Regulatory Announcement

Amendments to the Manufacturer-Run, 

Heavy-Duty Diesel In-Use Engine and 

VehicleTesting Program 

The U.S. Environmental Protection Agency (EPA) is publishing a Direct Final Rule to adopt final accuracy measurement margins 

for testing gaseous pollutants with portable emission measurement 

systems. Also, the rule makes several changes to the program in the 

early years of in-use testing. First, for particulate emissions (PM), this 

rule eliminates the first calendar year, i.e., 2006, of the two-year pilot 

program. Second, due to a delay in developing the final accuracy margin for PM, we are delaying the first year of the fully enforceable PM 

test program from the 2008 calendar year to the 2009 calendar year. 

During the 2008 calendar year, we are adding another year of pilot 

program for that pollutant. Third, and finally, we are extending the 

normal period for reporting in-test results during the initial years of 

the program and allowing certain short-term changes in how vehicles 

are recruited and tested. 

Overview 

In a rule published on June 14, 2005, EPA established a manufacturer-run, in-use 

testing program for heavy-duty diesel vehicles. The program assesses compliance 

with EPA’s Not-to-Exceed emission standards for these vehicles when operated on 

the highway. The in-use test data will also be used by EPA to assure that all other 

applicable emission standards are being met, and by manufacturers to improve their 

engine designs. 

At the time the original rule was promulgated, EPA established interim emission 

measurement “accuracy” margins for the requisite portable emission measurement 

devices pending the development of final accuracy margins through a comprehensive 

Office of Transportation and Air Quality 

EPA420-F-08-011 

February 2008 
Regulatory Announcement

research program with the California Air Resources Board and the Engine Manufacturers 

Association. In this rulemaking, we are adopting the final accuracy margins for gaseous 

pollutants from that work. 

Several changes are also being made the program during the early years of in-use testing. 

First, we are eliminating the first calendar year, i.e., 2006, of the two-year pilot program for 

particulate emissions (PM) in response to engine manufacturers’ concerns, which primarily 

relate to the availability and efficacy of the requisite portable measurement systems (PEMS) for 

that pollutant. Second, due to a delay in developing the final accuracy margin for PM under 

the aforementioned comprehensive research program, we are delaying the first year of the fully 

enforceable PM test program from the 2008 calendar year to the 2009 calendar year. During the 

2008 calendar year, there will be another year of pilot program testing for that pollutant. Third, 

and finally, we are extending the normal period for reporting in-use test results during the initial 

years of the program and allowing certain short-term changes in how vehicles are recruited and 

tested. These revisions are primarily intended to address delays in initiating the gaseous emission 

and PM pilot programs, manufacuturers’ concerns regarding the schedule for initial purchases 

of PM measurement systems, and manufacturers’ concerns regarding potential difficulties of 

initially instrumenting vehicles with these units. 

This rule is being released as a direct final rule. However, comments can be submitted under 

a parallel Notice of Proposed Rulemaking (NPRM). Comments will be accepted for 30 days 

beginning when the NPRM is published in the Federal Register. All comments should be 

identified by Docket ID No. EPA-HQ-OAR-2004-0072 and submitted by one of the following 

methods: 

Internet: www.regulations.gov 

E-mail: a-and-r-Docket@epa.gov 

Mail:


Environmental Protection Agency


Mail Code 2822T


1200 Pennsylvania Avenue NW


Washington, DC 20460


Hand Delivery: 

U.S. Environmental Protection Agency


EPA Headquarters Library


EPA West Building


Room 3334


1301 Constitution Avenue NW


Washington, DC


Heavy-Duty Diesel In-Use Engine and Vehicle Testing Program 
For More Information 

You can access the rule and related documents on EPA’s Office of Transportation and Air 

Quality (OTAQ) Web site at: 

www.epa.gov/otaq/marine.htm 

For more information on this Direct Final Rule, please contact the Assessment and Standards 

Division at: 

U.S. Environmental Protection Agency


Assessment and Standards Division


Office of Transportation and Air Quality


2000 Traverwood Drive


Ann Arbor, MI 48105


Voice-mail: (734) 214-4636 

E-mail: asdinfo@epa.gov

Regulatory Announcement

Heavy-Duty Diesel In-Use Engine and Vehicle Testing Program