Appendix N 

Analysis of Regulatory Alternatives 

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Analysis of Regulatory Alternatives 

Throughout the regulatory development process, staff considered many different 

regulatory structures and elements. Some of these alternatives were developed 

internally to assess the benefits of regulatory options, and some were developed by 

stakeholder groups as counter-proposals. This document compares each alternative 

regulatory approach against the proposed regulation. 

A. ARB January 2008 Regulatory Proposal 

In January 2008, ARB staff proposed a regulatory structure that would have required 

truck and bus operators to replace pre-2007 trucks with 2007 engine model year 

equivalent vehicles between 2010 and 2013, and pre-2010 trucks and buses with 2010 

engine model year equivalent vehicles between 2017 and 2021. The January 2008

proposal was designed on the modernization program envisioned in the 2007 Statewide 

Implementation Plan, and would have required all trucks and buses operating in 

California to meet 2010 emission standards by 2023. 

Figures 1 and 2 compare emissions benefits that would have been generated by the 

January 2008 proposal, and compared those to emissions benefits that would have 

been generated by the proposed regulatory proposal. In this case we did not model the 

phase-in of the January proposal, and instead modeled a simple case that assumed 

compliance by 2014 and 2020. Figure 1 shows in 2014 and 2020 the January proposal

would have generated more NOx reductions than the proposed rule. Figure 2 shows 

that the January proposal would have achieved essentially the same PM2.5 emissions 

reductions as the proposed regulation. 
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Figure 1: NOx Emissions: January 2008 Proposal vs. Current ARB Proposal 

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2010 2012 2014 2016 2018 2020 2022 2024

NOx Tons per Day

Baseline ARB Proposal MY 07 by 2014, MY14 by 2020 for pre-2010

Figure 2: PM2.5 Emissions: January 2008 Proposal vs. Current ARB Proposal 

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2010 2012 2014 2016 2018 2020 2022 2024

PM2.5 Tons per Day

Baseline ARB Proposal MY 07 by 2014, MY14 by 2020 for pre-2010
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B. Agricultural Stakeholders’ Proposal 

A group of more than 70 agricultural stakeholder groups submitted several alternative 

regulatory proposals to ARB. The most recent version was submitted to ARB staff on 

July 15, 2008. The alternative proposal contained several different regulatory structures 

and elements including elevated mileage exemption thresholds, exemptions for trucks 

used in field operations and to the point of first processing, a slower phase-in for BACT 

compliance than the ARB Rule, and truck trade down concepts. 

To assess the impact of the agricultural stakeholders’ proposal if applied to all trucks 

operating in California, we focused on the two most important elements of the proposal. 

The first element we focused on, as shown in Table 1, is the mileage exemption 

thresholds. Under this concept trucks and buses driving fewer than the mileage 

threshold would be exempt from retrofit or replacement requirements. The second 

element we focused on was the delayed BACT schedule, as shown in Table 2. 

Table 1: Mileage exemption proposed by agricultural stakeholders 

Model Year-Engine Mileage Exemption Threshold* 

Pre-1996 15,000 

1996 – 2005 20,000 

2005 and newer 25,000 

* Note - Based upon three year average 

Table 2: Compliance schedule proposed by agricultural stakeholders 

Emissions calculations were developed in July and as a result are based on the June 

2008 draft Statewide inventory, which is slightly higher than the final inventory 

developed to analyze the proposed regulation. Figure 3 and Figure 4 compare NOx 

and PM2.5 emissions respectively for the June 2008 baseline, the current proposed 

regulation, and the agricultural stakeholders’ proposed approach. Results show that 

due to enhanced mileage exemptions and delayed BACT implementation the 

stakeholders’ proposal would achieve much fewer benefits than the ARB proposal. In 

particular, the stakeholders’ proposed approach would reduce NOx emissions benefits 

in 2014 and 2017 by more than 75% relative to the proposed regulation, and would not 

meet SIP targets. 

Engine Model-Years Compliance Deadline, 

as of December 31

Pre-1990 2012 

1991-1994 2013 

1995-1998 2015 

1999-2004 2017 

2005-2007 2019 

2008 2021 

2009 2022 
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Figure 3: Statewide NOx Emissions: Agricultural Stakeholders’ Proposal vs. 

ARB Proposed Approach (June 2008 Draft Inventory)

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2010 2012 2014 2016 2018 2020 2022 2024

NOx Tons per Day

Baseline ARB Proposal Agricultural proposal to all fleets

Figure 4: Statewide PM2.5 Emissions: Agricultural Stakeholders’ Proposal vs. 

ARB Proposed Approach (June 2008 Draft Inventory)

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2010 2012 2014 2016 2018 2020 2022 2024

PM2.5 Tons per Day

Baseline ARB Proposal Agricultural proposal applies to all fleets
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C. Alternatives proposed by DTCC 

Driving Toward A Cleaner California (DTCC) is a coalition representing the California 

Chamber of Commerce, the California Trucking Association, the Western States 

Petroleum Association, the Construction Industry Air Quality Coalition, and a number of 

other business and community organizations. In a letter dated August 21, 2008, DTCC 

proposed an alternative to the ARB proposed rule. The DTCC alternative contained 

many different regulatory elements and approaches, which differed significantly from the 

ARB proposed regulation. These elements included mileage thresholds, delayed BACT 

implementation relative to the ARB proposal, more lenient fleet average and percent 

limit targets, special provisions for small fleets using a trade down approach, 

certifications for compliance, special provisions for single-unit trucks, and other 

approaches. 

To assess the impact of the DTCC proposal we modeled the four most important 

elements of the proposal: mileage exemptions, dedicated use and single-unit truck 

provisions, small fleet provisions, and revised BACT/fleet average/percent limit targets. 

These four elements were chosen for analysis because they would most significantly 

reduce the benefits of the proposed regulation. Each of these four elements is 

described specifically below: 

1. Mileage Exemption Provisions 

For most fleets, the ARB proposed regulation provides mileage exemptions for a variety 

of low-use vehicles but does not provide any exemptions for trucks driving more than 

7,500 miles per year. Under the DTCC proposal, trucks driving less than 30,000 miles 

per year would be separated into three groups: 

a) 15,000 – 30,000 miles per year 

By the end of 2010, all trucks and buses driving between 15,000 and 30,000 miles per 

year would need to emit at less than or equal to a 2004 engine emission rate either 

through vehicle retrofit or replacement. By the end of 2020, these same vehicles would 

need to upgrade to meet 2010 engine emission rates. 

b) 7,500 – 15,000 miles per year 

By the end of 2010, all trucks and buses would be required to meet a minimum standard 

of a 1994 engine equivalent NOx emission rate and be equipped with a level 3 PM 

control device or better. By the end of 2020, these vehicles would be required to emit at 

less than or equal to a 2007 engine emission rate. 

c) Under 7,500 miles per year 

By the end of 2010 all trucks and buses would be equipped with a level 3 PM control 

device, and by the end of 2020 these vehicles would be required to meet a minimum 

standard of a 2004 engine equivalent emission rate. 
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2. Dedicated Use and/or Single-Unit Vehicle Requirements 

Under the DTCC proposal, all single-unit trucks and dedicated use tractors would be 

required by the end of 2012 to at a minimum meet a 1994 engine emission rate with a 

level 3 PM control device and a 25% NOx control device. By the end of 2020 these 

vehicles would be required to at a minimum meet 2007 engine emission rates. 

3. Small Fleet Provisions (Fleets of 3 or Fewer Trucks) 

Under the DTCC proposal small fleets would have additional time to meet a more 

lenient emission standard than proposed by ARB staff. Owner operators, and first 

trucks in two or three truck fleets would be required to meet at a minimum 2004 engine 

emission rates by the end of 2012. Second trucks in a two or three truck fleet would be 

required to meet the minimum 2004 engine emission rate requirements by the end of 

2015. Third trucks in three truck fleets would be required to meet the minimum 2004 

engine equivalent emission rate by the end of 2016. All of these trucks would be 

required to meet 2010 engine emission rates by the end of 2020. 

4. Fleet Average / Percent Limit / BACT Provisions 

Under both the ARB and DTCC proposals, large fleets would be given the option of 

complying with fleet average, turnover percentage limitations, or BACT provisions. 

