel PM emissions. Thus, the value for exposure to 

diesel PM2.5 was applied to the C-R function to estimate the health impact. Staff 

estimated exposure to the primary diesel PM using monitored NOX concentration as a 

surrogate, as described previously (CARB 2010). To quantify impacts from secondary 

PM, staff developed population-weighted PM nitrate concentrations for each air basin 

using data from the statewide routine monitoring network for years 2006, 2007 and 

2008.

In this assessment, population-weighed exposure to primary and secondary PM2.5 was 

estimated based on monitor-specific concentrations. Even with an extensive air quality 

monitoring network, the death quantification method requires estimation of exposure 

between monitors across a geographic area. ARB uses a standard spatial interpolation 

method known as inverse distance-squared weighting (Shepard, 1968; Goodin et al., 

1979). This method yields reasonable accuracy in estimating pollutant concentrations 

near monitoring stations, although as distance from the monitoring station increases, 

the uncertainty in the PM2.5 concentration also increases. This method gives accurate 

estimates of concentration in areas with a large number of monitors with good spatial 

coverage and low variability in concentration. When data are sparse, however, the 

assumption made about the underlying variation in PM2.5 concentration, along with the 

choice of interpolation method and its parameters, can be critical to avoid misleading 

results.

To aggregate results from census tracts to larger geographical subdivisions such as 

counties or air basins, we used a GIS technique called areal interpolation. Areal 

interpolation is a procedure for translating spatial data from one set of geographical 
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subdivisions to another when the boundaries do not exactly overlap. Numerous 

variants of the technique exist, but for the purpose of this analysis the simplest form, 

which uses area of polygon intersection, was employed (Goodchild and Lam, 1980; 

Fotheringham and Rogerson, 1994).

The precision of areal interpolation based on area of intersection depends on the 

relative size of the geographical subdivisions, and the homogeneity of the spatial 

distribution of the quantity being apportioned. In urban areas, where census tracts are 

small and population is distributed more evenly, areal interpolation to larger subdivisions 

such as air basins yields relatively precise estimates. In rural areas where the 

population is distributed unevenly over large census tracts, estimates are less precise.

VI. ENVIRONMENTAL IMPACTS ANALYSIS

ARB is the lead agency for the proposed regulation and has prepared an environmental 

analysis pursuant to its certified regulatory program. The California Environmental 

Quality Act (CEQA) at Public Resources Code section 21080.5 allows public agencies 

with regulatory programs to prepare a plan or other written document in lieu of an 

environmental impact report or negative declaration once the Secretary of the 

Resources Agency has certified the regulatory program. ARB’s regulatory program has 

been certified by the Secretary of the Resources Agency.37 As required by ARB’s 

certified regulatory program for the proposed regulations, the environmental analysis is 

included in the Staff Report: Initial Statement of Reasons (ISOR) for the rulemaking. 38

Appendix B to the Staff Report is an Environmental Analysis that provides an evaluation 

of the potential for environmental impacts associated with the proposed Advanced 

Clean Cars Program. The proposed Advanced Clean Cars Program consists of 

amendments to the following regulations: Low-Emission Vehicle (LEV III), the E10 

Certification Fuel, Environmental Performance Label, On-Board Diagnostics, ZeroEmission Vehicle (ZEV), and the Clean Fuels Outlet. Three separate Regulatory 

Notices and Staff Reports have been prepared for these proposed amendments. A 

single coordinated analysis of the potential environmental impacts is analyzed in 

Appendix B. The Environmental Analysis assesses the potential for significant long or 

short term adverse environmental impacts associated with the proposed actions and an 

analysis of those impacts.39 In accordance with ARB’s regulations, the Environmental 

Analysis also describes any beneficial impacts.40 The resource areas from the state 

CEQA Guidelines environmental checklist were used as a framework for assessing 

potentially significant impacts.41 

If comments that are received during the public review period raise significant 

environmental issues, staff will summarize and respond to the comments in writing. The 

written responses will be included in the Final Statement of Reasons for the regulation. 

 37 State CEQA Guidelines section 15251 (d); CCR, title 17, sections 60005-60008.) 38 CCR section 60005. 39 CCR section 60005, subd (b). 40 CCR 60005, subd. (d). 41 State CEQA Guidelines, Appendix G.
Page 191

In accordance with ARB certified regulatory program, prior to taking final action on the 

proposed regulation, the decision maker will approve the written responses.42 If the 

regulation is adopted, a Notice of Decision will be posted on ARB’s website and filed 

with the Secretary of the Natural Resources Agency for public inspection.43

VII. ECONOMIC IMPACTS

The climate change regulation may impact several sectors of the economy. The steps 

that manufacturers will need to take to comply with the regulatory standards are 

expected to lead to price increases for new vehicles. Many of the technological options 

that manufacturers choose to comply with the greenhouse gas portion of the regulation 

are also expected to reduce operating costs. These two responses to the regulation 

have combined positive and negative impacts on California businesses and consumers. 

The vehicle price increase will be borne by purchasers and may negatively affect 

businesses. However, the operating cost savings from the use of vehicles that comply 

with the greenhouse gas regulation will positively impact consumers and most 

businesses. Based on the staff analysis, the net effect of the regulation on the economy 

is expected to be small but positive. 

The major tool used for the analysis of the economic impact of the proposed regulation 

is a model of the California economy developed by the University of California, 

Berkeley, named the Environmental Dynamic Revenue Analysis Model (E-DRAM). This 

chapter explains the legal requirements for economic analysis, the methodologies 

employed, and the results obtained. Appendix S to this report further explains the 

economic impact analyses.

A. LEGAL REQUIREMENTS

The legal requirements for economic analysis are included in the Government Code and 

the Health and Safety Code. This section summarizes the requirements that must be 

satisfied for economic analyses of the proposed regulations.

Section 11346.3 of the Government Code, which applies to all agencies statewide, 

requires State agencies to assess the potential adverse economic impacts on California 

business enterprises and individuals when such agencies propose to adopt or amend 

any administrative regulation. The assessment shall include a consideration of the 

impact of the proposed regulation on California jobs, business expansion, elimination or 

creation, and the ability of California business to compete with businesses in other 

states. Additionally, climate change legislation such as AB1493 and AB32 also require 

greenhouse gas reduction regulations to consider the potential impacts on minority and 

low-income communities.

State agencies also are required to estimate the cost or savings to any State or local 

agency and school district, in accordance with instructions adopted by the Department 

 42 CCR 60007, subd (a). 43 CCR 60007, subd. (b).
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of Finance (DOF). The estimate shall include any non-discretionary cost or savings to 

local agencies and the cost or savings in federal funding to the State.

Finally, Health and Safety Code section 57005 requires the Air Resources Board to 

perform an economic impact analysis of submitted alternatives to a proposed regulation 

before adopting any major regulation. A major regulation is defined as a regulation that 

will have a potential cost to California business enterprises in an amount exceeding ten 

million dollars in any single year. Because the proposal is a major regulation, we have 

performed an economic impact analysis, which is presented in the subsequent section. 

B. SUMMARY OF COMPLIANCE COST ESTIMATES

The proposed amendments would require a combination of technologies in different 

vehicle classes to comply with both the criteria and greenhouse gas standards. 

Compliance costs will vary according to the type of emission standard, which in turn 

varies according to the vehicle class. As shown in Table VII-B-1, not all vehicles are 

subject to all aspects of the proposed amendments. Our primary analysis evaluates the 

combined effects of all proposed amendments.

Table VII-B-1. Summary of Vehicles Subject to Proposed Amendments

Criteria Pollutant 

Standards

Greenhouse Gas 

Standards

ZEV 

Amendments

Light-duty Vehicles Yes Yes Yes

Medium-duty 

Vehicles Yes

Only those 

primarily used for 

passenger travel

No

As discussed previously, the new light-duty criteria pollutant standards phase in 

beginning with MY2015 while more stringent greenhouse gas standards do not begin 

until MY2017 vehicles and amendments to the ZEV program would not take effect until 

MY2018. Thus, the proposed near term (MY2015-2016) regulations would increase the 

average retail prices of light-duty vehicles by $5 to $14 per vehicle to comply with the 

proposed criteria pollutant standards.44 In the mid-term (MY2017-2021) vehicle prices 

would increase as a result of both standards for light-duty vehicles as well as the 

increasing share of ZEVs required. Relative to the baseline, increases for light-duty 

vehicles would range from $180 to $1290 per vehicle. In the long term (MY2022-2025), 

the price increases for light-duty vehicles relative to the baseline would range from 

$1,530 to $1,910. Note that these costs do not include any state or federal financial 

incentives currently or expected to be offered on the purchase of new alternative fuel 

vehicles.

The majority of MDVs would only be subject to the criteria pollutant standards during the 

regulatory period. Their vehicle price increases are assumed to be fixed at $82 per 

 44 Note all costs are presented in year 2009 dollars. 
Page 193

vehicle between MY2016 and MY2025. In the earlier model years, the near-term costs,

while the standard is still phasing in, would likely be lower; however due to their 

relatively low volumes this simplifying assumption has a negligible (but conservative) 

effect on the total compliance costs. A one-time cost of $300,000 in MY2016 is also 

attributed to the certification costs for medium-duty SFTP compliance (See Appendix P). 

The incremental retail prices of the new emission-reduction technology for all affected 

vehicles are assumed to fall at an annual rate of 2% after MY2025 once the standard is 

fully phased in.

 

These incremental technology costs from the regulation are analyzed assuming 

manufacturers operate in a perfectly competitive market and pass them on to 

consumers in full. This section annualizes these costs and estimates the corresponding 

operating cost savings for an analysis of impacts on the California economy. The net 

impact of vehicle price increases on consumers is discussed later in this section. The 

new light-duty vehicles have median lifetimes of 14-17 years, over which time they will 

provide lower operating costs. To match the costs to the years of benefits, the 

incremental vehicle costs are annualized over the life of the vehicles. Few medium-duty 

vehicles would experience any operating cost reductions from these regulations so only 

net costs are annualized over their median life of 20 years for inclusion in the total cost 

estimates.45 Annualized incremental costs are estimated using a real discount rate of 

five percent based on an average of the past ten-year interest rates for new vehicle 

loans. 

There are no expected increases in costs associated with producing the proposed E10 

certification fuel. In general, staff tried to keep the width of the property ranges for each 

specification the same spread of the property ranges in the current certification fuel. 

Only sulfur and end point have different specification spreads. The spread for sulfur 

decreased from a width of 10 ppmw to a width of 3 ppmw. End point went from being a 

maximum of 390 degrees F to a range for 380-420 degrees F. Staff consulted with 

specialty fuel manufacturers to see if the changes in these two properties would cause 

any difficulties in producing the fuel. Based on input received from the specialty fuel 

manufacturers, staff determined that the width of the property ranges for sulfur and end 

point did not cause any difficulties in producing the proposed certification fuel. Since 

there are no expected incremental production costs for the proposed E10 certification 

fuel, staff does not expect any costs to small business or consumers and therefore no 

additional costs for compliance with this portion of the amendments are included in the 

economy-wide modeling.

Annualized Costs. Table VII-B-2 provides estimates of annualized costs of the 

proposed Advanced Clean Cars program from 2015 to 2030. The total cost was 

derived by multiplying new vehicle sales by the average per vehicle price increase 

described above. The new vehicle sales totals are based on the projected compliance 

scenario fitted to new vehicle registrations estimates forecast by EMFAC2011. The 

 45 Note, while these proposed amendments do not directly result in operating cost savings, concurrent federal 

regulations improving fuel economy of medium-duty vehicles will likely result in substantial savings that would offset 

these compliance costs. However, we do not include these savings in this analysis.
Page 194

total costs to consumers vary each year from 2015 to 2030. Annualized costs of the 

proposed regulations are estimated to be approximately $390 million in 2020, $1.8 

billion in 2025, and $3.4 billion in 2030. The annualized cost increases over time, due 

to additional sales of new cars at the higher price as multiple model years are 

annualized over the same period. For example, the annualized cost in 2020 of $390 

million reflects the annualized costs of model years 2015 through 2020. Thus, the 

annualized costs for each calendar year are for cumulative sales of new cars since 

2015. The $1.8 billion in annualized cost in 2025 represents the cost, in 2025, of all 

complying vehicles sold from 2015 through 2025. 

Table VII-B-2. Estimates of Total Annualized Incremental Costs of the Proposed 

Advanced Clean Cars Program for 2015 through 2030 (millions of 2009 Dollars)

Year

Annualized 

GHG Costs 

to PC 

Consumers

Annualized 

GHG Costs 

to LDT 

Consumers

Annualized 

Criteria 

Pollutant

Costs to LDV 

Consumers

Annualized 

Criteria 

pollutant

Costs to 

MDV 

Consumers

Total 

Annualized 

Compliance 

Costs

Cumulative 

Annualized 

Incremental 

Cost

2015 $0 $0 $1 $0 $1 $1 

2016 $0 $0 $2 $0 $2 $4 

2017 $16 $9 $4 $0 $29 $33 

2018 $48 $15 $5 $0 $67 $100 

2019 $98 $20 $6 $0 $124 $225 

2020 $134 $25 $8 $0 $166 $392 

2021 $176 $32 $9 $0 $217 $609 

2022 $213 $36 $10 $0 $259 $868 

2023 $244 $40 $11 $0 $295 $1,163 

2024 $276 $44 $12 $0 $331 $1,495 

2025 $270 $49 $13 $1 $332 $1,827 

2026 $264 $49 $13 $0 $325 $2,153 

2027 $262 $48 $12 $0 $322 $2,475 

2028 $260 $48 $12 $0 $320 $2,796 

2029 $258 $48 $12 $0 $318 $3,114 

2030 $256 $47 $12 $0 $316 $3,430 

Note: Sum of individual columns may not match totals due to rounding.

Operating Cost Savings. Many of the technologies that reduce climate change 

emissions will also reduce the operating costs of light-duty vehicles. The change in 

criteria pollutant standards is not expected to change operating costs either positively or 

negatively. Lifetime maintenance costs are also expected to remain the same or 

decline, depending on the technologies chosen by manufacturers. For example, 

improved containment of air conditioning refrigerant may reduce the need for mobile air 

conditioning servicing and therefore reduce maintenance costs to consumers. Due to a 

lack of comprehensive data, however, staff assumed no change in maintenance costs 

for the purpose of this analysis. Estimates of the average reduction in fuelconsumption-related operating cost of the new vehicles range from about 4 percent for 

MY2017 vehicles to over 25 percent for MY2025 vehicles. Based on these expected 

operating cost reductions and the projected gasoline prices shown in Table VII-B-3, 

estimates of annual operating cost savings from 2015 through 2030 are provided in

Table VII-B-4. Additional details on these calculations are provided in Appendix S. As 
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shown for every dollar spent, the regulation could save consumers about $3. These 

savings include the expenditures on electricity and hydrogen associated with operating 

the greater volume of ZEVs being proposed. In cost-effectiveness terms, every ton of 

greenhouse gas reduction will produce a savings of $290 in 2025, which grows to $320

per ton of reduction in 2035. Although there are no savings associated with criteria 

pollutant emissions, as discussed in section II-A-4.3 the costs of those reductions on a 

per pound basis are quite low (see Table VII-B-5). In the absence of the proposed ZEV 

amendments the savings to cost ratio would be even greater. Figure VII-B-1 illustrates 

the savings-to-cost ratio in graphical form, where the difference between the two curves 

is shown as the shaded area. Overall, purchasers of new vehicles in 2015 and beyond 

would experience a significant reduction in their operating cost as a result of the 

proposed regulation. 

 

Table VII-B-3. Select Retail Gasoline Fuel Prices (2009 dollars per gallon)

Year Price

2011 $3.68

2015 $4.06

2020 $4.06

2025 $4.02

2030 $4.17

Source: Transportation Energy Forecasts and Analyses for the 2011 Integrated Energy Policy

Report, Draft Staff Report, California Energy Commission. Average of high and low cases, 

converted from 2010 dollars using Consumer Price Index adjustment factor.
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Table VII-B-4. Estimates of Total Annual Value of New Vehicle Operating Cost Savings

for Advanced Clean Cars (millions of 2009 Dollars)

Year

Cumulative 

Annualized 

Incremental 

Cost

Operating 

Cost 

Savings

Saving to 

Cost Ratio

2015 $1 $0 0.0

2016 $4 $0 0.0

2017 $33 $228 7.0

2018 $100 $487 4.9

2019 $225 $915 4.1

2020 $392 $1,438 3.7

2021 $609 $2,092 3.4

2022 $868 $2,918 3.4

2023 $1,163 $3,751 3.2

2024 $1,495 $4,671 3.1

2025 $1,827 $5,755 3.1

2026 $2,153 $6,846 3.2

2027 $2,475 $7,843 3.2

2028 $2,796 $8,803 3.1

2029 $3,114 $9,709 3.1

2030 $3,430 $10,630 3.1

Note: Operating cost savings account for increases in expenditures of electricity and 

hydrogen for fueling Zero-Emission Vehicles.

