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Regulatory

Announcement

Office of Transportation

and Air quality

EPA420-F-04-042

June 2004

Proposed In-Use Testing Program for

Heavy-Duty Diesel Engines and Vehicles

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

manufacturer-run, in-use emissions testing program for heavy-duty

diesel trucks. This proposal is the first step in implementing a June

2003 settlement agreement between the Engine Manufacturers

Association (EMA) and EPA. Under this in-use testing program,

manufacturers will measure gaseous and particulate exhaust emissions

from diesel engines using portable onboard emission measurement

systems. This cooperative effort represents a significant advance in

helping to ensure that the benefits of more stringent emission standards

are realized under real-world driving conditions.

Background

EPA has issued five rules regarding diesel engines since 1999. These

include the 2004 and 2007 Heavy-Duty Diesel Motor Vehicle Engines

Rules, Recreational Marine Diesel Engines Rule, Commercial Marine

Diesel Engines Rule, and the Clean Air Nonroad Diesel Rule for compression-ignition engines. EMA and some manufacturers challenged

parts of the highway and marine rules regarding legal authority and

technical feasibility of certain emission standards called the Not-ToExceed Standards (NTE). EPA, the California Air Resources Board

(CARB), and EMA, along with its member companies, have worked

cooperatively to reach an agreement. The resulting settlement included

provisions for proposing a manufacturer run, in-use emissions testing

program.
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The new testing program will assess in-use gaseous and particulate

exhaust emissions from heavy-duty diesel trucks using portable emission

measurement systems for the first time. Previously, testing engine emissions involved removing the engine from the truck and testing the engine

in a laboratory on an engine dynamometer. Starting in the mid-1990s

EPA facilitated research into portable systems by developing and using

prototype systems in its compliance programs. Portable systems were

placed inside of vehicles to measure emissions performance during realworld operating conditions. It became clear that these systems offered

advantages over conventional approaches to assess in-use exhaust emissions from engines for design improvement, research, modeling, and

compliance purposes.

In a largely unprecedented example of proactive government and industry cooperation, prior to any formal rulemaking initiative, manufacturers

have agreed to implement this new type of in-use emission testing program. The resulting collaborative program, which advances EPA’s Clean

Diesel Program, is a significant step forward for both parties in helping

ensure that heavy-duty diesel engines comply with applicable emission

standards throughout their useful lives while reducing overall compliance

burdens.

Key Elements of the Proposed Program

We are proposing to establish a manufacturer-run, in-use NTE testing

program for vehicles with heavy-duty diesel engines, beginning with a

pilot program in calendar years 2005 and 2006. The pilot program will

allow EPA and the manufacturers to gain the necessary experience with

in-use testing protocols and generation of in-use test data using portable

emission measurement systems. Beginning in calendar year 2007, when

the NTE and tailpipe emission standards for nitrogen oxides (NOx) and

particulate matter (PM) take effect, the fully enforceable program will

apply to 2007 and later model year engines.

Under the program, testing will be conducted and paid for by manufacturers with EPA oversight on in-use vehicles, under real-world driving

conditions, within the engine’s useful life. Four pollutants will be measured: hydrocarbons (HC), carbon monoxide (CO), NOx, and PM.

Manufacturers will test fleet or customer-owned, in-use trucks, tapping

into existing customer relationships and creating new lines of communication with customers, all of which is expected to fortify the engine

development process. This will enhance the manufacturer’s ability to

catch any problem engines early on, and encourage future engine designs

that are cleaner and more durable.
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Manufacturers will monitor compliance by testing in-use diesel engines

during normal vehicle operation. If noncomplying engines are identified,

the manufacturer will test more engines for the purpose of determining if

any further action is necessary. EPA will likewise use the in-use data to

make independent evaluations about the possible need to pursue further

actions.

This program will address a serious, long-standing need for "real-world"

in-use testing data, which have never been collected on this large a

scale. We expect that the wealth of in-use test data generated will have a

number of valuable uses in addition to monitoring heavy-duty diesel

engines for NTE compliance purposes. We will use the data to assure

that emission standards are being met; we may also use the information

in the development of in-use emission factors for emissions and air

quality modeling. The data will also be available to the public for review

and analysis.

Other Programs

California's involvement in the development of this program was critical

in assuring that engine manufacturers are subject to a consistent national

in-use NTE test program. CARB intends to adopt a parallel in-use

testing program for 2007, soon after EPA completes its final rule for this

program.

In addition, EPA is developing an outline for a similar in-use testing

program for nonroad diesel engines covered by the emission standards

finalized in May 2004. Such a program will be patterned after the heavyduty truck in-use testing program, but will address some unique issues

pertaining to the nonroad market. We anticipate publishing a proposed

rule for public comment in 2005.

Economic, Health and Environmental Impacts

EPA expects that 14 heavy-duty diesel engine manufacturers will be

involved in the program. Total annual costs are estimated at about $1

million. This proposed in-use emissions testing program is expected to

help ensure that the intended health and environmental benefits from

recently-adopted emission regulations are realized throughout the entire

useful lives of heavy-duty diesel engines.
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Public Participation Opportunities

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

available from the EPA Air Docket by calling (202) 566-1742; please

refer to Docket No. OAR-2004-0072. In addition, you can access the

proposed rule and related documents on EPA's Office of Transportation

and Air Quality Web site at:

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

A public hearing will be held in Washington, DC, on July 15, 2004, at

10:00 am. Additional information about the hearing will be printed in the

Federal Register.

For More Information:

For more information, please contact Richard Wilcox at:

U.S. Environmental Protection Agency

Office of Transportation and Air Quality

Assessment and Standards Division

2000 Traverwood Drive

Ann Arbor, MI 48105

(734) 214-4390

E-mail: wilcox.rich@epa.gov