RALEIGH — reallycold weather hits the Triangle one local survival technique is the "warming up" of the family vehicle. You know the routine: run out in a bathrobe and boots, start the car, the defroster, and the heater, and run back in to change clothes.

In the long run, however, police say this could become an expensive habit since car thieves don't take the winter season off.

Rental agent pat Reeves says it's never a good idea to leave an unattended car running.

Choosing which car to hit can be easy for a thief. All he has to look for is the billow of steam coming out of the exhaust pipe into the frigid air. Mechanic Greg Williamson says it's a dead giveaway.

Whether that tempting, early-morning steam cloud is in front of a house or in a public parking lot, to a thief it's an invitation. Shonda Cox says shehasto leave her car running in cold weather, but she takes precautions.

Police say if you have any choice at all in the matter, turn the car off if you don't want to lose it.