Table VII-B-5. Estimates of Cost Effectiveness for Advanced Clean Cars Reductions of 

Criteria Pollutants and Greenhouse Gases (2009 Dollars)

Year

PM2.5

($/pound 

reduction)

ROG+NOx 

($/pound 

reduction)

CO2e ($/ton 

reduction)

2025 $0 $4 $290 savings

2035 $0 $3 $320 savings
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Figure VII-B-1. Statewide Costs and Benefits of the Advanced Clean Cars Program (2009 

dollars)

C. POTENTIAL IMPACTS ON BUSINESS CREATION, ELIMINATION, OR

EXPANSION

The Advanced Clean Car regulation affects both light- and medium-duty vehicles for 

criteria pollutants; for greenhouse gas emissions, it only affects light-duty vehicles 

whose primary use is noncommercial personal transportation. Therefore, many of the 

medium-duty vehicles that businesses use would only be affected by the criteria 

pollutant portion of the proposed regulation, whose costs are expected to be minimal. 

However, if the businesses purchase the same light-duty vehicles as consumers, they 

would be expected to pay incrementally higher prices for the vehicles but save on 

operating costs, as is discussed in section VII.G Below. As noted in that section, staff 

expects that reduced operating costs will greatly outweigh the effect of the incremental 

vehicle price increase over the life of the vehicle.

$0

$2,000

$4,000

$6,000

$8,000

$10,000

$12,000

2009 dollars, Millions

Statewide Costs and Benefits of Advanced Clean 

Cars Program

Net Benefits

Total Annualized

Costs
Page 198

It is very likely that savings from reduced vehicle operating costs would end up as 

expenditures for other goods and services. These expenditures would flow through the 

economy, causing expansion or creation of new businesses in several sectors. Staff's 

economic analysis shows that as the expenditures occur, jobs and personal income 

would be positively impacted. Jobs would be unaffected in 2020, increase gradually by 

0.1 percent in 2025, and by 0.2 percent in 2030 compared to the baseline economy that 

excludes the proposed Advanced Clean Car regulatory package. Similarly, income 

grows by $1 billion in 2020, by $3 billion in 2025, and $6 billion 2030. Should only the 

LEV III (including GHG) amendments be adopted, the economic impacts would remain 

roughly unchanged. 

The E-DRAM model was used to assess the overall impact of the regulation on 

California’s economy. Specifically, E-DRAM was used to estimate impacts on 

California's output of goods and services, personal income, and employment. The 

estimates of the regulation's impact on these economic factors are used to assess the 

potential impacts on business creation, elimination, or expansion in California. The next 

section describes E-DRAM.

1. ENVIRONMENTAL-DYNAMIC REVENUE ANALYSIS MODEL (E-DRAM)

The overall impact of direct and indirect economic effects that may result from the 

proposed regulation are estimated using a computable general equilibrium (CGE) model 

of the California economy. A direct impact, as defined here, affects the automobile and 

oil industries, and their consumers. The proposed regulation may affect other economic 

sectors indirectly. For example, consumers are likely to redirect money from operating 

cost savings to spend on other sectors. In addition, the automobile industry would be 

expected to purchase goods and services from other sectors to comply with the

proposed regulation. These expenditures caused by the regulation would indirectly 

affect the California economy.

A CGE model simulates various economic relationships in a market economy, where 

prices and production adjust in response to changes caused by regulations to establish 

an equilibrium in markets for all goods and services and factors of production (i.e., labor 

and capital). The CGE model used for this analysis is a modified version of the 

California Department of Finance's Dynamic Revenue Analysis Model (DRAM). The 

DRAM has been used for several tax policy evaluations. The modified model accounts 

for environmental sectors and is called Environmental-DRAM (E-DRAM). It has been 

used to assess the economic impacts of California’s air quality State Implementation 

Plans, the AB32 Scoping Plan, reformulated gasoline regulations, vehicle greenhouse 

gas standards, and other regulations. A previous version of E-DRAM was peer 

reviewed as part of the Scoping Plan process and did not reveal any significant 

concerns. Additional details about E-DRAM can be found in Appendix S.

Economic Impacts: Higher vehicle prices provide a means to estimate the direct 

expenditures that will be incurred by California businesses, governments, and 

individuals to meet the requirements of the proposed Advanced Clean Cars program. 
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These expenditures would in turn bring about additional (indirect) changes in the 

California economy that may change the overall costs of the regulation to the economy. 

Increased vehicle prices, for example, may result in a reduction of demand for other 

goods and services as consumers use more of their money to pay for the price 

increase. California firms may respond by cutting back production and decreasing 

employment. On the other hand, in response to the proposed regulations automobile 

manufacturers are expected to choose technologies that reduce vehicle operating costs, 

leaving consumers with additional money to spend on products and services. This 

would, in turn, induce firms supplying those products and services to expand their 

production and increase their hiring of workers. A third type of effect occurs when 

purchase of the new vehicles directly lowers demand for the petroleum refining and 

gasoline distribution sectors. 

The changes caused by the proposed regulations will affect industries both negatively 

and positively. The net effect on the California economy of these activities hinges on 

the extent to which products and services are obtained locally. Using the E-DRAM 

model of the California economy, staff estimated the net effects of these activities on 

affected industries and the overall economy. The California industries and individuals 

affected most by the proposed Advanced Clean Cars program are those engaged in the 

production, distribution, sales, service, and use of light- and medium-duty vehicles as 

well as the refining and distribution of gasoline.

Table VII-C-1, Table VII-C-2, and Table VII-C-3 summarize the impacts of the proposed 

climate change regulations on the California economy for forecast years 2020, 2025, 

and 2030 respectively. The results of the E-DRAM simulation show that the changes 

caused by the proposed regulations would increase the California economic output by 

roughly $2 billion (0.1 percent) in 2020, $8 billion (0.2 percent) in 2025, and $14 billion 

(0.3 percent) in 2030. Personal income would increase more gradually, remaining 

almost unchanged in 2020 but increasing by roughly $3 billion (0.1 percent) in 2025, 

and $6 billion (0.2 percent) in 2030. As a result, California net employment impacts due 

to the proposed regulation would also remain about constant in 2020, but increase 

slightly by 21,000 jobs (0.1 percent) in 2025, and 37,000 jobs (0.2 percent) in 2030.

Table VII-C-1. Economic Impacts of the Proposed Advanced Clean Cars (ACC)

Regulations on the California Economy in Fiscal Year 2020 (2009 dollars)

California Economy Without ACC

Regulations

With ACC 

Regulations

Difference % of

Total

Output (Billions) $3,600 $3,602 $2 0.1

Personal Income (Billions) $2,171 $2,172 $1 0.0

Employment (thousands) 17,913 17,919 6 0.0

Note: Difference of individual columns may not match due to rounding.
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Table VII-C-2. Economic Impacts of the Proposed Advanced Clean Cars Regulations on 

the California Economy in Fiscal Year 2025 (2009 dollars)

California Economy Without ACC

Regulations

With ACC 

Regulations

Difference % of

Total

Output (Billions) $4,170 $4,178 $8 0.2

Personal Income (Billions) $2,525 $2,528 $3 0.1

Employment (thousands) 18,966 18,987 21 0.1

Note: Difference of individual columns may not match due to rounding.

Table VII-C-3. Economic Impacts of the Proposed Advanced Clean Cars Regulations on 

the California Economy in Fiscal Year 2030 (2009 dollars)

California Economy Without ACC

Regulations

With ACC 

Regulations

Difference % of

Total

Output (Billions) $4,881 $4,895 $14 0.3

Personal Income (Billions) $2,962 $2,968 $6 0.2

Employment (thousands) 20,179 20,216 37 0.2

Note: Difference of individual columns may not match due to rounding.

These results indicate that higher vehicle prices cause consumers to redirect their 

expenditures. Consumers would spend more on the purchase of motor vehicles, thus 

having less money to spend on the purchase of other goods and services. Since most 

automobile manufacturing occurs outside of the State, the increased consumer 

expenditures on motor vehicles would reduce California economic activity. However, 

the reduction in operating costs resulting from improved vehicle technology would 

reduce consumer fuel expenditures, leaving California consumers with more disposable 

income to spend on other goods and services. Businesses that serve local markets are 

most likely to benefit from the increase in consumer expenditures. The increase would 

in turn boost the California economy slightly, resulting in the creation of some additional 

jobs. 

The output from E-DRAM is based on the assumption that the future structure of 

California’s economy remains similar to current existing conditions. These results are 

thus only illustrative of the potential macroeconomic effects that might occur with the 

implementation of the proposed amendments as opposed to a forecast of future 

economic growth. The relatively small percentage change in this context means that 

the uncertainty of future economic structures may offset some of these positive effects. 

However staff believes it is unlikely that the proposed amendments per se would result 

in significant negative economic impacts. In fact, the technology-forcing nature of the 

program could stimulate growth in certain sectors, which would not be reflected in the 

model’s existing linkages between sectors. For instance, electric vehicle manufacturers 

and clean energy companies that have recently been established in the state would 

have the potential of expanding their businesses and exporting their products to other 
Page 201

parts of the country or the world, though conservatively such positive impacts are not 

assumed in the modeling. 

2. AFFILIATED BUSINESSES

The E-DRAM results reflect the overall impacts to the statewide economy. While 

positive at the aggregate level, some individual sectors may experience negative 

impacts. As the directly regulated automotive manufacturing sector currently has a 

limited presence in California, indirect effects on affiliated businesses are likely to be of 

greater interest. Potential effects are discussed qualitatively here and in a more 

quantitative fashion in section VIII.C.5 and Appendix S for affiliated businesses located 

in low-income cities.

The oil and gas industry, fuel providers, and service stations are likely to be the most 

adversely affected by the proposed Advanced Clean Cars program due to the 

substantial reductions in demand for gasoline – exceeding $1 billion beginning in 2020 

and increasing to over $10 billion in 2030. Some jobs could be transferred from 

refineries or fuel providers to the electricity generation or hydrogen production sectors 

or other unaffiliated businesses. Likewise, some service stations may be able to 

transition to providing alternative fuel types to offset these losses. However, a net loss 

to these businesses would be expected overall. 

Vehicle dealers may also be affected due to changes in vehicle sales. In 2010, 55 

percent of average new vehicle dealership revenue was generated by new vehicle sales 

and another 24 percent from used vehicle sales.46 The effect of the proposed program 

on vehicle price increases and subsequently on new and used vehicle sales are further 

discussed in section IX.A and IX.B. Those analyses suggest that new vehicle sales in 

California would increase slightly as a result of the proposed amendments, which would 

in turn increase dealer revenues due to the higher sales volume as well as the higher 

vehicle prices. However, the higher new vehicle sales may reduce populations of older 

vehicles, which could reduce business for the parts and servicing departments at 

dealerships (and independent repair shops). On the other hand, the greater penetration 

of new advanced vehicle technologies may result in servicing needs that can only be 

fulfilled at the dealership. Additionally, dealers may need to provide training to sales 

and servicing staff to familiarize them with many of the new ZEV technologies 

anticipated to be offered as a result of the proposed program. 

The effects on used vehicle dealers (or the used vehicle department at a new vehicle 

dealership) are more ambiguous. Higher sales volumes of new vehicles do not 

necessarily imply that used vehicle sales must fall. A vehicle can be sold only once new 

and some are never resold while others might be resold numerous times. New vehicle 

buyers frequently trade in an existing vehicle, generating both a new and used vehicle 

sale. In addition, assuming that the higher price of new vehicles translates into 

 46 California New Car Dealers Association 2011 Economic Impact Report, 

http://www.cncda.org/secure/GetFile.aspx?ID=2106 (Accessed November 2, 2011)
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proportionally higher used vehicle prices, this increase in revenue could offset some or 

all of the losses from reduced sales volumes.

3. ECONOMIC IMPACTS OUTSIDE OF CALIFORNIA

Although State rulemaking law does not require evaluation of economic impacts outside 

of California, the significant compliance costs imposed by both the LEV III and ZEV 

amendments warrants some consideration of the potential impacts at a broader level. 

ARB’s standard economic analysis assesses the per vehicle price increases on vehicles 

sold in California as applied by manufacturers located outside of the State. As 

described in section IX.A and IX.B, staff believes the proposed Advanced Clean Cars 

program could have a small positive effect on new vehicle sales in California, which in 

turn could imply growth for that sector and affiliated sectors. However, staff does not 

have the capability to evaluate quantitatively the effects of the proposed program on the 

broader economy surrounding those sectors. E-DRAM is not a suitable model for 

evaluating these potential effects as it treats everything outside of California as the “rest 

of the world” and makes no distinction between other states or other countries. 

However, as concurrent federal light-duty vehicle greenhouse gas emission regulations 

are expected to be promulgated in concert with the proposed Advanced Clean Cars 

program, an economic impact analysis at the national level would provide insights on 

the potential economy-wide impacts for other states besides California. Although no 

such analysis was conducted as part of the recent Notice of Proposed Rulemaking for 

2017 and Later Model Year Light-Duty Vehicle Greenhouse Gas Emissions and 

Corporate Average Fuel Economy Standards, an exploratory economy-wide impact 

analysis of the impacts of greenhouse gas tailpipe standards was undertaken by U.S. 

EPA as part of their MY2012-2016 rule47, which is indicative of the types of effects to 

expect from the MY2017-2025 National Program.

In its MY2012-2016 analysis, U.S. EPA used the Intertemporal General Equilibrium 

Model (IGEM), which is an economy-wide computable general equilibrium model for the 

United States economy. Based on changes in vehicle technology costs, fuel 

consumption, and fuel prices that would be expected from the MY2012-2016 rule, IGEM 

estimates changes in U.S. gross domestic product (GDP) and household consumption. 

Note that the value of additional private or societal benefits are not included in the 

modeling. The results show that U.S. GDP would increase for all years analyzed, on 

the order of 0.5 percent in 2020, 0.77 percent in 2030, and continuing to increase to 0.9 

percent in 2050. On the consumption side, households would decrease consumption 

by about 0.01 percent at the beginning of the rule due to the higher vehicle prices, but 

fuel savings would accumulate with time so that consumption would increase by 0.36 

percent in 2020, 0.92 percent in 2030, and reaching 1.5% in 2050.

Due to the similar nature of the proposed MY2017-2025 National Program, similar 

small, positive effects on U.S. GDP and household consumption would be expected as 

 47 Memorandum to Docket, "Economy-Wide Impacts of Proposed Greenhouse Gas Tailpipe Standards for the Final 

Rulemaking," March 4, 2010, Document ID: EPA-HQ-OAR-2009-0472-11467
Page 203

those for the prior rule. While such effects are unlikely to be perfectly distributed 

uniformly across all states, it is even more unlikely that these positive benefits occur 

only in California, with none occurring in the remaining 49 states. Indeed, like 

Californians, consumers in many other states would be expected to experience 

reductions in operating costs resulting from improved vehicle technology, leaving them 

with more disposable income to spend on other goods and services in their local 

markets. 

D. POTENTIAL IMPACT ON CALIFORNIA BUSINESS COMPETITIVENESS

Automobile manufacturing in California represents a small fraction of the State’s 

economy, less than 0.5 percent.48 The California businesses impacted by this 

regulation tend to be affiliated businesses such as gasoline service stations, automobile 

dealers, and automobile repair shops, as discussed above in section VII.C.2. Affiliated 

businesses are mostly local businesses. These businesses compete within the State 

and generally are not subject to competition from out-of-state businesses. Therefore, 

the proposed regulations are not expected to impose significant competitive 

disadvantages on affiliated businesses. 

Additionally, the GHG component of the LEV III amendments is being proposed in 

coordination with the MY2017-2025 National Program, which will impose similar impacts 

on businesses in other states. Therefore, affiliated businesses in California would be 

selling, repairing, and fueling similar vehicles as their competitors in other parts of the 

country, so there would be no benefit to relocating. For all other businesses that 

purchase new light-duty vehicles, vehicle prices would also be similar to those their 

competitors face in other states. As other countries adopt more stringent GHG 

standards, the same would be true of their global counterparts. These businesses 

would also experience similar operating cost savings as ordinary consumers, which can 

be reinvested back into the businesses and potentially increase their competitiveness. 

E. ANCILLARY BENEFITS

The economic impacts described above only consider the private benefits associated 

with reduced expenditures for operating future new vehicles that comply with the 

proposed Advanced Clean Cars program. However, the proposed regulations would 

also produce other societal benefits. Although these societal benefits are not monetized 

for inclusion in a formal benefit-cost analysis or incorporated into the cost effectiveness 

calculations, they are discussed here for completeness. 

