6o
           Amendments to the  Manufacturer-Run,
           Heavy-Duty  Diesel In-Use Engine and
           Vehicle Testing 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 mar-
           gin 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
       United States
       Environmental Protection                                     EPA420-F-08-01 1
       A9encv                                                  February 2008

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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

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           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 48 1 05

                    Voice-mail: (734)  214-4636

                    E-mail: asdinfo@epa.gov
          Heavy-Duty Diesel In-Use Engine and Vehicle Testing Program

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