Department of Environmental Conservation

Pollution Testing on Exhaust Emissions from Heavy-Duty Vehicles

In the Stateís Heavy-Duty Vehicle Emissions Testing Program, diesel-powered trucks and buses are tested to determine whether their exhaust emissions meet prescribed air quality standards. Mandatory annual tests are performed on vehicles registered in the New York City metropolitan area, and random roadside tests may be performed on such vehicles anywhere in the State. The program is administered by three State agencies. The Department of Transportation (DOT) performs emissions tests on buses, the Department of Motor Vehicles (DMV) licenses the private inspection facilities performing annual emissions tests on trucks, and the Department of Environmental Conservation (DEC) performs roadside emissions tests on trucks. DEC also certifies the programís emissions testing equipment and inspects the licensed truck inspection facilities. Our audit focused on the responsibilities of DEC, and did not address the responsibilities of DMV and DOT.

We found that DECís roadside tests were performed in accordance with the required procedures and all 18 truck inspection facilities we visited were equipped with emissions testing equipment that had been certified by DEC. However, we found indications technological advancements in diesel engines may have made the Stateís testing process questionable on engines manufactured after 1996. If this is the case, the process could be significantly compromised, as vehicles that emit exhaust with unacceptably high levels of pollutants during normal highway driving may not be detected by the tests. We recommended DEC determine whether the current testing process was, in fact, appropriate for newer diesel engines.

DEC conducts inspections of the licensed truck inspection facilities to determine whether their emissions testing equipment is functioning properly and their emissions tests are properly documented. We found that DEC was conducting such inspections. However, we questioned whether the inspection coverage was adequate, as only 304 of the 619 licensed facilities (49 percent) were inspected in the two years covered by our audit, and facilities that failed their inspections were not always re-inspected to ensure that they had corrected their problems. We recommended that DEC establish appropriate inspection time frames for these facilities and perform inspections in accordance with these time frames.

For a complete copy of Report 2008-S-65 click here.