1. SOCIAL COST OF CARBON

The social cost of carbon (SCC) is a monetary estimate of future damages resulting 

from the emission of one additional metric ton of carbon dioxide in a specific year.49 

 48 Based on the share of output from the vehicle manufacturing sector assumed in E-DRAM. 49 SCC values discussed in this section apply only to carbon dioxide emissions. Values for other greenhouse gases 

(GHGs) are under development.
Page 204

Given the consensus that climate change caused by anthropogenic emissions of carbon 

dioxide, (CO2), and other GHGs will result in widespread, long-term environmental and 

economic damage, it would be inconsistent to assign a zero value to the reduction of 

climate change emissions. Regulations that reduce future CO2 emissions benefit the 

environment and the economy by preventing damages. Recognizing the need to assign 

value to the social costs of GHG emissions, ARB staff monetizes the social benefits of 

the proposed rule’s reduction of CO2 emissions using global SCC values published by 

the U.S. government. Due to the provisional and uncertain nature of these estimates 

however, ARB staff calculates these values for illustrative purposes but does include 

them in the primary economic impact analysis or cost-effectiveness estimates. 

Federal agencies have developed and applied a range of global SCC values in 

regulatory impact analyses (RIAs) since 2008. The U.S. government is committed to 

periodically reviewing and updating SCC values. Its current SCC values result from 

averaging the outputs of three peer-reviewed integrated assessment models (IAMs).50 

The interagency group selected four different values for the social cost of CO2

emissions in any given year: three values based on the average SCC across models 

and socio-economic and emissions scenarios, discounted at 2.5%, 3% and 5% rates; 

and a fourth value – the 95th percentile of model estimates -- to represent higher-thanexpected or catastrophic damages. (See Table VII-E-1-1.) Taking one example from 

the table, $33 represents the stream of future damages caused by the emission of one 

additional metric ton of CO2 in the year 2030, when those post-2030 damages are 

discounted at 3%. To estimate the social benefits of an entire regulatory program, SCC 

values ($) for all impacted years are multiplied by annual CO2 emission reductions (MT 

CO2), converted to a net present value using the same discount rate (3%) and summed. 

Additional details related to the estimation, selection and application of the social cost of 

carbon can be found in Appendix S.

 50 “Social Cost of Carbon for Regulatory Impact Analysis under Executive Order 12866,” February 2010, EPA-HQOAR-2009-0472 See pages 5-11 for discussion of the three integrated assessment models.
Page 205

Table VII-E-1-1. SCC Values: Federal Interagency Working Group

Global Social Cost of CO2 Emitted in 2020, 2025, 2030, & 2040

(2009$/Metric Ton)51

Discount 

Rate 5% 3%“Central Value” 2.5% 3%

Emissions 

Year Avg., 3 models Avg., 3 models Avg., 3 models 95th percentile

2020 $7 $27 $43 $84

2025 $8 $31 $47 $94

2030 $10 $34 $52 $103

2040 $13 $41 $60 $123

Source: Social Cost of Carbon for Regulatory Impact Analysis under Executive Order 12866, U.S. 

Interagency Working Group on Social Cost of Carbon, 2010

Future damages from climate change are discounted to reflect society’s marginal rate of 

substitution between consumption in the present and in the future. The working group 

emphasizes the use of a range of SCC values to reflect the uncertainties of estimating 

the future benefits of reducing CO2 emissions, but identifies the value discounted at 3% 

as its “central value.” Discount rates of 3% and 7% are often used for social discounting 

in the context of Federal regulatory programs, however, the Office of Management and 

Budget’s Circular A-4 suggests using a lower, but still positive discount rate when 

considering inter-generational costs.52 

Despite the use of discounting to calculate the net present value of future benefits, the 

interagency group’s annual unit SCC values increase over time. Future emissions are 

expected to become more damaging as physical and economic systems become more 

stressed in response to increased climatic change.

The proposed rule will substantially reduce combustion, distribution, refining and 

extraction of gasoline for an extended period. The private economic benefits that 

accrue to vehicle owners as a result of the rule, (fuel savings, e.g.), are quantified and 

discussed in the economic impact analysis in section VII-B.

Additional economic benefits – social benefits – can be attributed to the global climate 

change impacts of reducing fuel production, distribution and combustion. Applying 

global SCC values to the emission reductions of carbon dioxide estimated from the 

proposed Advanced Clean Cars program results in the SCC benefits shown in Table 

VII-D-1-2. Amounts are expressed in billions of 2009 dollars and represent the net 

 51 Table values differ marginally from those in the U.S. EPA Preamble (76 Fed.Reg. No. 231, December 1, 2001, 

Table III-70, p. 75128) because U.S. EPA uses a GDP price index rather than a consumer price index to adjust for 

inflation.

52 Executive Office of the President, Office of Management and Budget, Circular A4, Regulatory Analysis, September 

17, 2003. See Section E, Identifying and Measuring Benefits and Costs, Discount Rates, 4. Intergenerational 

Discounting. Accessed 11/17/11 at: http://www.whitehouse.gov/omb/circulars_a004_a-4/#e
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present value of climate change damages avoided as a result of CO2 emission 

reductions in the specified year(s). For the “Central Value,” which discounts future 

benefits at 3% annually, the proposed regulation would avoid $20 billion of climate 

change damages through 2040.

Table VII-D-1-2. Social Benefits of Projected Advanced Clean Cars CO2 Emission 

Reductions

Global Social Benefits of ACC CO2 Reductions, (Billions of 2009$) in 

Selected Years and Cumulated through 2040

Discount 

Rate 5% 3%“Central Value” 2.5% 3%

Emissions 

Year Avg., 3 models Avg., 3 models Avg., 3 models 95th percentile

2020 $0.03 $0.10 $0.16 $0.30

2025 $0.13 $0.49 $0.75 $1.5

2030 $0.28 $0.95 $1.4 $2.9

2040 $0.56 $1.7 $2.6 $5.2

2017-2040 $5.9 $20 $30 $59

Combining the estimated social benefits of projected CO2 emission reduction with the 

private economic benefits discussed in section VII.B improves the overall benefit-cost 

ratio of the proposed rule. However, the social benefits of CO2 emission reduction were 

not considered in setting the stringency of the proposed ACC-GHG standards.

Had SCC been integrated with the primary economic impact analysis for the proposed 

program, its inclusion would not have significantly impacted ACC’s overall benefit-cost 

ratio as seen in Figure VII-D-1-1, below. This is because the private value of fuel 

exceeds the estimated social cost of the GHG-related externality associated with its 

combustion.
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Figure VII-D-1-1. Benefit-Cost Ratios of ACC through 2040 with and without Social Cost 

of Carbon (Millions of 2009$)

2. ADDITIONAL ANCILLIARY BENEFITS

The avoidance of future damages from carbon dioxide emissions as represented by the 

social cost of carbon is one of many ancillary benefits that are not included in the 

primary economic impact analysis. Other benefits not monetized nor included are:

• Valuation of avoided morbidity and mortality impacts from criteria pollutant 

emission reductions;

• Consumer surplus from additional vehicle miles traveled;

• Upstream reduction of criteria pollutant emissions from fuel distribution;

• Refueling Time Savings;

• California’s contribution to national energy security benefits.

The 2017 and Later Model Year Light-Duty Vehicle Greenhouse Gas Emissions and 

Corporate Average Fuel Economy Standards proposed by U.S. EPA and NHTSA offers 

energy security benefits by reducing the risk of national macroeconomic disruptions 

caused by oil price volatility.53 California’s implementation of the proposed Advanced 

Clean Cars program and subsequent reductions in petroleum-based fuel consumption 

would contribute to similar energy security benefits after 2016. 

 53 Preamble, 76 Fed.Reg. No. 231, December 1, 2011, Table III-75, p. 75137.

-$100,000

-$50,000

$0

$50,000

$100,000

$150,000

$200,000

$250,000

SCC @ 3%

Savings

Operating

Cost Savings

Vehicle

Compliance

Costs

Benefit-Cost Ratio: 3.6 to 1 Benefit-Cost Ratio: 3.3 to 1

ACC

with

SCC

ACC

without

SCC
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Some ancillary benefits, such as refueling time savings, are uncertain because they 

depend on future automobile design choices. Others would incur related dis-benefits. 

For example, incremental VMT would increase accidents, traffic congestion and noise 

as well as consumer surplus. Nonetheless, when estimated and monetized at the 

federal level by the USEPA in the context of the National Program for MY2017-2025, 

the benefit of increased travel outweighs the associated dis-benefits.54

If all these additional ancillary impacts of California’s proposed regulations were 

quantified and monetized using the methods applied by U.S. EPA for the National 

Program, estimated net program benefit would increase, and the overall benefit-cost 

ratio would further improve.

F. POTENTIAL COSTS TO LOCAL AND STATE AGENCIES

Fiscal impacts on local and State agencies would not occur within the next three fiscal 

years. However, due to the potential magnitude of impacts in future fiscal years, they 

are discussed here to illustrate the possible scale of the problem. Lower fuel 

consumption by the new complying vehicles would affect gasoline and vehicle sales tax 

revenues. Gasoline taxes include fixed State and federal excise taxes, and the State 

sales tax. If tax rates remain at current levels, staff estimates that the Advanced Clean 

Cars program could result in gasoline excise and sales tax revenues declines of about 

$250 million in 2020 (compared to the no regulation scenario), of which about half could 

be offset by increased sales taxes from higher priced vehicles. In 2025, fuel-related tax 

revenues could decline by more than $1 billion compared to a no regulation scenario, of 

which about $250 million could be offset by increased vehicle sales tax revenues. By 

2030, fuel-related tax revenues could decrease by as much as $1.9 billion while vehiclerelated Sales tax revenues would continue to be about $230 million more, leading to a 

net shortfall of $1.7 billion. In the absence of any adjustments by the Legislature to 

generate additional revenues, shortfalls of these magnitudes could lead to significant 

underfunding of road maintenance, transit funding, and other government services. 

Although not quantified, it is expected that a considerable percentage of the fuel savings 

resulting from the proposed regulations will be redirected towards goods and services 

subject to sales tax, in which case some of the tax revenues, in addition to increased 

vehicle sales taxes, would be recouped. However, there is no guarantee that these 

revenues would be dedicated to transportation-related purposes as would be the case 

with state and federal excise tax revenue.

California Energy Commission analysis of the Department of Motor Vehicle database for 

2009 shows there were about 300,000 light-duty vehicles registered to State and local 

agencies in California. EMFAC 2011 estimates the total population of light-duty 

vehicles in 2009 at about 22.8 million, meaning that government owned vehicles 

comprise about 1.3 percent of the total state fleet. The data also show that 

governments owned about 11,000 MY2009 vehicles. Taken as a proxy for annual 

purchases, this represents about 1.3 percent of all MY2009 light-duty vehicles 

 54 Preamble, 76 Fed.Reg. No. 231, December 1, 2001, Table III-83, p. 75147.
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estimated in EMFAC2011. Government fleets are thus a small share of the total 

California market and would not be expected to bear a significant portion of the 

compliance costs. Furthermore, the staff analysis below for individual consumers 

indicates that the increased initial price is more than offset by operating cost savings 

over the life of the vehicle. Assuming that typical agency-owned vehicles are driven 

similar amounts as those owned by California households, staff expects that the same 

would hold true for public agencies—savings from the lower operating costs of the 

proposed regulation would outweigh the higher price that the State and local agencies 

would pay for vehicles in 2017 and later. In cases where government vehicles are 

driven more or less than typical household vehicles, the savings would accrue faster or 

slower, but still pay back within the lifetime of the vehicle. While these proposed 

amendments would not yield fuel savings for MY2015 and MY2016 vehicles, these 

vehicles would still have reductions in operating costs resulting from prior rulemakings 

that would far exceed the minimal compliance costs associated with the early phases of 

the tightened criteria pollutant standards.

G. POTENTIAL IMPACT ON MONTHLY LOAN PAYMENT AND OPERATING 

SAVINGS FOR NEW VEHICLES

To provide a perspective on the potential impact of the proposed regulations on the 

monthly cash flow for typical purchasers of new vehicles, staff considered a vehiclefinancing period of five years at an interest rate of 5 percent. Table VII-G-1 provides 

estimates of potential increases in monthly loan payments and decreases in operating 

costs based on the average increases to vehicle prices when the regulation is fully 

phased-in (MY2025). Fuel savings are estimated based on the EMFAC2011 model 

estimates of the annual average vehicle miles traveled (VMT) in the vehicle’s first five 

years of life with additional VMT added to account for the rebound effect. Overall, lightduty vehicles are estimated to travel on the order of 17,000 miles annually during their 

first five years. See Appendix S for additional details on payback and savings 

calculations. 

As shown in Table VII-G-1, the proposed Advanced Clean Cars program is expected to 

increase the price of new MY2025 average fleet vehicle by about $1,900. For vehicles 

that are financed, this would increase the average monthly payment for a typical 

consumer about $35. Concurrently, typical consumers would benefit from monthly fuel 

savings of about $48 producing a net monthly savings of about $12 and net lifetime 

savings of roughly $4,000. These savings would pay back the initial increase in vehicle 

purchase price in less than three years. 
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Table VII-G-1. Potential Impact on Monthly Loan Payment and Operating Savings for New 

2025 MY Vehicles (2009 dollars)

Description Advanced Clean 

Cars Program

Average Increase in New Vehicle Price $1,900

Increase in Monthly Loan Payment $35

Net Lifetime Savings $4,000

Monthly Operating Savings $48

Net Monthly Savings $12

Payback Period (Years) 2.9

Note: Estimates have been rounded. Costs and savings include ZEVs and their 

additional expenditures on electricity and hydrogen.

In the event that only the proposed LEV III (including GHG) amendments are adopted, 

average new vehicle prices would increase by only $1,400, which translates to 

increases in monthly payments of $26 assuming the entire incremental vehicle price has 

been financed. At the same time, consumers on average would reduce fuel 

expenditures by $50 each month, for a net monthly savings of $24. Over the life of the 

vehicle, net fuel savings would total $4,800 after accounting for the higher initial 

purchase price. The lower compliance cost and greater fuel savings would reduce the 

payback period to only two years. 

It should be noted here that most vehicles still retain about half of their original value 

after a five-year financing period. These values would effectively reduce the increase in 

monthly payments if they were realized after the completion of the loan payments. Even 

without the realization of the residual value, monthly savings from new vehicle 

operations exceed the increase in monthly loan payments for both the passenger car 

and light-duty truck categories. 

H. JUSTIFICATION FOR ADOPTING REGULATIONS DIFFERENT FROM 

FEDERAL REGULATIONS

To the extent California’s regulations differ from current federal requirements affecting 

the same pollutants, California has authority to set its own standards to reduce 

emissions further to meet federal and state ambient air quality standards and climate 

change requirements and goals, and to require additional and separate reporting. The 

differing state requirements proposed are necessary to achieve additional benefits for 

human health, public welfare, and the environment as envisioned by authorizing 

legislation.

I. CONCLUSION

The proposed Advanced Clean Cars program has a small, net positive impact on the 

State's economy. The regulation may lead to a small, net creation or expansion of 

businesses, and could increase jobs in California. Because affected businesses are 
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primarily local, there will not be any impact on the ability of California businesses to 

compete with businesses in other states. State and local agencies will not be adversely 

impacted and are likely to realize a net reduction in their cost of fleet operations. 

Consumers would likewise quickly recoup the additional vehicle costs through savings 

in operating costs.

VIII. IMPACTS ON MINORITY AND LOW-INCOME COMMUNITIES

This section provides information on ARB's activities to reach out to minority and lowincome communities in the development of the Advanced Clean Cars regulations.

Staff also has assessed whether the regulation would impose economic or 

environmental impacts on minority or low-income communities.

A. ARB ENVIRONMENTAL JUSTICE POLICY

ARB has made the consideration of environmental justice an integral part of its 

activities. State law defines environmental justice as the fair treatment of people of all 

races, cultures, and incomes with respect to the development, adoption, 

implementation, and enforcement of environmental laws, regulations, and policies.

The Board approved Environmental Justice Policies and Actions (Policies) on 

December 13, 2001. These Policies establish a framework for incorporating 

environmental justice into ARB's programs consistent with the directives of State law. 

The Policies apply to all communities in California, but recognize that environmental 

justice issues have been raised more in the context of low-income and minority 

communities.

1. AB 1493 REQUIREMENTS

Assembly Bill 1493 emphasizes the importance of considering the economic impacts of 

the climate change regulations on communities in an environmental justice context. 

The bill specifically directs ARB to, "consider the impact the regulations may have on 

the economy of the State, including, but not limited to...the ability of the State to 

maintain and attract businesses in communities with the most significant exposure to air 

contaminants, localized air contaminants, or both, including, but not limited to, 

communities with minority populations or low-income populations, or both."

