Emissions control systems may soon be required by the EPA on large diesel
and petrol highway trucks and buses. The EPA is proposing regulation for onboard diagnostic (OBD) systems for these vehicles to ensure that emissions control systems work correctly as part of the Clean Diesel Truck and Bus Program. OBDs monitor emissions control components, detect faults and alert drivers to any problems and have been in use in passenger vehicles since the mid-1990s.
The real win here is that trucks and buses will finally be made to use technology which has been keeping emissions from passenger vehicles down for the last ten years. Significant falls in emissions are expected including significant reductions in NOx, particulate matter, non-methane hydrocarbons, carbon monoxide, sulfur dioxide, and air toxics.
[Source: Diesel Forum]