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United States Air and Radiation EPA420-F-00-022 

Environmental Protection May 2000 

Agency 

Office of Transportation and Air Quality 

Regulatory 

Announcement 

Proposed Heavy-Duty Engine and 

Vehicle Standards and Highway 

Diesel Fuel Sulfur Control 

Requirements 

The U.S. Environmental Protection Agency (EPA) is proposing a major 

program to significantly reduce emissions from heavy-duty engines and 

vehicles. This comprehensive national control program regulates the 

heavy-duty vehicle and its fuel as a single system. We are proposing 

new emission standards that will begin to take effect in 2007 and 

corresponding diesel fuel requirements that take effect in 2006. If fully 

implemented as proposed, this program will reduce emissions of oxides 

of nitrogen (NOx) and nonmethane hydrocarbons (NMHC), key 

ingredients in ozone, by 2.8 million and 305,000 tons per year in 2030, 

respectively. Particulate emissions from these vehicles would be 

reduced by 110,000 tons per year in 2030. 

Overview 

These proposed standards are based on the use of high-efficiency catalytic aftertreatment devices or comparably effective advanced technologies. Because these devices are damaged by sulfur, we are also proposing new fuel quality requirements to remove most of the sulfur from 

highway diesel fuel by the middle of 2006. These changes form the 

second phase of a two-phase Agency initiative, beginning with the 

previously set 2004 heavy-duty engine standards, to reconcile the heavyduty highway engine with the environment. 

Printed on Recycled Paper 
Heavy-Duty 

Engines 

This second phase will achieve emission reductions of upwards of 90 

percent or more over levels achieved by the phase 1 reductions, and will 

provide a clean diesel fuel in time for implementation of the light-duty 

Tier 2 standards. As a result, diesel vehicles of all sizes will achieve 

gasoline-like exhaust emission levels, in addition to their inherent advantages over gasoline vehicles with respect to fuel economy, lower greenhouse gas emissions, and lower evaporative hydrocarbon emissions. 

Background 

Diesel engines overwhelmingly dominate the bus and large truck markets 

and have been capturing a growing share of the light heavy-duty vehicle 

market over the last decade. The impact of diesel engines on air quality 

may grow even larger if automobile manufacturers carry out stated plans 

to increase sales of diesel-powered light-duty trucks and cars over the 

next few years. In light of the air quality concerns, we published an 

Advance Notice of Proposed Rulemaking (ANPRM) in May 1999 to 

investigate the possibility of bringing about dramatic improvements in 

diesel emissions control through a combination of fuel and vehicle 

changes. The fuel changes would enable not just heavy-duty diesel 

emissions control, but would also help to enable light-duty diesels to 

meet our recently adopted Tier 2 standards. Based on the air quality 

concerns and the comments we received on the ANPRM, we are now 

proposing a comprehensive national control program that covers heavyduty vehicles operated on any fuel. 

Proposed Standards for Heavy-Duty Highway 

Engines and Vehicles 

We are proposing a particulate matter (PM) emissions standard for new 

heavy-duty engines of 0.01 grams per brake-horsepower-hour (g/bhp-hr), 

to take full effect in the 2007 heavy-duty engine (HDE) model year. We 

are also proposing standards for oxides of nitrogen (NOx) and 

nonmethane hydrocarbons (NMHC) of 0.20 g/bhp-hr and 0.14 g/bhp-hr, 

respectively. These NOx and NMHC standards would be phased in 

together between 2007 and 2010, for diesel engines. The phase-in would 

be on a percent-of-sales basis: 25 percent in 2007, 50 percent in 2008, 75 

percent in 2009, and 100 percent in 2010. Because of the more advanced 

state of gasoline engine emissions control technology, these engines 

would be fully subject to these standards in the 2007 model year, although we request comment on phasing in these standards as well. In 

addition, we are proposing formaldehyde emission standards and new 

requirements for crankcase emissions control on turbocharged diesel 

engines. 

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Proposed Standards for HDEs 

PM 0.01 g/bhp-hr 

NOx 0.20 g/bhp-hr 

NMHC 0.14 g/bhp-hr 

Heavy-Duty 

Vehicles 

Proposed standards for complete heavy-duty vehicles (HDVs) would be 

implemented on the same schedule as for engine standards. For certification of complete vehicles between 8500 and 10,000 pounds gross vehicle 

weight rating (GVWR), the proposed standards are 0.2 grams per mile 

(g/mi) for NOx, 0.02 g/mi for PM, and 0.195 g/mi for NMHC. For 

vehicles between 10,000 and 14,000 pounds, the proposed standards are 

0.4 g/mi for NOx, 0.02 g/mi for PM, and 0.230 g/mi for NMHC. These 

standards levels are roughly comparable to the proposed engine-based 

standards in these size ranges. Note that these standards would not apply 

to vehicles above 8500 pounds that we classify as medium-duty passenger vehicles as part of our Tier 2 program because of their primary use as 

passenger vehicles (the final standards for these vehicles are in 65 FR 

6698, February 10, 2000). 