The bill also recognizes the importance of engaging these communities throughout the 

regulatory development process and includes specific requirements that ARB "conduct 

public workshops in the State, including, but not limited to, public workshops in three of 

the communities in the state with the most significant exposure to air contaminants or 

localized air contaminants, or both, including, but not limited to, communities with 

minority populations or low-income populations, or both."
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2. AB 32 REQUIREMENTS

Assembly Bill 32 also includes specific language regarding communities in an 

environmental justice context. The bill specifically directs ARB to, “coordinate with State 

agencies, as well as consult with the environmental justice community, industry sectors, 

business groups, academic institutions, environmental organizations, and other 

stakeholders in implementing this division.” It also recognizes the importance of 

engaging these communities throughout the regulatory development process and 

includes specific requirements that ARB “shall conduct a series of public workshops to 

give interested parties an opportunity to comment on the plan. The State board shall 

conduct a portion of these workshops in regions of the State that have the most 

significant exposure to air pollutants, including, but not limited to, communities with 

minority populations, communities with low-income populations, or both.”

AB 32 also requires, “that activities undertaken to comply with the regulations do not 

disproportionately impact low-income communities” and that “the State board shall 

ensure that the greenhouse gas emission reduction rules, regulations, programs, 

mechanisms, and incentives under its jurisdiction, where applicable and to the extent 

feasible, direct public and private investment toward the most disadvantaged 

communities in California and provide an opportunity for small businesses, schools, 

affordable housing associations, and other community institutions to participate in and 

benefit from statewide efforts to reduce greenhouse gas emissions.”

Finally, AB 32 requires ARB, before including any market-based compliance 

mechanism, to “Consider the potential for direct, indirect, and cumulative emission 

impacts from these mechanisms, including localized impacts in communities that are 

already adversely impacted by air pollution.”

3. OUTREACH TO MINORITY AND LOW-INCOME COMMUNITIES

Staff conducted workshops in communities with environmental justice concerns. The 

dates of all the workshops were as follows:

Date Location

July 12, 2011 Fresno

July 19, 2011 Pacoima

July 26, 2011 Oakland

Each of the three workshops included an expert panel with opening remarks from a 

local community leader. The panels included one expert that focused on background 

information and environmental impacts of air pollution, one expert in the medical field 

that focused on the health impacts of air pollution, one expert from the American Lung 

Association of California that discussed their report titled “The Road to Clean Air,” and 

in some areas we also had an expert speak about local concerns. For instance in 

Fresno we had a speaker address agriculture. Having local community members and 

leaders participate in the workshops was greatly appreciated and added value and a 
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local context to ARB's presence in these communities. After community members 

heard from the panel members, staff presented information about the Advanced Clean 

Cars regulations and the CEQA scoping process (as discussed in Appendix B).

There were a number of different comments and concerns expressed at each workshop 

and staff was able to engage in a good dialogue with attendees about many air quality 

and climate change related issues. 

In general, community leaders and community members were very supportive of the 

work ARB is doing to take steps to reduce emissions from passenger cars and light-duty 

trucks.

B. POTENTIAL ENVIRONMENTAL IMPACTS

The Advanced Clean Cars regulations provide many air quality benefits to communities 

with environmental justice concerns. In addition to improved air quality from cleaner 

cars, there are upstream benefits associated with reduced petroleum shipping and

refining and retail fuel distribution. Many of the related shipping and processing facilities 

are located in or near low-income and minority communities. Importation and 

distribution of petroleum takes place in ports and along freeway corridors near 

communities often identified with environmental justice concerns. Staff therefore has not 

identified any mechanisms by which the Advanced Clean Cars regulation would result in 

a disproportionate or negative impact on low-income or minority communities. As 

indicated above in section V.E., overall fuel-related activities will result in a decrease in 

such upstream emissions. As a result, these upstream emission reductions are likely to 

provide benefits to these communities.

C. POTENTIAL ECONOMIC IMPACTS

Staff has evaluated the economic effects of the Advanced Clean Cars program on lowincome households. For those households that purchase new vehicles, the economic 

effects of the regulations would be no different than on any other consumer. However, 

because residents in low-income communities tend to purchase used vehicles at a 

higher rate than residents in middle- and high- income communities, staff evaluated the 

effects of the regulation on the used vehicle market and, more specifically, on lowincome households that purchase used vehicles. Effects on employment and 

businesses in low-income communities are also discussed. Staff invites comment on 

other possible economic impacts.

1. POTENTIAL IMPACT ON A TYPICAL LOW-INCOME HOUSEHOLD

The proposed Advanced Clean Cars regulations are likely to require changes in vehicle 

technology that will increase the price of new vehicles sold in California. This increase 

in turn is expected to increase the price of used vehicles. Low-income households often 

purchase used vehicles. In this analysis, California households of three members with 

an annual family income of roughly $18,500 or less are considered to be economically 
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disadvantaged.55 According to the 2009 National Household Travel Survey56 lowincome households with an average annual income below $20,000 (closest bracket to 

poverty level of $18,500) tend to own vehicles with an average age of 11 to 13 years.

The impact on low-income used car buyers was assessed by considering the annual 

vehicle price increase as a percent of income. The analyses showed that the proposed 

regulations should not have a significant impact on low-income households that 

purchase used cars. 

2. APPROACH

The approach used to assess the potential impact of the proposed regulations on typical 

low-income purchasers of used vehicles is outlined here:

(1) Changes in the average price of used vehicles caused by the proposed Advanced 

Clean Cars program were estimated using historical used vehicle values from the 

National Automobile Dealers Association. For example, a $500 increase in the price of 

a new vehicle belonging to the passenger car category would be expected to increase 

the price of a 10-year-old vehicle by $100 assuming a residual value of 20 percent.

(2) Changes in prices of used vehicles were annualized over the remaining life of the 

vehicles. For example, an $100 increase in the price of a 10- year-old used passenger 

car is equivalent to a $23 annual cost increase for the vehicle over its median remaining 

useful life of 6 years.

(3) The annualized cost increase was compared with the median income of typical lowincome households to assess the extent of the impact on typical low-income household 

purchasers of used vehicles.

3. ASSUMPTIONS

The following assumptions were used to estimate the potential economic impacts of the 

proposed regulations on typical low-income households: 

(1) The proposed regulations would increase the fleet average price of a new vehicle by 

about $1900 when the regulation is fully phased in MY 2025. This price increase 

includes ZEV technologies that tend to be more expensive. To the degree that lowincome households would be more likely to purchase vehicles with conventional 

technologies, the use of the fleet average price increase would overestimate their costs.

 

55 Based on U.S. Department of Labor and U.S. Department of Health and Human Services, 2011 Poverty Guidelines 

(http://aspe.hhs.gov/poverty/11poverty.shtml, Accessed September 22, 2011) 56 http://nhts.ornl.gov/index.shtml, Accessed September 22, 2011
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(2) Most low-income households purchase vehicles that are at least 10 years old. This 

assumption is based on the information obtained from the 2009 National Household 

Travel Survey. 

(3) A 10-year-old used passenger car has a retention value of about 20 percent. A 10-

year-old light-duty truck has a retention value of about 29 percent. The average 10-

year-old light-duty vehicle has a retention value of 23%.57

(4) A real discount rate of 10 percent was used for this analysis even though the interest 

rate on used car loans averaged around 9 percent in the past 10 years58. Given the 

unusually low recent interest rates, this rate was rounded upward upwards to 10 percent 

to be closer to pre-recession levels.

(5) New passenger cars are expected to have median useful life of 14 years, and new 

large trucks and minivans have a median useful life of 17 years.59 Based on the data 

from EMFAC, a 10- year-old car has a median remaining useful life of 6 years and a 10-

year old truck has a median remaining useful life of 9 years.60

(6) According to the 2011 Federal Poverty Guidelines, California households of three 

with an annual family income of $18,500 or less are considered to be economically 

disadvantaged. 

4. RESULTS

Typical California low-income households are affected by the proposed Advanced 

Clean Cars program to the extent that the implementation of the regulations would alter 

their annual disposable income. Using the previously stated assumptions, staff 

estimated that the increase in annual costs of used vehicles represents about 0.5 

percent of the annual family income of $18,500 for a low-income household, as shown 

in Table VIII-C-4-1. This represents a minor change in the average income of typical 

low-income households. Larger households are considered economically 

disadvantaged at higher income levels so their poverty guideline income level is higher 

In cases where they are purchasing similarly priced 10-year old vehicles, the annual 

cost increases would represent an even smaller percentage of their annual income (i.e. 

dividing the same incremental price by a higher income level).

The analysis discussed here assumes that low-income households would be able to 

finance the increase in used car prices either from their own income or from borrowing. 

As shown in Table VIII-C-4-1, the average increase in used vehicle prices would be 

$440 for a 10-year-old MY2025 vehicle (in calendar year 2035). It is possible that some 

 57 Analysis of National Automobile Dealers Association Used Vehicle Values for 1994-2004. 58 US Federal Reserve Historical Car Loan Data http://www.federalreserve.gov/releases/g20/hist/fc_hist_tc.txt

(Accessed September 20, 2011)

59 Based on the age when the EMFAC2011 survival probability is less than 50%. 60 Based on the age when the EMFAC2011 survival probability is less than 50% of the survival probability of a 10-

year-old vehicle, e.g. a 10-year-old passenger car has a survival probability of 76%, the age of a vehicle with a 

survival probability less than 38% is 16 years old.
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low-income households may have difficulty raising this amount in additional funds to 

purchase their vehicles. However, staff notes that this average price increase includes 

a sizeable share of zero-emission vehicles with greater incremental costs. Isolating 

only conventional vehicle technology, the average increase of used vehicles is 

significantly lower, on the order of $200 per vehicle which translates to an annualized 

cost of $40 over seven years and represents only 0.2 percent of the annual family 

income of $18,500. 

Table VIII-C-4-1. Potential Impacts of Proposed Advanced Clean Cars Program on LowIncome Households (2009 dollars)

Description Advanced Clean 

Cars Program

Average Increase in New 2025 MY Vehicle Prices $1,900

Average Increase in Used 2025 MY Vehicle Prices $440

Median Remaining useful life (years) 7

Annualized Cost of Used Vehicle $90

Poverty Guideline Income Level $18,500

Share of Annual Income 0.5%

Note: Table values have been rounded and may not reproduce exactly using assumptions described. 

The proposed GHG standards directly consider the importance of the lowest cost 

vehicles via the construction of the footprint-indexed standards. The footprint-indexed 

standards intentionally utilize a modification to the otherwise linear CO2-to-size 

relationship to accommodate the difficulties of applying costly technologies to smaller 

relatively low cost vehicle classes such as subcompact and compact cars. The standard 

targets intentionally do not require the same percent reductions in CO2 emissions for 

cars less than 41 ft2 with the “kink” in the standard target line at that size. These target 

lines effectively make it so that cars smaller than that threshold do not receive more 

stringent standards (see Figure III-A-3-2 and Figure III-A-5-1 above). These lowest-cost 

subcompact and compact cars typically are priced in the $14,000 to $16,000 range. To 

the extent that low-income purchasers are purchasing new cars, these lowest-cost, 

smaller vehicles have less stringent standards and therefore would have less additional 

new technology and lower incremental cost than the average values used in this 

analysis.

The Advanced Clean Cars program may cause vehicle prices to increase, however like 

other consumers who pay higher prices for their vehicle, they will also see a significant 

reduction in vehicle operating costs. The savings far outweigh the annualized cost of 

purchasing the vehicle (price increase spread over the years of ownership). Purchase 

prices may increase by a small percentage of their income, but will be more than offset 

by the operating cost savings, as discussed in the next section.
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4.1. Potential Impact on Monthly Loan Payment and Operating Savings

To assess the potential impact of the proposed regulations on the monthly cash flow of 

typical low-income purchasers of used vehicles, we consider a vehicle financing period 

of three years at an interest rate of 10 percent. Although recent average used vehicle 

loan periods are closer to 5 years, we assume three years as a more conservative 

assumption given that these vehicles may be approaching the end of their life. Table 

VIII-C-4-2 below provides estimates of the potential increases in monthly payments and 

decreases in operating cost savings. As shown in the table, the proposed Advanced 

Clean Cars program is expected to increase the monthly payment for an average 10-

year-old MY2025 vehicle (i.e., in the year 2035) by about $14. Concurrently, typical lowincome consumers would benefit from monthly operating cost savings of about $36, 

resulting in a net monthly savings of around $20. The vehicle miles traveled (VMT) are 

estimated using EMFAC2011 age-specific accrual rates, which for 10-year-old vehicles 

average around 12,000 miles per year. Over the remaining life of the vehicle, the 

vehicle would generate $2,000 of net savings after factoring in the additional $440 

average price increase. Households with higher or lower VMT would accrue greater or 

fewer net savings. The fuel savings would payback the initial costs in less than one 

year.

Table VIII-C-4-2. Potential Impact on Monthly Loan Payment and Operating Cost Savings 

for Used 2025 Vehicles Resulting from Advanced Clean Cars Program (2009 dollars)

Description Advanced Clean 

Cars Program

Average Increase of Used MY2025 Vehicle Price in 2035 $440

Increase in Monthly Loan Payment $14

Net Lifetime Savings $2,000

Monthly Operating Cost Savings $36

Net Monthly Savings $22

Payback Period (years) 0.9

As previously discussed, the average price increase includes a sizeable share of zeroemission vehicles with greater incremental costs. Assuming that low-income 

households would be more likely to purchase conventional vehicle technologies, the 

average increase for a used MY2025 vehicle would be closer to $200. If this entire 

amount were financed, monthly loan payments would increase on average by $7, 

however these consumers would save almost $30 each month in operating costs for a 

net savings of $23. Over the life of the vehicle, net savings would average around 

$1,700 and pay back the higher purchase price in about half a year.

It should be noted here that most used vehicles continue to retain a portion of their 

value after a three-year financing period. These values tend to effectively reduce the 

increase in monthly payments if the vehicle is resold after completion of the loan 

payments. Even without the realization of the residual value, monthly savings from 

vehicles impacted by the regulation exceed the increase in monthly loan payments.
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5. ECONOMIC IMPACT ASSESSMENT ON AFFILIATED BUSINESSES IN LOWINCOME CITIES OF CALIFORNIA

This section evaluates potential economic impacts that the proposed Advanced Clean 

Cars program may have on low-income cities in California, defined as cities whose 

poverty levels were at or over 13.2 percent. The low-income cities were home to 

approximately 15 million Californians or about 41 percent of the California population in 

2009. Of these 15 million Californians, 2.9 million or 19 percent were considered to be 

low-income. Figure VIII-C-5-1 shows the locations of low-income cities on the California 

map.

Figure VIII-C-5-1. Low-Income Cities in California

Section 43018.5 (e) of the California Health and Safety code requires an assessment of 

the impact of the proposed clean car regulations on businesses affiliated with the auto 

industry, especially those located in low-income communities. These businesses fall 

into twenty-three standard industrial classifications (SIC). ARB staff identified 37,144 

businesses in low-income cities in California. These businesses employed over 

210,000 people and generate about $27 billion in annual sales. On average, a typical 
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affiliated business generated about $722,000 in revenues per year or about $127,000 

per employee. (See Appendix S for additional details) 

Affiliated businesses in low-income cities are affected by the proposed Advanced Clean 

Cars program to the extent that implementation of the regulations would change their 

profitability. Using the assumptions described in Appendix S, staff estimated the impact 

on profitability of affiliated businesses. The impact on profitability would be the most 

severe for gasoline service stations. The affected service stations would experience an 

estimated decline of almost $740 million in revenues and about $6.4 million in profits. 

The profitability impact on manufacturers of automotive parts and bodies would be 

positive but that on auto repair shops would be negative. As a result, service stations 

are expected to lose approximately 2,300 jobs and auto repair shops about 2,200 jobs 

as a result of an assumed decrease in older vehicles. These job losses, however, are 

likely to be offset partially by the creation of 350 jobs by manufacturers of auto body and 

parts. No change is expected on the profitability or employment of new automotive 

dealers. The gain in profit associated with the 5 percent increase in sales volume is 

estimated to be roughly equivalent with the decrease in profit associated with the 

assumed 5 percent reduction in used vehicle sales. 

Based on the change in revenues and the average revenue per business, the proposed 

regulations are estimated to result in the equivalent elimination of 324 service stations, 

112 used car and parts dears, and 669 auto repair shops in low-income cities in 

California while 21 auto body and parts manufacturers are created. The loss of these 

businesses would reduce the number of businesses in low-income cities by less than 

0.1 of one percent of the over 1.2 million total businesses in low-income cities in 

California in 2009.61 The proposed regulations are also expected to result in the 

creation or expansion of numerous unaffiliated businesses, depending upon where the 

consumers redirect their savings from the reduction in fuel consumption and repair 

costs. Affiliated businesses are mostly local businesses. These businesses mostly 

compete against each other and are not subject to competition from out-of-state 

businesses. Therefore, the proposed regulations are not expected to impose significant 

competitive disadvantages on affiliated businesses. 

