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In it for the Long Haul: Helping Large Trucks and Buses Maintain Clean Air Benefits

Release Date: 12/04/2008
Contact Information: Cathy Milbourn, (202) 564-4355 /

(Washington, D.C. – Dec. 4, 2008) New requirements will help ensure that heavy-duty vehicles run as cleanly as possible over their entire life on the road, and contribute to healthier and cleaner air for all Americans. On-board diagnostic systems (OBD) have been required on passenger cars since the mid-1990s, and will now be required on heavy-duty vehicles. OBDs monitor emission control systems and detect malfunctions. The system alerts the driver of the problem, enabling a service technician to diagnose and properly repair the problem.

The final rule is a major step in EPA’s efforts to work with the California Air Resources Board to develop a consistent national heavy-duty OBD program. OBD systems are an important tool for potentially improving air quality by helping states to meet National Ambient Air Quality Standards.

More information about on-board diagnostics: