Clean Idle Vehicles
Need to idle the diesel engine in a late-model medium-duty truck longer than five minutes in California? Then you’ll need to find a rig with this sticker.
Truck drivers idle their engines for lots of reasons, but often it’s to stay comfortable when they’re parked at a job site for extended periods. But while an idling engine can keep a truck’s occupants warm or cool, idling engines running at low rpm aren’t very efficient when it comes to clean emissions.
In 2008, the California Air Resources Board made it illegal to idle new diesel-powered trucks with gross vehicle weight ratings over 14,000 pounds for more than five minutes. That GVWR is above heavy-duty pickups (which top out around 13,500 pounds) but covers most commercial chassis cab models.
The regulation requires manufacturers of California-certified 2008 and newer model-year diesel engines to incorporate a system that automatically shuts down the engine after five minutes of continuous idling or to certify the engine to a nitrogen oxide idling emission standard of 30 grams per hour. If the diesel engine meets this low NOx limit, it can idle indefinitely.