Note that this analysis represents a static approach that assumes no growth in 

population, employment, VMT, etc. Although this approach usually tends to 

overestimate the immediate impact a regulation, these simplifying assumptions are 

appropriate for this type of analysis when the economy-wide impact of a regulation is 

small. Section V shows that the proposed amendments could lead to a very slight 

increase in demand for travel that would increase the demand for gasoline and reduce 

the impact on service stations from what is anticipated here. Additionally, our analysis 

represents a partial equilibrium evaluation of the impact of the proposed regulations on 

affiliated businesses only. The analysis does not include the positive impact of the 

proposed regulations on unaffiliated businesses. As described in Section VII, the 

reduction in fuel consumption is expected to save consumers a significant amount of 

money. Part of the consumer savings is likely to be spent on non-liquid fuel such as 

 61 Based on Dunn and Bradstreet Market Insight (subscription data).
Page 220

electricity and the balance will be spent on other consumer products and services. 

Depending upon where the consumers direct their expenditures, many unaffiliated 

businesses will benefit from the proposed regulations. Because of higher average 

economic multipliers of unaffiliated sectors relative to service stations and repair shops, 

staff believes the numbers of jobs created by these businesses significantly exceed the 

number of jobs lost from service stations and auto repair shops. 

IX. OTHER CONSIDERATIONS 

A. CONSUMER RESPONSE EFFECTS ON EMISSIONS AND STATE ECONOMY

ARB’s Advanced Clean Cars program will increase new vehicle prices, starting with 

model year 2015. In addition to an increase in price, however, it is expected that many 

of the technologies that manufacturers employ to lower GHG emissions to comply with 

the regulation (including the production of Zero-Emission Vehicles) will, as an 

outgrowth, result in vehicles with lower operating costs than comparable pre-regulation 

vehicles. AB 1493 requires ARB to evaluate such operating costs as a component of 

owner or operator life-cycle costs, and AB 32 requires ARB to design its regulations 

seeking to maximize total benefits to California and consider overall societal benefits.

Changes in vehicle prices and other attributes may affect consumer purchase decisions. 

For example, not all consumers would be willing to pay more for the vehicle that they 

might have otherwise purchased. Some may purchase a different vehicle 

commensurate with their budget, including a used vehicle instead of a new vehicle. 

Others may wait until the following year, or respond in some other way. Still other 

consumers may be willing to pay the additional up front cost for greater future 

reductions in operating cost, in which case the vehicle would be more attractive. Such 

decision changes, referred to as consumer response, can affect the California vehicle 

fleet mix and possibly emissions. ARB estimates show that even if there is a consumer 

response to potential price increases and changes in operating costs, the staff 

proposal—the Advanced Clean Cars program as a whole—would continue to have a 

positive effect on tailpipe criteria pollutant emissions. 

1. BACKGROUND

A model known as CARBITS, was used to estimate consumer response (i.e., the 

estimated change in the type and number of vehicles sold) to changes in new vehicle 

attributes. The model is explained in greater detail in Appendix S. The attribute 

changes considered are the vehicle price increases necessary to cover the estimated 

compliance costs of the criteria pollutant and climate change regulations, and the 

reduction in vehicle operating costs which is an outgrowth of some of the technologies 

employed to reduce GHG emissions. Other attributes such as the size or performance 

of a vehicle are assumed to remain unchanged in order to comply with the proposed 

amendments, which is consistent with the constraints on such vehicle attributes 

modeled by Ricardo and in the technology assessment in section III. Additionally, the 

compliance cost estimates explicitly factor in the costs to maintain these attributes at 
Page 221

current levels, e.g. downsized engines have direct injection and turbocharging to 

preserve performance characteristics, which further justifies this modeling assumption.

The CARBITS model is a consumer choice model based on discrete choice modeling 

theory and was developed by the Institute of Transportation Studies at the University of 

California, Davis. The ultimate objective of the modeling effort is to investigate the 

potential fleet mix changes resulting from the proposed amendments which may 

contribute to any criteria pollutant impact. A panel of independent academics reviewed 

the methodology and inputs employed by this model and concluded it to be an 

appropriate tool for this rulemaking. (See Appendix S for additional modeling details.)

Consumer response may manifest itself in different ways. The consumer response to 

the regulations is defined as the difference in the California fleet mix between the 

forecasted baseline and the regulation scenarios. The baseline scenario is a depiction 

of the passenger vehicle fleet in the absence of the proposed emissions regulation. 

While vehicle prices are likely to go up with respect to the regulatory scenarios, the 

operating costs are expected to be lower. As a consequence of the price increase, 

consumers could respond by purchasing fewer new vehicles and holding on to their 

current vehicles a bit longer. Such a shift in vehicle holdings would lead to aging of the 

vehicle fleet. The aging of the fleet could result in older, relatively higher polluting cars 

staying in service longer than they would have remained otherwise. Some may assert 

that this delay in fleet turnover could slow the progress that California is making in 

reducing criteria pollutant emissions from mobile sources. However, under these 

proposed amendments, criteria pollutant standards are concurrently being tightened so 

that the reduced emissions levels of new vehicles may offset any increases from 

prolonged operation of older vehicles. Additionally, the reduction in operating cost could 

make new vehicles more attractive, creating a factor that would increase new vehicle 

sales and turn the fleet over faster. Together, tighter criteria pollutant standards and an 

accelerated fleet turnover would lessen and potentially more than offset the impact of 

any price effects.62 The purpose of the CARBITS model is to quantitatively investigate 

the possible magnitude and direction of such changes.

The focus of this analysis is on the light-duty vehicle fleet, which comprises the majority 

of the on-road fleet and vehicle purchases made by households. While medium-duty 

vehicles are also affected by the proposed regulations, compliance costs for criteria 

pollutant standards are expected to be minimal and only a few vehicle configurations 

are subject to the greenhouse gas standards that would result in any substantial vehicle 

price increases. Therefore, staff believes the emissions effects of consumer response 

related to medium-duty vehicles to be minimal.

2. IMPACTS ON VEHICLE PRICES AND OPERATING COSTS

Based on the cost estimates from sections II.A.4 and III.A.6 of this report, staff 

developed a regulatory scenario to use as inputs to CARBITS in an effort to estimate 

 62 Note additional offsetting criteria pollutant emissions are projected to result from reduced fuel throughput, as 

described in the Environmental Analysis, Appendix B.
Page 222

consumer response to changes in price and operating cost. The latest version of 

CARBITS uses individual vehicle configuration level data. Future baseline vehicle 

prices were first adjusted to account for the increases associated with the National 

Program for MY2012-2016 and the existing ZEV requirements for each of the vehicle 

configurations in the database. The fleet average price increases shown in Table IX-A2-1 were then added to the baseline prices to cover manufacturer compliance costs for 

the entire Advanced Clean Cars package. Table IX-A-2-2 shows the average price 

increase in percentage terms relative to baseline vehicle purchase prices. Prices are 

assumed to decrease at an annual rate of only 2 percent once the standards have fully 

phased in after the 2025 model year due to assumed learning and economies of scale. 

Appendix S shows additional sensitivity analyses for alternative methods for adjusting 

vehicle prices, including at a more detailed vehicle class level. 

Table IX-A-2-1. Advanced Clean Cars, Fleet Average Vehicle Price Changes for MY2015-

2025 Vehicles Relative to Baseline Vehicles (2009 dollars)

Model 

Year

Incremental 

Price

2015 $5

2016 $14

2017 $179

2018 $408

2019 $740

2020 $984

2021 $1,288

2022 $1,525

2023 $1,722

2024 $1,913

2025 $1,910
Page 223

Table IX-A-2-2. Clean Cars, Fleet Average Percentage Change in Vehicle Price for 

MY2015-2025 Vehicles Relative to Baseline Vehicle Prices

Model 

Year

% Price 

Increase

2015 0.0%

2016 0.0%

2017 0.5%

2018 1.1%

2019 2.0%

2020 2.7%

2021 3.6%

2022 4.2%

2023 4.8%

2024 5.3%

2025 5.3%

Section VII presented data on operating cost reductions due to the proposed regulation. 

Due to existing variability in vehicle operating costs, the reductions were applied to 

baseline operating costs on a percentage basis, as shown in Table IX-A-2-3, as 

opposed to assuming all vehicles have the same absolute operating costs that would be 

implied by the standards. Although energy prices are an important component of 

operating costs, these percentage reductions reflect only vehicle technology 

improvements because future fuel prices are kept constant and assumed to be 

unaffected by the proposed amendments. Appendix S shows additional sensitivity 

analyses for alternative methods for adjusting vehicle operating costs.

Table IX-A-2-3. Advanced Clean Cars, Percentage Reduction in Fuel-related Operating 

Cost of MY2015-2025 Vehicles Compared to Baseline Vehicles

Model 

Year

Passenger 

Cars

Light-Duty

Trucks

2015 0% 0%

2016 0% 0%

2017 3% 4%

2018 5% 6%

2019 7% 8%

2020 9% 10%

2021 11% 13%

2022 13% 16%

2023 15% 18%

2024 17% 20%

2025 21% 24%
Page 224

These percentage operating cost savings translate into the following average cents per 

mile savings for a new vehicle, as shown in Table IX-A-2-4. 

Table IX-A-2-4. Advanced Clean Cars, Operating Cost Savings of MY2015-2025 Vehicles 

compared to Baseline Vehicles (Cents Per Mile, 2009 dollars)63

Model 

Year

Passenger 

Cars

Light-Duty

Trucks

2015 0 0

2016 0 0

2017 0.4 0.5

2018 0.6 0.8

2019 0.8 1.1

2020 1.0 1.4

2021 1.3 1.8

2022 1.5 2.1

2023 1.7 2.4

2024 1.9 2.7

2025 2.2 3.2

3. IMPACTS ON VEHICLE SALES, FLEET SIZE, AND AVERAGE AGE

The impacts of the proposed regulation were assessed by forecasting a baseline future 

fleet mix that assumes that, absent the proposed amendments, vehicle prices and 

operating costs change only in response to the existing National Program requirements 

for MY2012-2016. This baseline is then compared to a regulatory scenario that takes 

into account the estimated price and operating cost changes resulting from the 

Advanced Clean Cars program. Figures IX-A-3-1, IX-A-3-2, and IX-A-3-3 show the 

totals and changes in vehicle sales, the size of the fleet, and the average age of the 

fleet resulting from the proposed program relative to the baseline. 

 63 Savings only for first year of ownership as savings will vary with fuel price. See Appendix S for fuel price schedule.
Page 225

Figure IX-A-3-1. New Vehicle Sales for Advanced Clean Cars Program

Figure IX-A-3-2. Total Fleet Size for Advanced Clean Cars Program

 (5,000)

 45,000

 95,000

 145,000

 195,000

 245,000

0

200000

400000

600000

800000

1000000

1200000

1400000

1600000

1800000

2000000

Change in New Sales

Total New Sales

Model Year

ACC New Vehicle Sales Totals Change Relative to Baseline

 (100,000)

 -

 100,000

 200,000

 300,000

 400,000

 500,000

 600,000

 700,000

 800,000

0

5000000

10000000

15000000

20000000

25000000

30000000

Change in Fleet Size

Total Fleet Size

Model Year

ACC Total Fleet Size Change Relative to Baseline
Page 226

Figure IX-A-3-3. Average Vehicle Age for Advanced Clean Cars Program

In the initial years of the regulation there is a negligible decrease in sales due to 

compliance with the criteria pollutant standards while there is no concurrent reduction in 

operating costs resulting from these proposed amendments. However, once the 

greenhouse gas standards begin to phase in during MY2017, the reduced operating 

costs of new vehicles makes them more attractive to consumers and total sales begin to 

increase relative to the baseline. Sales continue to grow over the baseline until the 

standards have been fully phased-in in MY2025. After this point, new vehicles no 

longer offer any significant advantage in operating costs over used vehicles that 

become increasingly available on the market. Thus, the change in sales begins to 

decline, though these levels still represent a relative increase over baseline totals. As a 

result of these sales, the fleet continues to grow slowly with time, making the regulation 

scenario fleet larger in all years compared to the baseline fleet. These sales increases 

also contribute to decreasing the average age of the fleet, implying that households are 

not holding onto their older vehicles longer than they would have in the absence of the 

proposed program.

The assumptions for this analysis do not consider other reductions in ownership costs 

that may be associated with the regulation such as the potential elimination of a mobile 

air conditioning service event through improved refrigerant containment strategies that 

manufacturers may choose to employ. Due to a lack of comprehensive data, however, 

staff assumed no change in maintenance costs for the purpose of this analysis. 

-0.6

-0.5

-0.4

-0.3

-0.2

-0.1

0.0

0.1

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

Change in Average Age

Fleet Average Vehicle Age

Model Year

ACC Average Veh Age Change Relative to Baseline
Page 227

Likewise, the value of potential reductions in refueling time are not included in this 

analysis. Further, the model does not explicitly consider other more intangible vehicle 

attributes associated with the proposed program that consumers may value, such as 

environmental or energy security benefits. 

In addition, the sales projections from CARBITS are based on consumer preferences for 

vehicles that were actually available in the market. For past regulations that resulted in 

relatively transparent modifications to conventional vehicle types, this data limitation did 

not impose a significant restriction. Due to the recent introduction of certain advanced 

vehicle technologies that are still unknown or unfamiliar to vehicle buyers, though, the 

applicability of these same consumer preferences for these vehicle types is uncertain. 

However, the price adjustments reflect the costs associated with complying with the 

entire proposed Advanced Clean Cars program, which conservatively imposes a higher 

cost on the consumers being modeled. Thus, while the sales projections presented 

here technically reflect only the internal combustion or conventional hybrid vehicle 

fleets, staff assumes that other vehicle technologies produced for the ZEV amendments 

will displace some of these sales, though resulting in the same overall light-duty vehicle 

sales levels. 

Finally, these sales projections are generated for the purpose of policy analysis as 

opposed to market forecasting. Vehicle sales volumes and distributions are influenced 

by a host of factors, notably other vehicle attributes, fuel prices and broader economic 

conditions. In this analysis, these other factors are assumed to remain unchanged with 

and without the proposed amendments in order to isolate the effects of the policies. 

Such conditions are unlikely to exist in reality so that actual sales volumes are likely to 

deviate from these projections. Thus, the differential between the two cases serves as 

the most relevant metric for assessing the scale and direction of the impacts. 

4. IMPACTS ON CRITERIA EMISSIONS

Changes in the fleet size and average age would affect criteria emissions. Newer cars 

emit less and will produce steady declines in most vehicle pollutants as new vehicles 

replace existing ones. As discussed previously, the CARBITS results indicate a slight 

acceleration in fleet turnover where the ACC fleet is generally larger but younger than 

the baseline fleet. However newer vehicles tend to be driven more intensively than 

older vehicles, which combined with the rebound effect might increase vehicle miles 

traveled sufficiently to offset the expected emissions reductions from improvements in 

emission controls. ARB staff used the fleet composition generated by CARBITS in a 

modified emissions inventory tool to estimate the changes in criteria pollutant emissions 

shown in Figure IX-A-4-1. 

In all calendar years between 2015 and 2030, all criteria pollutant emissions remain 

lower for the policy case than the baseline even when accounting for any possible 

increases due to changes in consumer purchasing patterns. The results without 

consumer response are analogous to the emissions benefits described in in Section V-
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D.64 These curves (dashed lines, open markers) reflect the changes only from 

improvements in tailpipe emission rates and assume there are no changes in fleet 

composition, though do account for any emissions increases due to the rebound effect. 

An additional change due to a different fleet mix yields the results with consumer 

response (solid line, closed markers). In this case, the distribution of vehicles not only 

includes a greater share of newer vehicles but also more vehicles total to result in a 

larger total fleet. Total emissions are a function of both the vehicle emission rates and 

the number of miles that vehicles are driven. While newer vehicles will have lower 

emission rates, separate from the expected increase in VMT due to the rebound effect 

resulting from the lower operating costs, newer vehicles also tend to be driven more 

intensively in their younger years. Thus, having a greater proportion of newer vehicles 

and a larger total fleet size would generate additional VMT as an artifact of the modeling 

methodology. As a result, consumer responses to new vehicle offerings could reduce 

some of the expected emission reductions of PM2.5 (circles) as a result of an increase 

in VMT. However these same forces could further enhance emission reductions of

ROG (triangles) and have essentially no effect on NOx (squares). For all pollutants the 

Advanced Clean Cars program would continue to produce net benefits when allowing 

for changes in fleet composition.

 64 The CARBITS population reflects only twenty vintages of light-duty vehicles in any calendar year which represents 

a subset of the EMFAC population used for the emission reductions presented in Section V-D. The emissions 

estimates from the two models are therefore not necessarily expected to match exactly, however the CARBITS 

subset covers an overwhelming majority of vehicles in the on-road fleet and their associated VMT. 
Page 229

Figure IX-A-4-1. Advanced Clean Cars, Changes in ROG, NOx, and PM2.5 

Emissions due to Consumer Response (percent)

In the event that total fleetwide VMT is solely a function of the rebound effect, 

renormalizing VMT to account only for those effects but maintaining the changes in fleet 

composition would result in similar changes to the percent reductions without consumer 

response. (See Appendix T for emission calculation methodologies and Appendix S for 

more detailed emission results.)

