The California Air Resources Board (CARB) staff are in the process of developing new regulations to further reduce emissions from transport refrigeration units (TRU) and TRU generator sets in California.
Owners of older cars and light trucks in California have long known that smog certification is required every other year as a condition of vehicle registration. No certification, no registration. It’s been that way since 1984. Big rigs, unlike passenger vehicles, don’t have to pass state smog checks. Diesel trucks spew the major portion of oxides of nitrogen and diesel particulate matter into California’s air.