Proposed Standards for HDVs 

GVWR PM NOx NMHC 

8,500-10,000 0.02 g/mi 0.2 g/mi 0.195 g/mi 

10,000-14,000 0.02 g/mi 0.4 g/mi 0.230 g/mi 

Evaporative



Emissions



We are proposing to revise the evaporative emissions standards for 

heavy-duty engines and vehicles, effective in the 2007 model year. The 

proposed standards for 8500 to 14,000 pound vehicles are 1.4 and 1.75 

grams per test for the 3-day diurnal and supplemental 2-day diurnal tests, 

respectively. Slightly higher standards levels of 1.9 and 2.3 grams per 

test would apply for vehicles over 14,000 pounds. These proposed 

standards represent more than a 50 percent reduction in the numerical 

standards as they exist today. 

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Proposed Evaporative Emission Standards 

GVWR 3-Day Diurnal Test Supplemental 2-Day Diurnal Test

 8,500-14,000 1.4 g/test 1.75 g/test

 >14,000 1.9 g/test 2.3 g/test 

Proposed Standards for Diesel Fuel 

We are proposing that diesel fuel sold to consumers for use in highway 

vehicles have a sulfur content no greater than 15 parts per million (ppm), 

beginning June 1, 2006. This proposed sulfur cap is based on our assessment of how sulfur-intolerant advanced aftertreatment technologies will 

be, and a corresponding assessment of the feasibility of low-sulfur fuel 

production and distribution. We are seeking comment on voluntary options for providing refiners with flexibility in complying with the low 

sulfur highway diesel fuel program. In addition, we request comment on 

some potential flexibility provisions to assist small refiners in complying 

with the program. 

Health and Environmental Benefits 

Without significant new controls on motor vehicle emissions, millions of 

Americans will continue to breathe unhealthy air. The standards proposed 

would result in substantial benefits to the public health and welfare 

through significant annual reductions in emissions of NOx, PM, NMHC, 

carbon monoxide, sulfur dioxide, and air toxics. If fully implemented as 

proposed, this program will reduce emissions of NOx and NMHC, key 

ingredients in ozone, by 2.8 million and 305,000 tons per year in 2030, 

respectively. Particulate emissions from these vehicles would be reduced 

by 110,000 tons per year in 2030. 

Ozone causes a range of health problems related to breathing, including 

chest pain, coughing, and shortness of breath. PM is deposited deep in the 

lungs and causes premature death, increased emergency room visits, and 

increased respiratory symptoms and disease. With both ozone and PM, 

children and the elderly are most at risk. In addition, ozone, NOx, and PM 

adversely affect the environment in various ways, including crop damage, 

acid rain, and visibility impairment. Numerous studies also link diesel 

exhaust to increased incidence of lung cancer. 

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Cost of the Proposed Program 

The significant environmental benefits of this program would come at an 

average cost increase of about $1000 to $1600 per new vehicle, depending on the vehicle size. We estimate that the overall cost associated with 

lowering the sulfur cap from the current level of 500 ppm to the 15 ppm 

level proposed today will be approximately 3-4 cents per gallon, comprised of an approximately 4 cents per gallon increased cost to produce 

and distribute the fuel, and a cost offset of about 1 cent per gallon or 

more from the vehicle maintenance savings that result from the use of the 

cleaner fuel. 

Public Participation Opportunities 

We welcome your comments on this proposal. For instructions on submitting written comments, please see the Federal Register notice. You 

may submit written comments to EPA up to 90 days after the proposed 

rule is signed by the EPA Administrator. It is available from the EPA Air 

Docket by calling 202-260-7548; please refer to Docket No. A-99-06. In 

addition, you can access the proposed rule and related documents electronically on the Office of Transportation and Air Quality Web site at: 

http://www.epa.gov/otaq/diesel.htm 

The address for submitting written comments is: 

Margaret Borushko (Docket No. A-99-06) 

U. S. Environmental Protection Agency
 


Office of Transportation and Air Quality
 


2000 Traverwood Drive
 


Ann Arbor, MI 48105
 


You may also submit comments by email to diesel@epa.gov. 

In addition, public hearings will be held in Los Angeles, Denver, New 

York City, Chicago, and Atlanta approximately three weeks after publication of the proposed rule in the Federal Register. Additional information 

about the hearings will be published in a supplemental notice in the 

Federal Register in the near future. 

For More Information 

You can access documents related to the proposed rule and the ANPRM 

electronically at the Internet site listed above, or by contacting Margaret 

Borushko at the address given above. 

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