Overall, staff believes that consumer response to new vehicle offerings would not 

negate any of the positive effects on criteria pollutant emissions that are expected to 

result from the Advanced Clean Cars program, including resultant upstream emission 

reductions (as discussed in section V).

B. ALTERNATIVE APPROACH TO ASSESSING CONSUMER RESPONSE

The CARBITS model considers many factors at a detailed household and vehicle level 

in a bottom-up approach to project changes in fleet composition that may result from the 

Advanced Clean Cars program. Staff also used an alternative approach similar to the 

one used by USEPA for their MY2012-2016 National Program; this method uses an 

aggregate sales response factor, known as the price elasticity of demand, to produce a 

top-down estimate of potential consumer response. The price elasticity of demand is 

0.0%

5.0%

10.0%

15.0%

20.0%

25.0%

30.0%

35.0%

40.0%

45.0%

50.0%

2015201620172018201920202021202220232024202520262027202820292030

Percent Reduction

NOx: w/o Consumer Response

NOx: w/ Consumer Response

ROG: w/o Consumer Response

ROG: w/ Consumer Response

Total PM2.5: w/o Consumer Response

Total PM2.5: w/ Consumer Response
Page 230

defined as the ratio of the percentage change in sales to the percentage change in price 

and is a frequently used measure of consumers’ sensitivity to price. A typical value 

used in the literature and policy analysis is -1, meaning that the percentage decrease in 

new vehicle sales is equal to the percentage increase in vehicle price or vice versa. 

Staff first estimated the percentage change in average new vehicle prices. Assuming 

that all compliance costs are passed onto consumers, this increase will have additional 

financial implications for new vehicle buyers. Higher vehicle prices will result in an 

increase in loan payments for consumers who finance their purchases as well as higher 

insurance premiums and registration fees. However, higher new vehicle prices also 

generally results in higher resale values, which may offset some or all of the increases. 

For all model years, this adjusted incremental vehicle price is less than $1,500. 

Additionally, vehicle owners would also benefit from operating cost savings that 

effectively reduce the cost of vehicle ownership. The adjustments that factor in these 

savings for the first five years of ownership ultimately yield the net price changes shown 

in Table IX-B-1 (see Appendix S for additional details on adjustments). The negative 

values imply that the operating cost savings and higher resale values after five years far 

outweigh ownership costs and any additional compliance costs. 

Table IX-B-1. Advanced Clean Cars Price Elasticity of Demand

MY

Net Adjusted 

Price Change

(2009 dollars)

% Price 

Change

% New Sales 

Change

2015 $0 0.0% 0.0%

2016 $6 0.0% 0.0%

2017 -$268 -0.9% 0.9%

2018 -$341 -1.1% 1.1%

2019 -$434 -1.4% 1.4%

2020 -$536 -1.7% 1.7%

2021 -$701 -2.2% 2.2%

2022 -$833 -2.7% 2.7%

2023 -$965 -3.1% 3.1%

2024 -$1,090 -3.5% 3.5%

2025 -$1,546 -4.9% 4.9%

 

As a result of the net savings, the price of new vehicles declines with time relative to a 

base MY2015 new vehicle. Applying the elasticity value of -1 to the resulting 

percentage change in vehicles prices implies that new vehicle sales would increase by 

0 to 4.9 percent from MY2015 to MY2025 as shown in Table IX-B-1. These percentage 

changes in new vehicle sales are within the same range as those projected by 

CARBITS relative to MY2015 sales levels, as shown in Figure IX-B-1. Sensitivity 

analyses described in Appendix S show that even assuming only three years’ worth of 

operating cost savings would not reduce sales below MY2015 levels. Unlike the 

CARBITS approach, this simplified approach applies only to new vehicle sales and does 
Page 231

not provide any insights into the changes in fleet size or average vehicle age that could 

occur from the regulations. Additionally, this elasticity approach does not take into 

consideration any of the variation in consumer preferences or household characteristics 

or the availability of used vehicles that may influence demand for new vehicles, hence 

why the changes are smoother than those produced by CARBITS.

Figure IX-B-1. Comparison of Approaches to Estimate Percent Change in New Vehicle 

Sales

C. ENERGY COST AND DEMAND FOR NEW VEHICLES

Both of the previous sections suggest that consumers will be willing to trade off the 

future operating savings against the higher upfront cost of new vehicles so that demand 

for new vehicles will remain constant if not increasing slightly. However, given these 

clear private economic benefits, why then have consumers historically not demanded –

and automakers not supplied – vehicles that would supposedly be in their own best 

interests? This issue is often described as an example of the “energy paradox” (Metcalf 

and Hassett 1999; Tietenberg 2009), as one would expect consumers to make these 

seemingly-profitable investments to lower operating costs, and yet they do not.

There are several possible explanations for why consumers might not behave as 

expected. One potential reason is that these consumers are effectively more concerned 

with the upfront costs over the future fuel savings than might otherwise be expected. 

Automobile manufacturers appear to believe that consumers only pay attention to the 

-1%

0%

1%

2%

3%

4%

5%

6%

% Chang in New Vehicle Sales

Model Year

CARBITS Elasticity Method
Page 232

first three years of fuel savings, despite consumers holding on to vehicles for 

substantially longer than that on average (Helfand and Wolverton 2011). In other 

words, consumers may demand a very short payback period or a very high rate of 

return (discount rate) when they invest in vehicles with lower operating costs, but are 

content to accept a longer payback period or a lower rate of return for other 

investments. Indeed, recent literature provides evidence on both sides as to whether 

consumers are currently fully valuing fuel savings (Helfand and Wolverton (2011); 

Allcott and Wozny (2011); and Busse, Knittel, and Zettelmeyer (2011).

Other explanations include imperfect information about fuel economy, other biases in 

decision-making, and capital market imperfections (i.e., the difficulty in obtaining 

sufficient credit to invest in low emission vehicle technology) (Gillingham, Newell, 

Palmer 2009; Allcott and Wozny 2011). For example, consumers may demand shorter 

payback periods because they are loss averse, meaning that the additional investment 

in the new vehicle may not pay back if the owner needs/wants a different vehicle after 

just a few years or the price of fuel suddenly drops (e.g. Metcalf and Hassett 1999). 

Additionally, there is a considerable array of new vehicles available on the market. 

Rather than evaluate each option systematically and individually, consumers may 

succumb to inertia by simply replacing a vehicle with its current incarnation or use other 

shortcuts to whittle down the options, resulting in an “irrational” choice.

Additionally, although payback periods and net monthly fuel expenditures may be 

routine calculations as part of the rulemaking process, consumers may not actually 

perform similar computations. Vehicle prices are determined by a variety of factors. 

Increases may represent additional vehicle content or may simply reflect currency 

exchange rates, commodity prices, or inflation. Even if consumers could distinguish 

between the different causes, vehicles are sold as bundled goods whereby buyers 

cannot pick and choose which attributes to include on their purchase for a clearly 

marked price. Rarely do consumers have the choice between two vehicles that are 

exactly identical except for operating cost and purchase price. Instead, a particular 

vehicle might offer reduced operating cost at a slightly higher initial price while a 

somewhat similar alternative vehicle might provide a separate set of attributes though 

have a slightly lower purchase price and higher operating costs. Selecting the 

alternative vehicle for whatever attribute(s) it offers – cargo room, comfort, safety 

features, towing capacity, Bluetooth connectivity, styling, etc. – does not automatically 

imply an unwillingness to pay for reduced operating costs; simply that the consumer 

exhibits a very high willingness to pay (which could include the ongoing higher operating 

costs) for these other attributes. 

Auto manufacturers operate in a highly competitive market and may themselves be risk 

averse. Despite the wide assortment of vehicle types, attributes, styles, and amenities 

of new vehicle models each year, there still exists a considerable level of substitutability 

between the different offerings. Due to consumers’ apparent ambiguity regarding fuel 

savings, a single manufacturer that attempts to differentiate its products through 

reduced operating costs or lower emissions might be risking market share. Only when 

manufacturers are assured that their competitors are also operating under the same 
Page 233

constraints would they provide these attributes; the proposed program in essence levels 

the playing field. 

Reductions in operating costs might in fact be welcomed by the consumer if such an 

option were available that continued to provide the original desired attribute(s). Most 

consumers do not derive utility from consuming fuel or producing emissions per se, but 

from the services and amenities that are associated with those actions. If those same 

services and amenities can be provided using less fuel and producing fewer emissions, 

consumers would be better off. Indeed, ARB staff believes that compliance with the 

Advanced Clean Cars program will not require manufacturers to reduce other attributes 

from their current levels and the compliance costs explicitly include the costs to 

preserve them. For conventional vehicles, the compliance costs are based on 

technology packages that would be largely invisible to a consumer. The footprint basis 

of the standard and the separate car/truck targets eliminate the incentives for 

manufacturers to reduce the diversity of vehicle sizes and body styles, thus preserving 

consumer choice. So long as the attributes that consumers value most remain 

unchanged as a result of the proposed amendments, the reductions in operating costs 

would improve consumer welfare even if they were not salient enough to be of high 

priority in the selection criterion at the time of purchase.

Here again, if consumers would be willing to purchase such a vehicle, why then do 

manufacturers not provide them? Indeed there are many vehicles that consumers 

might wish to buy that are not available for purchase. In some case, these vehicles 

have yet to be invented or proven feasible concepts. More practically, even for vehicles 

that could be produced using current technology, consumers have highly diverse tastes 

and preferences and manufacturing vehicles to order for each individual buyer is not 

possible. Automakers must therefore attempt to select the suite of attributes that is 

most likely to appeal to the broadest swath of consumers, which might not provide low 

operating costs. Those on the margins must settle for their “next best” option. To the 

degree that these consumers value fuel savings and their next best options would be 

improved along this dimension as a result of the policy, their welfare would be improved.

In the event that some future improvements in vehicles are foregone for the sake of 

regulatory compliance, it is unclear whether this would necessarily reduce consumer 

welfare. Today’s vehicles are markedly better along almost every dimension compared 

to vehicles from decades past. Do today’s vehicle buyers consider themselves to be 

significantly better off than their historic counterparts? To the degree that consumer 

welfare from a new vehicle is derived as it relates to other vehicles on the road, a 

suspension or slower growth rate in further improvements would not represent as great 

a welfare loss as if welfare is derived purely based on the value of the attributes 

themselves.

ARB staff believes that whether or not the valuation of fuel savings played any role in a 

consumer’s purchase decision is a separate issue from that of how the consumer is 

better off as a result of the policy. Consumers who purchase new vehicles will benefit 

from lower operating costs and will now have more money in their pockets. The value 
Page 234

of this money is not diminished if they neither intended nor desired these savings. 

Consumers will continue to purchase those vehicles that maximize their utility. Due to 

the flexible nature of the proposed Advanced Clean Cars program, manufacturers will 

continue to be able to produce a diverse array of vehicles demanded by the market. 

Staff does not believe that compliance will not come at the expense of other attributes, 

as has been the case to date for compliance with MY2009-2011 light-duty vehicle GHG 

standards in California and this assumption has been incorporated into the vehicle cost 

estimates for the proposed amendments. In the event that some consumers might 

experience some welfare loss through a change in their vehicle selection, this would be 

offset by gains from the considerable fuel savings as well as the broader societal and 

environmental benefits generated by the proposed program.

D. MANUFACTURER RESPONSE TO INCREASED VEHICLE PRICES

The majority of the economic analysis has assumed that manufacturers operate in a 

fully competitive market that allows them to pass on the full cost of compliance to 

consumers. While the previous sections largely suggest that consumers would be 

willing to accept such price increases in exchange for the reduced operating costs (in 

the absence of any other changes in vehicle attributes or market conditions), those 

conclusions are primarily based on using vehicle averages and representative 

consumers. In reality both consumers and vehicles vary widely in their characteristics 

and it is not feasible to model the entire array. 

In the event that some consumers would not be willing to accept the full cost of 

compliance, manufacturers would be required to find strategies to maintain a vehicle’s 

appeal or risk losing market share to competitors who may be able to produce a similar 

(or better) vehicle for a lower price. Manufacturers may therefore choose not to pass on 

the full compliance costs in various ways. While an automaker might absorb 

compliance costs of certain vehicles for a limited number of years, this tactic may not be 

a viable long-term solution. However, manufacturers could cross-subsidize vehicles 

within their fleet by increasing vehicle prices of some models beyond their individual 

compliance costs in order to offset some of the increase of other vehicles. Additionally, 

the flexibility mechanisms allowing for banking and trading of credits could allow 

manufacturers to distribute costs over different vehicles as well as over time. Although 

it is possible that costs could fall in the future as a result of learning, economies of 

scale, or innovation, overcompliance in early years while the standard is still phasing-in 

and costs are relatively low could also reduce compliance burdens in later years.

Lastly, it is unlikely that vehicle attributes will remain constant across all dimensions as 

has been assumed in the modeling exercises above. Although useful for policy 

analysis, limiting changes to only operating costs and vehicle prices is not necessarily 

representative of future market offerings. These changes in operating costs and vehicle 

prices are likely to be bundled with other changes in styling, safety, and amenities as 

opposed to being selected “à la carte” by new vehicle buyers. As a result, the relevant 

metric for determining vehicle sales will be the consumer’s willingness to pay for the 

entire bundle and not the single attribute in isolation. 
Page 235

E. EFFECT OF INCREASED FUEL PRICE

Many of the measures that manufacturers will employ to achieve greenhouse gas 

emission reductions will result in reduced vehicle operating costs, due to the fact that 

the vehicles will be more efficient. These operating cost savings in turn feed into the 

staff analysis of the economic impact of the regulation and its cost-effectiveness. 

The dollar value to consumers of a given motor vehicle GHG reduction and any 

associated increase in vehicle efficiency will vary depending on the price of fuel. 

Throughout the staff report analysis the staff has assumed a retail gasoline price around 

$4 per gallon (2009 dollars) between 2015 and 2030 based on the average of the 

values used in the California Energy Commission (CEC) Integrated Energy Policy 

Report (CEC, 2011). Staff’s values are roughly consistent with current California 

conditions. However, given the volatility in fuel prices, staff also replicated relevant 

portions of the analysis using fuel prices that were 30 percent higher to assess the 

extent to which its findings and conclusions depend on fuel price assumptions. 

The primary staff analysis concluded that at a fuel price of $4 per gallon in 2025 the 

GHG reduction technologies would more than pay for themselves over the life of the 

vehicle, and the regulation as a whole would have small but overall positive effects on 

the California economy. As would be expected, if fuel prices were assumed to increase 

to a range of $5-6 per gallon rather than $4 per gallon, net benefits increase both for 

individual consumers and for the State as a whole. Hydrogen and electricity prices are 

assumed to remain constant. The specific impacts are summarized in Table IX-F-1 and 

then discussed below.

Table IX-F-1. Effect of Increased Fuel Price on Economic Impacts of Advanced Clean 

Cars Regulation (2009 dollars)

Fuel Price Assumption

CEC Average 30% Above Avg

Consumer Impacts, MY2025

Net Monthly Difference, New Vehicle $12 savings $28 savings

Net Monthly Difference, Used 

Vehicle

$22 savings $34 savings

California Economy, CY2030

Annualized Savings $11 Billion $14 Billion

Change in Output $14 Billion $18 Billion

Change in Personal Income $6 Billion $8 Billion

Change in Employment 37,000 54,000

Section VII shows the effect of the regulation on monthly expenses for purchasers of 

new vehicles. That analysis looked at the increase in monthly loan payment, assuming 

a 5-year loan that would result from the fleet average increase in new vehicle prices 
Page 236

associated with the fully phased-in regulation. The analysis then factored in the monthly 

decrease in operating expenses associated with the various vehicle technologies. The 

analysis concluded that the average net monthly cost for purchasers of new vehicles 

would increase by about $35 but result in average monthly savings in operating costs 

during that same period of almost $50, for a net savings of $12. As is shown in Table 

IX-F-1, if future fuel prices average over $5 per gallon, then the monthly cash flow is 

more than doubly positive, yielding net monthly savings of almost $30.

For purchasers of used vehicles the staff analysis calculated the increase in loan 

payment assuming a three-year loan. The analysis concluded that purchasers of used 

vehicles would have a monthly net benefit of about $20. If future fuel prices average 

$5.23 per gallon the monthly net benefit will increase to nearly $35.

