The EPA is proposing to require the emissions control systems of large diesel and gasoline highway trucks and buses to be monitored similarly to passenger cars. EPA says that the proposed regulation for onboard diagnostic systems 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. They also help inform service technicians what problem exists so that it can be repaired properly.

The OBD systems for highway trucks will work the same way.

The proposed requirements are part of the Clean Diesel Truck and Bus Program. The proposal also makes changes to certain existing OBD requirements for smaller highway diesel trucks.

EPA has established a public docket (Docket No. EPA-HQ-OAR-2005-0047) to submit or view public comments and to access documents related to the development of the proposed rule. Comments on this rule are due to EPA 60 days after publication of the Notice of Proposed Rulemaking in the Federal Register. Visit the docket at www.regulations.gov. 

More information on this action: http://www.epa.gov/obd/regtech/heavy.htm.