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EPA Wants Onboard Emissions Diagnostic Systems On Large Trucks, Buses

Part of Clean Diesel Truck and Bus Program.

The Environmental Protection Agency is proposing for the first time to require the emissions control systems of large diesel and gasoline highway trucks and buses to be monitored similarly to passenger cars.

The EPA said its proposed regulation for onboard diagnostic (OBD) systems for large trucks and buses would help ensure that emissions control systems work properly for the useful life of heavy-duty, on-road vehicles.

Onboard diagnostic systems, used in passenger vehicles since the mid-1990s, monitor emissions control components, detect need for emission-related repairs, and alert the vehicle's operator of these problems.

The proposed requirements are part of the Clean Diesel Truck and Bus Program, which the agency says will result in significant reductions of nitrogen oxides, particulate matter, non-methane hydrocarbons, carbon monoxide, sulfur dioxide, and air toxics from diesel-powered vehicles.

The proposal also makes changes to certain existing OBD requirements for smaller highway diesel trucks.

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