F. SUMMARY AND CONCLUSIONS

In this section, staff assessed what the consequences would be if one assumes that the 

changes in vehicle attributes do affect sales, in contrast to the economic impact analysis 

previously presented in section VII. Staff analyzed the potential effect of price and 

operating cost changes on sales, fleet size, and fleet age using a consumer choice 

model, CARBITS, developed by researchers at the University of California, Davis. The 

results show that the net effect of increased new vehicle prices and lower operating 

costs is a tendency to increase sales during the period when the stringency of the 

standard is tightening; sales then begin to decline after the standard has fully phased-in, 

though levels remain higher than baseline. This effect had no significant net impact on 

mobile source criteria pollutant emissions in any model year during the phase-in of the 

standards or afterwards through 2030, a result obtained before analyzing any additional 

upstream criteria pollutant emission reductions from decreased fuel throughput. 

Generally, the economic impacts of the proposed Advanced Clean Cars program tend 

to be positive. Staff believes that manufacturers can continue to offer the wide array of 

new vehicles that appeal to a diverse consumer base while also complying with the 

proposed program and preserving or improving consumer welfare. The magnitude of 

positive effects for individual vehicle owners and for the economy as a whole will 

increase if future fuel prices exceed recent historical averages.

X. SUMMARY AND STAFF RECOMMENDATION

A. SUMMARY OF STAFF PROPOSAL

In response to the continued need to reduce emissions from light-duty vehicles in order 

to achieve State and federal ambient air quality standards and provide a healthful 

environment to the citizens of California, staff has presented a number of proposals for 

the Board’s consideration. Considered as a whole, these proposals constitute a 

comprehensive program designed to achieve significant reductions of criteria and 

greenhouse gas emissions and, in conjunction with the proposed modifications to the 
Page 237

Zero-Emission Vehicle and Clean Fuels Outlet programs, also part of this rulemaking, 

lay the groundwork for sustainable transportation in the future. 

In addition, staff has attempted to structure the proposals to make them consistent with 

federal programs currently under development for criteria and GHG emissions while 

retaining those provisions needed to meet California’s unique emission reduction 

requirements.

To summarize, staff has proposed:

• Significant reductions of exhaust and evaporative emissions

• Significant reductions of greenhouse gas emissions well into the future

• Modifications to California certification fuel to better reflect in-use gasoline

• Modifications to the Environmental Performance Label to more accurately reflect 

the emission performance of vehicles and make it more useful to the consumer 

when considering a vehicle purchase

• Minor revisions to the On-Board Diagnostic requirements to assure the 

development of more robust systems 

B. STAFF RECOMMENDATION

For the reasons stated above, staff recommends the Board adopt the proposals set 

forth in this staff report
Page 238

LIST OF ACRONYMS AND ABBREVIATIONS

AC: Air conditioning

ACEff : Air conditioning efficiency

AERO: Aerodynamic drag reduction

A/F: Air/Fuel

AFS: Air fuel ratio sensor

AIS: Air intake system

ARB: California Air Resources Board

ASL: Aggressive shift logic

AT: Automatic transmission

AT-PZEV: Advanced technology partial zero-emission vehicles

ATKCS: Atkinson cycle engine with cam switching

BC: Black carbon

BEV: Battery electric vehicle

BISG: Higher voltage stop-start/belt integrated starter generator

BWC: Butane working capacity

CAFÉ: Corporate Average Fuel Economy

CCP: Coupled cam phasing

CCR: California Code of Regulations

cEGR: Cooled exhaust gas recirculation

CEQA: California Environmental Quality Act

CFC: Chlorofluorocarbon

CFR: Code of Federal Regulations

CGE: Computable general equilibrium

CH4: Methane

CO: Carbon monoxide

CO2: Carbon dioxide

CO2e: CO2- equivalent

cpsi: Cells per square inch

CVT: Continuously variable transmission

CVVL: Continuous variable valve lift

DCP: Dual cam phasing

DCT: Dual clutch or automated shift manual transmissions

DEAC: Cylinder deactivation

DOHC: Dual overhead cam

DRAM: California Department of Finance's Dynamic Revenue Analysis Model

dVA: Digital valve actuation

DVVL: Discrete variable valve lift

E10: Fuel that contains a mix of 10% ethanol and 90% gasoline

E-DRAM: Environmental-DRAM

EFR: Reduction of engine friction losses

EGR: Exhaust-gas recirculation

EHPS: Electro-hydraulic power steering

EMFAC: ARB Emission Factors model (EMFAC2011)

EPS: Electric power steering
Page 239

EV: Electric vehicle

EV(XX): Electric vehicle (XX miles of electric range)

EVOH: Ethylene vinyl alcohol

FCV: Fuel cell electric vehicle

FEL: Family Emission Limit

FTP: Federal Test Procedure

GDI: Gasoline direct injection

GHG: Greenhouse gas

g/mi: Grams per mile

GPF: Gasoline particulate filter

GVWR: Gross vehicle weight rating

GWP: Global Warming Potential

HC: Hydrocarbons

HCFC: Hydrochlorofluorocarbon

HEG: High-efficiency gearbox

HEV: Hybrid electric vehicle

HFC: Hydrofluorocarbon

IACC: Improved Accessories

IATC: Improved automatic transmission controls

ICM: Indirect cost multiplier

IPCC: Intergovernmental Panel on Climate Change

ISO: International Organization for Standardization

Lbs.: Pounds

LCFS: Low carbon fuel standard

LDB: Low-drag brakes

LDT: Light-Duty truck

LDT1: Light-duty truck with a loaded vehicle weight of 0-3750 pounds

LDT2: Light-duty truck with a loaded vehicle weight of 3751 pounds to a gross 

vehicle weight rating of 8500 pounds

LDV: Light-duty vehicle

LEV: Low-emission vehicle

LHD: Light heavy-duty

LNT: Lean NOx trap

LowLeak: Air conditioning low refrigerant leak

LRRT: Low rolling resistance tires

LUB: Low-friction lubricants

LVW Loaded vehicle weight

Mass: Mass reduction

MDPV: Medium-duty passenger vehicle

MDV: Medium-duty vehicle

mg/mi: Milligrams per mile

MHEV: 12-volt micro-hybrid

MMT: Million metric tons

MON: Motor octane number

MTBE: Methyl tertiary butyl ether

MY: Model year
Page 240

NEV: Neighborhood electric vehicle

NF3: Nitrogen Trifluoride

NGV: Natural gas vehicles

NHTSA: National Highway Traffic Safety Administration

NMHC: Non-methane hydrocarbons

NMOG: Non-methane organic gas

NMVOC: Non-methane volatile organic compound

N2O: Nitrous oxide

NOx: Oxides of nitrogen

O3: Ozone

OBD: Onboard diagnostic

OEM: Original equipment manufacturer

OHV: Overhead valve

ORVR: Onboard Refueling Vapor Recovery

PC: Passenger car

PFC: Perfluorocarbon

PFI: Port Fuel Injection

PHEV: Plug-in hybrid electric vehicle

P2HEV: Parallel type hybrid electric vehicle

PM: Particulate matter

PMP: Particulate Measurement Programme

PSHEV: Power-split hybrid electric vehicle

PZEV: Partial zero-emission vehicle, as defined in the “California Exhaust 

Emission Standards and Test Procedures for 2009 and Subsequent Model 

Zero-Emission Vehicles and Hybrid Electric Vehicles, in the Passenger 

Car, Light-Duty Truck and Medium-Duty Vehicle Classes”

REEV(XX): Range-extender electric vehicle (XX miles of electric capability)

ROG: Reactive organic gas

ROLL: Low-rolling-resistance tires

RON: Research octane number

RPE: Retail price equivalent factor

RR: Rolling resistance

RTPA: Regional transportation planning agencies

SAE: Society of Automotive Engineers

SAX: Front or secondary axle disconnect for four-wheel drive systems

SC03: A test procedure designed to determine emissions associated with the use 

of an air conditioner; A/C test procedure

SCR: Selective catalyst reduction

SF6: Sulfur Hexafluoride

SFTP: California Supplemental Federal Test Procedure

SGDI: Stoichiometric gasoline direct-injection technology

SO2: Sulfur dioxide

SPN: Solid particle number 

SULEV: Super-ultra-low-emission vehicle

TAR: Technology Assessment Report

TBDS: Turbocharging and downsizing
Page 241

TDS: Turbocharged downsized

UC: Unified Cycle; a dynamometer driving schedule that is similar to the US06 

test cycle, but with less aggressive speeds and acceleration

ULEV: Ultra-low-emission vehicle

USEPA: United States Environmental Protection Agency

US06: A high-speed, high-acceleration, test procedure designed to measure offcycle emissions

US06 Bag 2: A test procedure comprised of the middle portion of the US06 cycle

V6: Vee-formation six-cylinder

VOC: Volatile organic compounds

VVT: Variable valve timing

ZEV: Zero-emission vehicle

2MHEV: 2-mode hybrid electric vehicle

6MAN: Manual 6-speed transmission

6sp DCT: 6 speed dual clutch transmission
Page 242

REFERENCES

SECTION II

EXHAUST CRITERIA EMISSIONS

Society of Automotive Engineers, 2011. SAE 2011-01—0296, “Development of 

Advanced Zone-Coated Three-Way Catalysts”

Society of Automotive Engineers, 2011. SAE 2011-01-0301, “Investigation of LEV-III 

Aftertreatment Designs”

Society of Automotive Engineers, 2008. SAE 2008-01-0812, “Advanced Washcoat 

Technology for PZEV Application”

Society of Automotive Engineers, 2009. SAE 2009-01-1070, “Low Rhodium Catalyst 

Technology for Gasoline and FFV Applications”

Society of Automotive Engineers, 2009. SAE 2009-01-1068, “Development of Third 

Generation of Gasoline P-ZEV Technology”

Society of Automotive Engineers, 2008. SAE 2008-01-0449, “Development of a Diesel 

Emission Catalyst System for Meeting US SULEV Standards”

Rogozhin, A., M. Gallaher, W. McManus, 2009. Automobile Industry Retail Price 

Equivalent and Indirect Cost Multipliers. Prepared for USEPA. EPA-410-09-003. 

February.

Rogozhin, A., M. Gallaher, G. Helfand, W. McManus, 2010. Using indirect cost 

multipliers to estimate the total cost of adding new technology in the automobile 

industry. International Journal of Production Economics 124. 360–368

US Environmental Protection Agency and National Highway Traffic Safety 

Administration (USEPA and NHTSA), 2011. Draft Joint Technical Support Document: 

Proposed Rulemaking for 2017-2025 Light-Duty Vehicle Greenhouse Gas Emission 

Standards and Corporate Average Fuel Economy Standards. EPA-420-D-11-901. 

November.

SFTP EMISSIONS

California Air Resources Board: Supplemental Federal Test Procedure (SFTP) Test 

Program. Contact – David Eiges, Mobile Source Control Division, California Air 

Resources Board.
Page 243

California Air Resources Board: LEV III PM Test Program. Contact – Sherry Zhang,

Monitoring and Laboratory Division, California Air Resources Board.

California Air Resources Board, 1997: California Air Resources Board, Public Hearing to 

Consider Adoption of New Certification Tests and Standards to Control Exhaust 

Emissions from Aggressive Driving and Air-Conditioner Usage for Passenger Cars, 

Light-Duty Trucks, and Medium-Duty Vehicles Under 8,501 Pounds Gross Vehicle 

Weight Rating, July 1997 (Staff Report). 

http://www.arb.ca.gov/regact/offcycle/staffrep.pdf

California Air Resources Board, 1997: California Air Resources Board, Public Hearing to 

Consider Adoption of New Certification Tests and Standards to Control Exhaust 

Emissions from Aggressive Driving and Air-Conditioner Usage for Passenger Cars, 

Light-Duty Trucks, and Medium-Duty Vehicles Under 8,501 Pounds Gross Vehicle 

Weight Rating, July 1997 (Technical Support 

Document). http://www.arb.ca.gov/regact/offcycle/tsd.pdf. Last accessed August 8, 

2011.

California Air Resources Board, 2006: California Air Resources Board. EMFAC2007. 

Available at: http://www.arb.ca.gov/msei/onroad/latest_version.htm. Last accessed 

August 8, 2011.

EVAPORATIVE EMISSIONS

Clontz, R., M. Elum, P. McCrae, R. Williams. 2007. Effects of Low –Purge Vehicle 

Applications and Ethanol-Containing Fuels on Evaporative Emissions Canister 

Performance. SAE Paper No. 2007-01-1929, pp. 1716-1717

Haskew, H.M., T.F. Liberty, D. McClement. 2006. Fuel Permeation from Automotive 

Systems: E0, E6, E10, E20, and E85 Final Report. CRC report E-65-3, pg. 23

Nulman, M., A. Olejnik, M. Samus, E. Fead, G. Rossi. 2001. Fuel Permeation 

Performance of Polymeric Materials. SAE Paper No. 2001-01-1999, table II

Thomas, E.W. 2009. Fluoroelastomer Compatibility with Bioalcohol Fuels. SAE Paper 

No. 2009-01-0994, pp. 462-472

Williams, R.S., C.R. Clontz. 2001. Impact and Control of Canister Bleed Emissions. 

SAE Paper No. 2001-01-0733, pp. 2-8

ON-BOARD DIAGNOSTICS

Society of Automotive Engineers. SAE J1979-DA “Digital Annex of E/E Diagnostic Test 

Modes”, October 2011.
Page 244

Staff Report: Initial Statement of Reasons (ISOR): Technical Status and Revisions to 

Malfunction and Diagnostic System Requirements for Heavy-Duty Engines (HD OBD) 

and Passenger Cars, Light-Duty Trucks, and Medium-Duty Vehicles and Engines (OBD 

II), April 10, 2009.

SECTION III

CLIMATE CHANGE

IPCC. (2007a). Climate Change 2007: Synthesis Report. Contribution of Working 

Groups I, II and III to the Fourth Assessment Report of the Intergovernmental Panel on 

Climate Change. Cambridge University Press. http://www.ipcc.ch/pdf/assessmentreport/ar4/syr/ar4_syr.pdf

Climate Action Team (CAT 2010) Report to the Governor and Legislature. 

t http://www.energy.ca.gov/2010publications/CAT-1000-2010-004/CAT-1000-2010-

004.pdf

IPCC. (2007b). Technical Summary: Climate Change 2007: The Physical Science 

Basis, Contribution of Working Group I to the Fourth Assessment Report of the 

Intergovernmental Panel on Climate Change. Cambridge University 

Press. https://www.ipcc-wg1.unibe.ch/publications/wg1-ar4/ar4-wg1-ts.pdf

IPCC (2000), Special Report on Emissions Scenarios 

(SRES). http://www.ipcc.ch/pdf/special-reports/spm/sres-en.pdf.

IPCC (2007c), Synthesis report. http://www.ipcc.ch/pdf/assessmentreport/ar4/syr/ar4_syr_spm.pdf

Zhao, C., A. E. Andrews, L. Bianco, J. Eluszkiewicz, A. Hirsch, C. MacDonald, T. 

Nehrkorn, and M. L. Fischer (2009). Atmospheric inverse estimates of methane 

emissions from Central California, J. Geophys. Res., 114, D16302, 

doi:10.1029/2008JD011671.

Ramanathan, V. and G. Carmichael (2008) Global and regional climate changes due to 

black carbon. Nature Geoscience 156, 221-227.

IPCC (2007d), Working Group I: The Physical Science Basis, Chapter 2: Changes in 

Atmospheric Constituents and in Radiative Forcing. http://www.ipcc.ch/pdf/assessmentreport/ar4/wg1/ar4-wg1-chapter2.pdf

Office of Environmental Health Hazard Assessment. Environmental Protection 

Indicators for California (EPIC), 

2009. http://oehha.ca.gov/multimedia/epic/pdf/ClimateChangeIndicatorsApril2009.pdf 
Page 245

Lee, J., S. De Gryze, J. Six. (2009). Effect of Climate Change on Field Crop Production 

in the Central Valley of California. California Energy Commission. CEC-500-2009-041-

F. http://www.energy.ca.gov/2009publications/CEC-500-2009-041/CEC-500-2009-041-

F.pdf

Westerling, A.L., B. P. Bryant, H.K. Preisler, H G. Hidalgo, and T. Das. (2009). Climate 

Change, Growth, and California Wildfire. California Energy Commission. CEC-500-

2009-046-F. http://www.energy.ca.gov/2009publications/CEC-500-2009-046/CEC-500-

2009-046-F.pdf

Vicuna, S.R. Leonardson, M. Hanemann, L. Dale, and J. Dracup. (2008). “Climate 

change impact on high elevation hydropower generation in California's Sierra Nevada: A 

case study in the upper American River.” Climatic Change 87:S123–S137. 

Hadley, O.L., C.E. Corrigan, T.W. Kirchstetter, S.S. Cliff, and V. Ramanathan (2010). 

Measured black carbon deposition on the Sierra Nevada snow pack and implication for 

snow pack retreat, Atmos. Chem. Phys., 10, 7505-7513, doi:10.5194/acp-10-7505. 

