The Environmental Protection Agency (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 said December 13 that 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. The proposal also makes changes to certain existing OBD requirements for smaller highway diesel trucks.
Onboard diagnostic systems, used in passenger vehicles since the mid-1990s, monitor emissions control components, detect a need for emission-related repairs, and alert the vehicle's operator of these problems. They also help inform service technicians of problems. The OBD systems for highway trucks will work the same way, EPA said.
The proposed requirements are part of the Clean Diesel Truck and Bus Program, which will result in significant reductions of nitrogen oxides, particulate matter, non-methane hydrocarbons, carbon monoxide, sulfur dioxide, and air toxins from diesel-powered vehicles.