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Regulatory

Announcement

 Printed on Recycled Paper

United States

Environmental Protection

Agency

Air and Radiation EPA420-F-00-026

July 2000

Office of Transportation and Air Quality

Final Emission Standards for 2004

and Later Model Year Highway

Heavy-Duty Vehicles and Engines

The U.S. Environmental Protection Agency (EPA) is issuing a final rule

for the first heavy-duty trucks and buses. In the first phase, EPA is

finalizing new diesel engine standards beginning in 2004 for all diesel

vehicles over 8,500 pounds. Additional diesel standards and test

procedures in this final rule will begin in 2007. Heavy-duty gasoline

engines will be required to meet new, more stringent standards starting

no later than the 2005 model year. The new standards require gasoline

trucks to be 78 percent cleaner and diesel trucks to be more than 40

percent cleaner than today’s models.

The second phase of the program will require cleaner diesel fuels and

even cleaner engines, and will reduce air pollution from trucks and

buses by another 90 percent. EPA expects to issue the final rule, to take

effect in 2006-2007, for the second phase of the program by the end of

this year.

Highlights of the Final Rule

• EPA is reaffirming a combined standard for smog-causing oxides of

nitrogen (NOx) and hydrocarbons (HC) of 2.4 grams per brake horsepower-hour (g/bhp-hr). The current standard for NOx is 4 g/bhp-hr

and the HC standard is 1.3 g/bhp-hr. This standard represents a more

than 40 percent reduction in emissions of NOx, as well as reductions

in HC, from diesel trucks and buses.

HeavyDuty Diesel

Engines
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• The rule adds new test procedures and compliance requirements to

ensure that emission standards are met in actual use across a wide

range of operating conditions. These requirements begin in the 2007

model year.

• The rule requires on-board diagnostic (OBD) systems for engines

between 8,500 and 14,000 pounds to be phased-in, beginning in 2005.

These systems will identify the failure of emissions control system

components.

• Vehicles less than 14,000 pounds gross vehicle weight rating are

subject to emission standards and testing similar to the current program for light-duty vehicles and light-duty trucks.

• The rule adds new, more stringent emission standards for vehicles

with a gross vehicle weight rating below 14,000 pounds (see table

below). The current NOx and HC standards are 4.0 and 1.1 g/bhp-hr,

respectively.

Gross Vehicle

Weight Rating

HC NOx

8,500 - 10,000 lbs 0 e .28 g/mile 0.9 g/mil

10,001 - 14,000 lbs 0 e .33 g/mile 1.0 g/mil

• New gasoline heavy-duty engines used in a vehicle with a gross

vehicle weight rating above 14,000 pounds must meet a combined HC

and NOx standard of 1.0 g/bhp-hr. The current NOx and HC standards

are 4.0 and 1.9 g/bhp-hr, respectively.

• OBD systems for engines between 8,500 and 14,000 pounds gross

vehicle weight will be phased-in.

• The rule incorporates flexibility and incentive mechanisms that will

encourage manufactures of gasoline trucks to meet these standards as

early as 2003 or 2004. Due to the requirements of the Clean Air Act,

the earliest implementation of new emission standards is the 2005

model year.

HeavyDuty

Gasoline

Engines &

Vehicles
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Health and Environmental Benefits

This rule will reduce emissions of smog-causing NOx by 2.4 million

tons each year when the program is fully implemented in 2030. Ozone

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

pain, coughing, and shortness of breath. Particulate matter (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.

In addition, there is great concern about the adverse health effects associated with exposure to diesel exhaust. Exposure is widespread, particularly in urban areas, and according to several national and international

agencies, there is increasing evidence that diesel exhaust or diesel particulate matter (soot) may cause lung cancer in humans. Non-cancerous

effects such as lung damage and respiratory problems are also associated

with exposure to diesel exhaust.

Costs of the Program

The significant benefits of this program will come at an average projected long-term cost increase of less than $400 per vehicle for heavyduty diesel engines and less than $300 per vehicle for heavy-duty gasoline vehicles and engines.

Background

In 1997, EPA issued a new NMHC+NOx standard for heavy-duty diesel

engines, starting with the 2004 model year, and committed to review the

appropriateness of this standard in 1999. This final rule reaffirms those

standards for diesel engines and finalizes new standards for heavy-duty

gasoline engines.

In 1998, the Agency signed consent decrees with several of the largest

heavy-duty diesel engine manufacturers to address several in-use emission problems. The final rule contains several new provisions for the

heavy-duty diesel engine manufacturers not contained in the 1997 final

rulemaking that arose because of the issues highlighted by these consent

decrees. These provisions include new emission tests and compliance

requirements that are designed to ensure that heavy-duty diesel engines
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meet emission standards in actual use and over a broad range of operating conditions. In the consent decrees, the manufacturers agreed to

introduce cleaner new engines and rebuild older engines to cleaner

levels. Under the agreements, the companies will meet emission levels

for heavy-duty diesel engines beyond what the law requires by October

2002.

On May 17, 2000, EPA proposed more stringent emission standards for

heavy-duty vehicles that would reduce smog-causing emissions from

trucks and buses by 95 percent beyond current levels. Soot emissions

also would be reduced by 90 percent beyond current levels. In order to

meet these more stringent standards for diesel engines, the proposal

requires the sulfur content of diesel fuel to be capped at 15 parts per

million – a 97 percent reduction. EPA plans to finalize these standards by

the end of the year, and the standards will take effect in 2006 - 2007.

For More Information

You can access this final rule and related documents electronically on the

Office of Transportation and Air Quality (OTAQ) Web site at:

http://www.epa.gov/otaq/hd-hwy.htm

You can also contact the OTAQ library for document information at:

U.S. Environmental Protection Agency

Office of Transportation and Air Quality

NVFEL Library

2000 Traverwood Drive

Ann Arbor, MI 48105

(734) 214-4311