The future is now: An update on climate change science impacts and response options 

for California (2008). Publication # CEC-500-2008-

071. http://www.energy.ca.gov/2008publications/CEC-500-2008-071/CEC-500-2008-

071.pdf

GREENHOUSE GAS EMISSIONS

An, F., and DeCicco, J.M., 2007. Trends in Technical Efficiency Trade-Offs for the U.S. 

Light Vehicle Fleet. Society of Automotive Engineers. 2007-01-1325.

California Senate, 2006. SB 1505 Senate Bill; Fuel Hydrogen Alternative Fuel. 

Lowenthal. http://www.leginfo.ca.gov/pub/05-06/bill/sen/sb_1501-

1550/sb_1505_bill_20060930_chaptered.html. Accessed July 14, 2010.

California Air Resources Board (CARB), 2008a. Climate Change Scoping Plan: A 

Framework for Change. December.

California Air Resources Board (CARB), 2008b. Concept Paper: Environmental and 

Energy Standards for Hydrogen Production Senate Bill 

1505. http://www.arb.ca.gov/msprog/hydprod/1505concepts.pdf. April 3.

California Air Resources Board (CARB), 2009a. Detailed California-Modified GREET 

Pathway for California Average and Marginal Electricity. Version 2.1. February 27.

California Air Resources Board (CARB), 2009b. Detailed California Modified GREET 

Pathway for Compressed Gaseous Hydrogen from North American Natural Gas. 
Page 246

Version 2.1. February 27.

California Air Resources Board (CARB), 2010b. Proposed Regulation for a California 

Renewable Electricity Standard Staff Report: Initial Statement of Reasons. Appendix D. 

Supporting Documentation for the Environmental Analysis. June.

California Energy Commission (CEC), 2011. Transportation Fuel Price and Demand 

Forecasts: Inputs and Methods for the 2011 Integrated Energy Policy Report - FINAL 

STAFF REPORT. Publication # CEC-600-2011-

001. http://www.energy.ca.gov/2011publications/CEC-600-2011-001/CEC-600-2011-

001.PDF

Energy and Environmental Economics, Inc., (EEE), 2010a. Greenhouse Gas Modeling 

of California’s Electricity Sector to 2020: Updated Results of the GHG Calculator 

Version 3b Update. Prepared for California Public Utilities Commission. October.

Energy and Environmental Economics, Inc., (EEE), 2010b. GHG Calculator Version 

3c. http://www.ethree.com/documents/GHG%20update/GHG%20 

Calculator%20version%203c_Oct2010.zip. October.

FEV, 2011. Light-Duty Technology Cost Analysis Power-split and P2 HEV Case 

Studies. Prepared for USEPA. 

FEV, 2010. Light-Duty Technology Cost Analysis: Report on Additional Case Studies. 

Prepared for USEPA. EPA-420-R-10-010. April.

FEV, 2009. Light-Duty Technology Cost Analysis Pilot Study. Prepared for USEPA. 

EPA-420-R-09-020. December.

Lee, S., B. Lee, H. Zheng, C. Sze, L. Quinones, and J. Sanchez, 2011. Development of 

Greenhouse Gas Emissions Model for 2014-2017 Heavy- and Medium-Duty Vehicle 

Compliance, SAE 2011 Commercial Vehicle Engineering Congress, Chicago, 

September 2011, SAE Paper 2011-01-2188.

Lotus Engineering, Inc., 2010, An Assessment of Mass reduction Opportunities for a 

2017 – 2020 Model Year Vehicle Program”, Rev 006A.

Lutsey, N., 2010. Review of Technical Literature and Trends Related to Automobile 

Mass-Reduction Technology. Institute of Transportation Studies, University of 

California, Davis. UCD-ITS-RR-10-10.

Lutsey, N. and D. Sperling, 2005. Energy efficiency, fuel economy, and policy 

implications. Transportation Research Record. 1941: 8-17.

Lutsey, N. and D. Sperling, 2010. Toward integration of vehicle and fuel regulation: 

California case study. Transportation Research Record. 2191: 100-110.
Page 247

National Research Council (NRC). 2011. Assessment of Fuel Economy Technologies 

for Light-Duty Vehicles. Washington D.C.

Nelson, P.A., K.G. Gallagher, I. Bloom, and D.W. Dees, 2011. Modeling the 

Performance and Cost of Lithium-Ion Batteries for Electric-Drive Vehicles. Final Report 

Submitted to the Environmental Protection Agency. Argonne National Laboratory. July 

15. 

Northeast States Center for a Clean Air Future (NESCCAF), 2004. Reducing 

Greenhouse Gas Emissions from Light-Duty Motor Vehicles. September 2004.

Ricardo, Inc., 2011. Computer Simulation of Light-Duty Vehicle Technologies for 

Greenhouse Gas Emission Reduction in the 2020-2025 Timeframe. Prepared for U.S. 

Environmental Protection Agency.

Rogozhin, A., M. Gallaher, W. McManus, 2009. Automobile Industry Retail Price 

Equivalent and Indirect Cost Multipliers. Prepared for USEPA. EPA-410-09-003. 

February.

Rogozhin, A., M. Gallaher, G. Helfand, W. McManus, 2010. Using indirect cost 

multipliers to estimate the total cost of adding new technology in the automobile 

industry. International Journal of Production Economics 124. 360–368

Santini, D., K. Gallagher, and P. Nelson, 2010. Modeling of Manufacturing Costs of 

Lithium-Ion Batteries for HEVs, PHEVs, and EVs. Electric Vehicle Symposium 

(EVS25). Shenzhen, China. November 5-9. 

Society of Automotive Engineers, Cancelled 2002. J1634: Electric Vehicle Energy 

Consumption and Range Test Procedure. http://standards.sae.org/j1634_200210 (and 

see http://standards.sae.org/wip/j1634).

Society of Automotive Engineers, 2008. J2727: HFC-134a Mobile Air Conditioning 

System Refrigerant Emission Chart. http://standards.sae.org/j2727_200808.

Society of Automotive Engineers, 2010. J1711: Recommended Practice for Measuring 

the Exhaust Emissions and Fuel Economy of Hybrid-Electric Vehicles, Including Plug-in 

Hybrid Vehicles. http://standards.sae.org/j1711_201006.

Society of Automotive Engineers, 2010. J2841: Utility Factor Definitions for Plug-In 

Hybrid Electric Vehicles Using Travel Survey 

Data. http://standards.sae.org/j2841_201009.

US Environmental Protection Agency (USEPA), 2011. Peer Review of the Greenhouse 

gas Emissions Model (GEM) and EPA's Response to Comments, Docket # EPA-HQOAR-2010-0162-3418, Publication Number: EPA-420-R-11-007. July.
Page 248

U.S. Environmental Protection Agency and National Highway Traffic Safety 

Administration (USEPA and NHTSA), 2010. Light-Duty Vehicle Greenhouse Gas 

Emission Standards and Corporate Average Fuel Economy Standards; Final Rule.

U.S. Environmental Protection Agency (USEPA), 2010. Light-duty automotive 

technology, carbon dioxide emissions, and fuel economy trends: 1975 Through 2010. 

EPA420-R-10-023.

U.S. Environmental Protection Agency (USEPA), National Highway Traffic Safety 

Administration (NHTSA), and California Air Resources Board (CARB), 2010. Interim 

Technical Assessment Report: Light-Duty Vehicle Greenhouse Gas Emission 

Standards and Corporate Average Fuel Economy Standards in Model Years 2017-

2025. http://www.epa.gov/otaq/climate/regulations/ldv-ghg-tar.pdf. September.

U.S. Environmental Protection Agency and National Highway Traffic Safety 

Administration (US EPA and NHTSA), 2011a. 2017–2025 Model Year Light-Duty 

Vehicle GHG Emissions and CAFE Standards: Supplemental Notice of Intent. Federal 

Register. Vol. 76, No. 153. August 9.

US Environmental Protection Agency and National Highway Traffic Safety 

Administration (USEPA and NHTSA), 2011b. 2017 and Later Model Year Light-Duty 

Vehicle Greenhouse Gas Emissions and Corporate Average Fuel Economy Standards; 

Proposed Rule. Prepublication Draft. November 16. 

US Environmental Protection Agency and National Highway Traffic Safety 

Administration (USEPA and NHTSA), 2011c. Draft Joint Technical Support Document: 

Proposed Rulemaking for 2017-2025 Light-Duty Vehicle Greenhouse Gas Emission 

Standards and Corporate Average Fuel Economy Standards. EPA-420-D-11-901. 

November.

Yeh, S., N. Lutsey, N. Parker, 2009. Assessment of technologies to meet a low carbon 

fuel standard. Environmental Science & Technology 43(18): 6907-6914. 

SECTION IV

U.S. Energy Information Administration. “Refiner Motor Gasoline Sales Volumes.” 

Petroleum & Other Liquids. 1 August 2011. Online 8 August 

2011. http://www.eia.doe.gov/dnav/pet/pet_cons_refmg_c_SCA_EPMM_mgalpd_m.htm
Page 249

SECTION V

FUEL CYCLE EMISSIONS

Argonne National Laboratory (ANL), 2007. GREET 2.7 Vehicle Cycle 

Model. http://greet.es.anl.gov/greet_2_series.

California Air Resources Board (CARB), 2009. CA-GREET 

1.8b. http://www.arb.ca.gov/fuels/lcfs/lcfs.htm. December.

Energy and Environmental Economics, Inc., (EEE), 2010a. Greenhouse Gas Modeling 

of California’s Electricity Sector to 2020: Updated Results of the GHG Calculator 

Version 3b Update. Prepared for California Public Utilities Commission. October.

Energy and Environmental Economics, Inc., (EEE), 2010b. GHG Calculator Version 

3c. http://www.ethree.com/documents/GHG%20update/GHG%20 

Calculator%20version%203c_Oct2010.zip. October.

Kim,H-J, C. McMillan, G.A. Keoleian, and S.J. Skerlos, 2010. Greenhouse Gas 

Emissions Payback for Lightweighted Vehicles Using Aluminum and High-Strength 

Steel. Journal of Industrial Ecology 14(6): 929-946.

Patterson, J., M. Alexander, and A. Gurr, 2011. Preparing for a Life Cycle CO2

Measure. Prepared for Low-Carbon Vehicle Partnership. May 20.

REBOUND EFFECT 

Hymel, K., K. Small, and K. Van Dender (2010) Induced Demand and Rebound Effects 

in Road Transport, Transportation Research B, 44(10): 1220-1241.

HEALTH EFFECTS

CARB 2010 Appendix J of Staff Report, Initial Statement of Reasons for Proposed 

Rulemaking, “Proposed Amendments to the Truck and Bus Regulation, the Drayage 

Truck Regulation and the Tractor-Trailer Greenhouse Gas Regulation” (2010)

CDOF. California Department of Finance population projection web site. Available 

at: http://www.dof.ca.gov/research/demographic/reports/view.php

(File: Compiled Health Tables ACC 2dec11.xls)

CDPH. California Department of Public Health statistics web site. Available 

at: http://www.cdph.ca.gov/data/statistics/Pages/default.aspx

(File: Compiled Health Tables ACC 2dec11.xls)
Page 250

Fann N, Fulcher CM and Hubbell BJ. 2009. The influence of location, source, and 

emission type in estimates of the human health benefits of reducing a ton of air pollution 

Air Quality. Atmosphere & Health. 2:169-176.

Fotheringham S and Rogerson P, editors. 1994. Spatial Analysis and GIS. London. 

Taylor and Francis. Chapter 7, pp 121-145.

Goodchild M and Lam N. 1980. Areal interpolation: a variant of the traditional spatial 

problem. Geo-processing, 1: 297-312.

Goodin WR, McRae GJ and Seinfeld JH. 1979. A Comparison of Interpolation Methods 

for Sparse Data: Application to Wind and Concentration Fields. J Applied Meteor. 

18:761-771.

Krewski D, Jerrett M, Burnett RT, Ma R, Hughes E, Shi Y, Turner MC, Pope CA III, 

Thurston G, Calle EE and Thun MJ. 2009. Extended follow-up and spatial analysis of 

the American Cancer Society study linking particulate air pollution and mortality. HEI 

Research Report, 140, Health Effects Institute, Boston, MA.

Shepard D. 1968. A two-dimensional interpolation function for irregularly-spaced 

data. Proceedings of the 1968 ACM National Conference. Pp. 517–524.

US Census Bureau. American Fact Finder web site. Available 

at: http://factfinder.census.gov/home/saff/main.html?_lang=en

US Census Bureau. American Fact Finder web site. Available at:

http://factfinder.census.gov/home/saff/main.html?_lang=en

(File: Compiled Health Tables ACC 2dec11.xls)

US EPA. 2010. Quantitative Health Risk Assessment for Particulate Matter Available 

at: http://www.epa.gov/ttn/naaqs/standards/pm/data/PM_RA_FINAL_June_2010.pdf

SECTION IX

ECONOMIC ANALYSIS

Allcott, H. and N. Wozny (2011) Gasoline Prices, Fuel Economy, and the Energy 

Paradox, MIT Working Paper.

Busse, Meghan, Christopher Knittel, and Florian Zettelmeyer (2011) Pain at the Pump: 

How Gasoline Prices Affect Automobile Purchasing, NBER Working Paper #15590.

California Energy Commission (2011) Transportation Energy Forecasts and Analyses 

for the 2011 Integrated Energy Policy Report, Draft Staff Report. CEC-600-2011-007-

SD.
Page 251

Gillingham, K., R. Newell, and K. Palmer (2009) Energy Efficiency Economics and 

Policy, Annual Review of Resource Economics, 1: 597-619

Helfand, G. and A. Wolverton (2011) Evaluating the Consumer Response to Fuel 

Economy: A Review of the Literature, International Review of Environmental and 

Resource Economics, 5(2): 103-146 

Metcalf, G., and K. Hassett (1999) Measuring the Energy Savings From Home 

Improvement Investments: Evidence From Monthly Billing Data, The Review of 

Economics and Statistics, 81(3): 516-528.

Tietenberg, T. (2009). “Reflections – Energy Efficiency Policy: Pipe Dream or Pipeline 

to the Future?” Review of Environmental Economics and Policy 3 (2): 304 -320.
Page 252

APPENDICES

APPENDIX A: Proposed Regulation Order

APPENDIX B: Environmental Analysis for the Advanced Clean Cars Program

APPENDIX C: Proposed Amendments to the "California Exhaust Emission Standards 

and Test Procedures for 2001 and Subsequent Model Passenger Cars, LightDuty Trucks, and Medium-Duty Vehicles" 

APPENDIX D: Proposed New "California 2015 and Subsequent Model Criteria Pollutant 

Exhaust Emission Standards and Test Procedures and 2017 and Subsequent 

Model Greenhouse Gas Exhaust Emission Standards and Test Procedures for 

Passenger Cars, Light-Duty Trucks, and Medium-Duty Vehicles"

APPENDIX E: Proposed Amendments to the " California Non-Methane Organic Gas 

Test Procedures"

APPENDIX F: Proposed Amendments to the "California Evaporative Emission 

Standards and Test Procedures for 2001 and Subsequent Model Motor Vehicles"

APPENDIX G: Proposed Amendments to the "California Refueling Emission Standards 

and Test Procedures for 2001 and Subsequent Model Motor Vehicles"

APPENDIX H: Proposed Amendments to the "Specifications for Fill Pipes and Openings 

of Motor Vehicle Fuel Tanks"

APPENDIX I: Proposed New "Specifications for Fill Pipes and Openings of 2015 and 

Subsequent Motor Vehicle Fuel Tanks"

APPENDIX J: Proposed Amendments to the "California Exhaust Emission Standards 

and Test Procedures for 2004 and Subsequent Model Heavy-Duty Otto-Cycle 

Engines"

APPENDIX K: Proposed Amendments to the "California Exhaust Emission Standards 

and Test Procedures for 2004 and Subsequent Model Heavy-Duty Diesel 

Engines and Vehicles"

APPENDIX L: Proposed Amendments to the "California Environmental Performance 

Label Specifications for 2009 and Subsequent Model Year Passenger Cars, 

Light-Duty Trucks, and Medium-Duty Passenger Vehicles "

APPENDIX M: Proposed Amendments to the "California Test Procedure for Evaluating 

Substitute Fuels and New Clean Fuels "

APPENDIX N: Proposed New "California Test Procedure for Evaluating Substitute Fuels 

and New Clean Fuels in 2015 and Subsequent Years"

APPENDIX O: Technical Support Document - Development of Supplemental Federal 

Test Procedures Standards

APPENDIX P: Technical Support Document - Development of PM Standards

APPENDIX Q: Technical Support Document - Development of LEV III Greenhouse Gas 

Standards

APPENDIX R: Technical Support Document - GHG Non-Test Cycle Provisions

APPENDIX S: Technical Support Document - Economic Analysis

APPENDIX T: Technical Support Document - Emissions Benefit Analysis

APPENDIX U: Technical Support Document - Climate Change Impacts of Black Carbon 

Particles