It’s cold in New Jersey and that means motorists are warming up their cars.

Just don’t do it for too long.

New Jersey prohibits idling — defined as when the engine is running but the vehicle is not moving — to no more than 3 minutes under most circumstances.

Drivers of passenger and commercial vehicles may face a $250 fine for a first offense, according to the state Department of Environmental Protection.

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Fines may rise to $500 for a second offense, and to $1,000 for third and subsequent violations, DEP said.

The anti-idling law, which applies year-round, is aimed at safeguarding health and the environment.

While idling in some cases is unavoidable — the law does not, for example, apply to drivers stalled in traffic — it is also the source of potentially deadly air contaminants.

New Jersey Sierra Club Director Jeff Tittel said the law merits additional education and enforcement.

“It’s violated all the time, even in the summer. As you’re idling, you’re polluting the neighborhood for no reason," Tittel said.

In addition to exempting fire, police, snow removal, and utility vehicles, the anti-idling law offers additional leeway when temperatures slip several degrees below freezing.

Drivers may idle for up to 15 minutes, if the vehicle has been stopped for three hours, if the temperature is below 25 degrees.

Tickets are issued infrequently.

Of the 262 summonses processed in New Jersey municipal courts last year, less than half, 103, resulted in a finding of guilty, according to state records.

There were 5 not-guilty findings and 154 dismissals.

READ MORE: Warming up your car too long is illegal — and just another one of N.J.’s dumb laws

Rob Jennings may be reached at rjennings@njadvancemedia.com. Follow him on Twitter@RobJenningsNJ. Find NJ.com on Facebook.

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