California Clean Idle Sticker Certifies You Can Do Exactly That

Clean idle sticker

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 rprm 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.

Certain vehicles, like buses and ambulances, are exempt from clean-air regulation.

For 2011, the Ram 4500/5500 and Ford F-450/F-550 chassis cab trucks meet CARB’s strict requirements. They use urea selective catalytic reduction to help accomplish this feat. To show off this capability, they get the fancy tamper-proof holographic sticker you see here.’s Editorial department is your source for automotive news and reviews. In line with’s long-standing ethics policy, editors and reviewers don’t accept gifts or free trips from automakers. The Editorial department is independent of’s advertising, sales and sponsored content departments.

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