Under the DTCC proposal, compliance would be delayed by several years, a 

comparison to the ARB Proposal is shown in Table 3, Table 4, and Table 5 (Reprinted 

from DTCC Letter Dated 8/21/08). 

Table 3: DTCC BACT Schedule (shaded where different from ARB proposal) 

Compliance 

Deadline, 

as of December 31

Engine Model-Years BACT Requirements

2010 Pre-1994 PM BACT 

2011 1994 - 1997 PM BACT

2012 1998 - 2003 PM BACT

2013 2004 - 2006 PM BACT

2014 Pre - 1994 NOx and PM BACT

2015 1994 - 1997 NOx and PM BACT

2016 1998 - 2003 NOx and PM BACT

2017 2004 - 2006 NOX and PM BACT

2018 NA NA

2019 NA NA

2020 2007 NOx and PM BACT

2021 2008 NOx and PM BACT

2022 2009 NOx and PM BACT
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Table 4: DTCC Percent Limits (shaded where different from ARB proposal) 

Compliance Deadline, Percentage of Total Fleet Complying with BACT

as of December 31 PM BACT NOx BACT

2010 25% NA 

2011 25% NA 

2012 50% 25%

2013 100% 25% 

2014 100% 50%

2015 100% 50% 

2016 100% 75%

2017 100% 75%

2018 100% 80%

2019 100% 90%

2020 100% 90%

2021 100% 90%

2022 100% 100%

Table 5: DTCC Fleet Average Proposal (NOx Targets) (shaded where different 

from ARB proposal) 

Compliance Deadline, Fleet NOx Targets for each compliance deadline

as of December 31 MHD HHD

2012 8.5 14.4

2013 8.5 14.4 

2014 5.8 9.8

2015 5.8 9.8 

2016 4.6 7.8

2017 4.6 7.8

2018 4.0 6.0

2019 4.0 6.0

2020 3.2 3.0

2021 1.6 3.0

2022 0.8 1.6

5. DTCC Emissions Impacts 

To assess emissions impacts of the DTCC proposal, we first ran the complete scenario 

covering the four main provisions of the proposal together. Results, as displayed in 

Figure 5 and Figure 6, show that prior to 2021, the DTCC proposal falls far short of the 

reductions required by the SIP, providing roughly half of the emissions benefits provided 

by the ARB proposal. The delayed implementation to cleaner technologies that is 

embodied by the DTCC proposal would, if implemented, result in California not meeting 

the emissions reductions necessary to meet air quality attainment goals in 2014 for the 

South Coast and 2017 for the San Joaquin Valley. 
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Figure 5: Statewide NOx Emissions: DTCC vs. ARB Proposed Approach

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2010 2012 2014 2016 2018 2020 2022 2024

NOx Tons per Day

Baseline ARB proposal DTCC proposal

Figure 6: Statewide PM2.5 Emissions: DTCC vs. ARB Proposed Approach

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2010 2012 2014 2016 2018 2020 2022 2024

PM2.5 Tons per Day

Baseline ARB proposal DTCC proposal

In addition to running the four primary elements of the DTCC proposal at the same time, 

we also looked at the impact individual provisions would have on select groups of 

trucks, and how those provisions would compare to the ARB proposed regulation. 
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a) Provisions Applied to Trucks in Large Fleets (Four or More Trucks) 

Under the DTCC proposal, large fleets would be subject to both mileage limitations and 

fleet average / BACT / BACT percentage limits requirements. To assess the impact of 

these provisions on large fleets, we first applied mileage thresholds to all large fleet 

trucks, and then layered mileage exemptions and fleet average / BACT / BACT 

percentage limits to large fleets excluding single unit trucks. In the second analysis, we 

excluded single unit trucks because they would be covered under separate provisions of 

the DTCC proposal. 

First, we applied mileage exemption requirements to large fleet trucks only in order to 

isolate the impact elevated mileage exemptions proposed by DTCC would have in 

reducing emissions benefits relative to the proposed regulation. Figure 7 and Figure 8 

compare NOx and PM2.5 respectively to this category. Results show that in general 

NOx and PM2.5 benefits would be reduced by 25%, although this fraction varies 

somewhat by calendar year. 

