United States          Office of Transportation                                 EPA420-F-05-021
Environmental Protection   and Ajr Qua|jty                                        June

                   TTie C/.^. Environmental Protection Agency (EPA) is establishing a
                   manufacturer-run, in-use emissions testing program for heavy-duty
                   diesel trucks. Under this program, manufacturers will measure gaseous
                   and particulate exhaust emissions from diesel engines using portable
                   onboard emission measurement systems. This cooperative effort repre-
                   sents a significant advance in helping to ensure that the benefits of more
                   stringent emission standards are realized under real-world driving
                   EPAhas issued five rules regarding diesel engines since 1999. These include
                   the 2004 and 2007 Heavy-Duty Diesel Motor Vehicle Engines Rules, Recre-
                   ational Marine Diesel Engines Rule, Commercial Marine Diesel Engines Rule,
                   and the Clean Air Nonroad Diesel Rule for compression-ignition engines. The
                   Engine Manufacturers Association (EMA) and some manufacturers chal-
                   lenged parts of the highway and marine rules regarding legal authority and
                   technical feasibility of certain emission standards called the Not-To-Exceed
                   Standards (NTE). EPA, the California Air Resources Board (ARE), and
                   EMA, along with its member companies, worked cooperatively to reach a
                   settlement agreement that included provisions for a manufacturer run, in-use
                   emissions testing program. This final rule implements the key elements of that

The new testing program will assess in-use gaseous emissions (hydrocarbons,
carbon monoxide, and nitrogen oxides) and particulate matter from the
exhaust of heavy-duty diesel trucks. For the first time, this will be accom-
plished using portable emission measurement systems. Previously, engine
emissions testing 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 the vehicles to measure emissions performance during real-world
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.
Program  Overview
Under the program, manufacturers will test fleet or customer-owned, in-use
trucks. Manufacturers will tap into existing customer relationships and create
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.

Manufacturers will monitor compliance by testing in-use diesel engines during
normal vehicle operation. If noncomplying engines are identified, the manu-
facturer 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 indepen-
dent evaluations about the possible need to pursue further actions. The in-use
test data, which have never been collected on this large a scale, will be used
by EPA to assure that emission standards are being met, and by manufactur-
ers to improve their engine designs. The data will also be available to the

Key Elements
  *  Fully enforceable program beginning in the 2007 model year for gaseous
     emissions, when new NTE and tailpipe emission standards for nitrogen
     oxides (NOx) and particulate matter (PM) take effect.
  *  Pilot program for gaseous emissions for 2005 and 2006 model years
     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.
    Enforceable and pilot programs for PM begin one year after the gaseous
     programs begin.
    Monitors in-use emissions of diesel vehicles with portable emission
     measurement systems. Pollutants to be measured: Hydrocarbons (HC),
     Carbon Monoxide (CO), NOx and PM.
  *  Testing will be conducted on in-use vehicles, under real-world driving
     conditions, within the engine's useful life to monitor for NTE compliance
     and to help ensure overall compliance with the emission standards.
    Measurement "accuracy"margins established to accountforthe emissions
     measurement variability associated wiht these usnits in the field.
       o During the pilot program years, manufacturers will use interim
         margins based on current experience with portable and laboratory
         measurement systems.
       o Accuracy margins for the fully enforceable program are being
         developed through ajointEPA-industry research program.
    Testing conducted and paid for by manufacturers with EPA oversight.
  *  Addresses a serious, long-standing need for "real-world" in-use testing
  *  The California Air Resources Board intends to adopt a parallel in-use
     testing program.
    A nonroad diesel engine in-use testing program patterned after the
     heavy-duty truck program is expected in the 2010 time frame.
Economic,  Health       Environmental  Impacts
EPA expects that 13 heavy-duty diesel engine manufacturers will be involved
in the program. Total annual costs are estimated at about $1.7 million.

This 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

For More  information
You can access documents on this final rule on EPA's Office of Transportation
and Air Quality Web site at:

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

For further information, please contact Rich Wilcox at:

       U.S. Environmental Protection Agency
       Office of Transportation and Air Quality
       2000 Traverwood Drive
       Ann Arbor, MI 48105
       E-mail: wilcox.rich@epa. gov