A new regulation has gone into effect in California which limits idling of diesel- powered commercial vehicles, which weigh more than 10,000 pounds, to five consecutive minutes.

According to a California Air Resource Board (ARB) press release, , "the new rule will be enforced primarily by ARB diesel truck inspectors ... however, local law enforcement agencies and the California Highway Patrol can also issue citations."

California is the latest state to have new regulations on the books with the promise of active enforcement. Penalties in California start at $US100 for a first offence.

The California rule does have an exception for idling during resting or sleeping in a sleeper berth more than 100 feet from homes and schools; however, this would seem to apply when the sleeper cab is used for other activities while the truck is stopped (i.e.: using the computer or cooking food).