Figure 7: Statewide NOx Emissions for Large Truck Fleets: DTCC Mileage 

Exemptions vs. ARB Proposed Regulation

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2010 2012 2014 2016 2018 2020 2022 2024

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Baseline ARB proposal DTCC mileage exempt
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Figure 8: Statewide PM2.5 Emissions for Large truck Fleets: DTCC Mileage 

Exemptions vs. ARB Proposed Regulation. 

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PM2.5 Tons per Day

Baseline ARB proposal DTCC mileage exempt

Next, we removed single unit trucks from the analysis, and applied fleet average / BACT 

/ BACT percentage limits requirements in the DTCC proposal, as shown in Figure 9 and 

Figure 10. Results show that NOx benefits in 2014 would be reduced by 42% due to 

mileage provisions alone, and by 55% due to mileage provisions and fleet average / 

BACT / BACT percentage limit requirements. In 2014 PM2.5 benefits would be reduced 

by 16% due to mileage exemptions under the DTCC proposal, and by 21% due to the 

combination of mileage exemptions and fleet average / BACT / BACT percentage limit 

requirements in the DTCC proposal. 
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Figure 9: Statewide NOx Emissions for Large Truck Fleets: DTCC Mileage 

Exemptions and Fleet Average / BACT / BACT Percentage Limits vs. ARB 

Proposed Regulation

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2010 2012 2014 2016 2018 2020 2022 2024

NOx Tons per Day

Baseline ARB proposal DTCC proposal

Figure 10: Statewide PM2.5 Emissions for Large Truck Fleets: DTCC Mileage 

Exemptions and Fleet Average / BACT / BACT Percentage Limits vs. ARB 

Proposed Regulation

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2010 2012 2014 2016 2018 2020 2022 2024

PM2.5 Tons per Day

Baseline ARB proposal DTCC proposal
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b) Single-Unit Truck Requirements 

As discussed above, DTCC proposed specific compliance requirements for dedicated 

use and single-unit trucks. To evaluate this option, we modeled the DTCC proposal as 

it would have applied to single-unit trucks. This evaluation accounts for the single-unit 

truck provisions, as well as mileage provisions that apply to single-unit trucks, and small 

fleet provisions that apply to single unit trucks under both the DTCC and ARB 

proposals. Results shown in Figure 11 and Figure 12 for NOx and PM2.5 respectively 

show that the DTCC proposal would achieve less than half of the benefits in this 

category than would be achieved by the ARB proposal. 

Figure 11: Statewide NOx Emissions for Single-Unit Trucks: DTCC Provisions 

vs. ARB Proposed Regulation

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2010 2012 2014 2016 2018 2020 2022 2024

NOx Tons per Day

Baseline ARB proposal DTCC proposal
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Figure 12: Statewide PM2.5 Emissions for Single-Unit Trucks: DTCC Provisions 

vs. ARB Proposed Regulation

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PM2.5 Tons per Day

Baseline ARB proposal DTCC proposal

c) Provisions Applied to Small Fleets 

As described above, under the DTCC proposal, small fleet requirements are less 

stringent than in the proposed ARB regulation. The net impact of the DTCC small fleet 

provisions is to reduce emissions benefits until 2021, when those vehicles would meet 

the emissions levels envisioned by the proposed ARB regulation. In particular, the loss 

in PM benefits in this category under the DTCC proposal would be large; and small 

fleets account for roughly a third of emissions in the inventory. Results are shown in 

Figure 13 and Figure 14. 
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Figure 13: Statewide NOx Emissions for Small Fleet Trucks: DTCC Provisions 

vs. ARB Proposed Regulation

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2010 2012 2014 2016 2018 2020 2022 2024

NOx Tons per Day

Baseline ARB proposal DTCC proposal

Figure 14: Statewide PM2.5 Emissions for Small Fleet Trucks: DTCC Provisions 

vs. ARB Proposed Regulation

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2010 2012 2014 2016 2018 2020 2022 2024

PM2.5 Tons per Day

Baseline ARB proposal DTCC proposal