On-Road Heavy-Duty Diesel Engine In-Use Compliance Program

This page last reviewed July 18, 2007


While light-duty vehicles have been subject to in-use compliance testing since 1983, to date no such testing has been conducted on heavy-duty diesel engines in California. In-use compliance testing is a key strategy to air quality improvement because it ensures that vehicles/engines meet applicable emission standards throughout their useful life. Beginning in 2001, ARB staff started working collaboratively with the United States Environmental Protection Agency (U.S. EPA) and engine manufacturers to develop an in-use testing and compliance program based on performing the Not-to-Exceed (NTE) certification test. The NTE test, applicable beginning with 2005 model year engines, allows testing to be conducted with an on-board portable emission measurement system (PEMS) during on-road operation. Testing with PEMS will avoid the high costs and the lengthy testing time associated with traditional engine testing on a dynamometer in the laboratory.

In May 2003, the general structure of a heavy-duty diesel engine in-use testing and compliance program was developed and agreed-upon by all parties. Based upon this collaborative work, in June 2005, U.S. EPA adopted a manufacturer-run in-use testing program, in which all manufacturers of heavy-duty diesel engines sold elsewhere in the United States must comply with. On September 28, 2006, the Board adopted a heavy-duty diesel in-use compliance program that would make California requirements consistent with the federal requirements in this area. The enforceable program is expected to begin in December 2007 for gaseous emissions and in June 2009 for particulate matter emissions.


See the following for more information

Formal Regulatory Documents Use this link to view the formal regulatory documents. These documents include, but are not limited to, the Notice of Public Hearing, the Initial Statement of Reasons, the proposed regulations, and the Notice of Public Availability of Modified Text.
 Board Presentation Presentation from the September 28, 2006, Board Hearing when this regulation was adopted.
Outline of the general structure of the in-use compliance program "Outline of Regulatory Proposal (NPRM) for Manufacturer-Run In-Use Heavy-Duty Vehicle NTE Testing Program," May 2003, developed by U.S. EPA, ARB, and the Engine Manufacturers Association.
Memorandum of Agreement for measurement accuracy margins "Program to Develop Emission Measurement Accuracy Margins for Heavy-Duty In-Use Testing," May 2005.
Test plan to determine PEMS gaseous measurement allowance "Test Plan to Determine PEMS Measurement
Allowances for the Gaseous Emissions Regulated under the Manufacturer-Run Heavy-Duty Diesel Engine In-Use Testing Program," October 25, 2005.
U.S. EPA Manufacturer Guidance Letter for vehicle screening "Manufacturer-Run, Heavy-Duty In-Use Testing Program: Vehicle Screening Guidance," CISD-06-010(HD); May 5, 2006.
U.S. EPA Manufacturer Guidance Letter for reporting "Manufacturer-Run, Heavy-Duty In-Use Testing Program: Reporting Guidance," CISD-06-011(HD); May 5, 2006.


Related Links

U.S. EPA's Website on Heavy Trucks, Buses, and Engines Find out about the Final Rule for In-Use Testing for Heavy-Duty Engines and Vehicles, signed June 3, 2005, and other heavy-duty engine and vehicle rulemaking efforts.
In-Use Testing of Light-Duty
and Medium-Duty Vehicles
Find out about the existing in-use testing program on light-duty and medium-duty vehicles.


Where Can I Get More Information?
For more information, please contact Dipak Bishnu at (626) 575-6696.

On-Road Heavy-Duty Vehicle Program
Diesel Activities: Mobile Vehicles and Equipment
Diesel Activities - Certifications & Verifications

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