When it’s bitterly cold outside, most people opt to stay inside. But if they must leave the house, some will warm up their car for a few minutes before driving away.

This is a great idea for comfort’s sake, but beware: Not only is a driverless idling car a thief’s dream come true, it might also land the owner a ticket.

A Minneapolis city ordinance makes it illegal for an owner to leave a vehicle running unattended. The fine for violating the ordinance is $34.

Carol Oosterhuis, a crime prevention specialist with the Minneapolis police, said the ordinance and accompanying fine are designed to tell people to take serious measures to protect their property.

According to Minneapolis police statistics, auto theft numbers jump up in the colder winter months.

During January, February, March, October, November and December of 2006, nearly 2,000 cars were stolen in Minneapolis, according to police statistics. That’s about 55 percent of all cars stolen for the year.

According to the same statistics, in 2005, 2,200 car thefts occurred during the same timeframe – nearly 56 percent.

For Precinct 2, where the University is located, the numbers are less dramatic.

Of the 1,100 cars stolen in the past two years, 570 were stolen during the winter months.

Auto thefts in the Marcy-Holmes and Southeast Como neighborhoods remained steady between cold and warm months, Oosterhuis said.

But, she said, many variables must be factored in when talking about the neighborhoods around campus.

During the summer months, there are fewer cars and people, which can lead to fewer auto thefts occurring, Oosterhuis said.

Whether the number of vehicles stolen increases in the cold months or not, some of them are the result of people leaving their keys in idling cars.

Steve Johnson, University police deputy chief, said these thefts happen every year when it gets cold and people need to warm up their cars.

“People looking to rip off cars, that’s what they’re looking for,” he said. “They’re able to get into those cars in seconds.”

Johnson said the only reason someone should leave a car running is if it is done with a remote car starter.

Some of these devices will start a car from a distance while preventing the vehicle from being driven without the key in the ignition.

If police pull over a stolen car and the thief has the keys, authorities will be unable to prosecute the person, Johnson said.

Oosterhuis said it comes down to a case of he-said, she-said.

“Chances are, they’ll say, ‘They gave me the keys,’ ” she said. “But if the (steering) column is peeled, it’s more evidence it’s a stolen vehicle.”

Melissa Smith, who works in patient accounting at Boynton Health Service, said she typically lets her car warm up before traveling. If she’s at her St. Paul home, Smith said she will start her car and go back inside.

“I have two sets of keys,” she said. “I leave one locked inside and keep the other with me.”

Even with this precaution, a thief could smash a window and quickly steal the vehicle.

“It’s not a good idea to do it,” Smith said.

To avoid being a victim of auto theft, Oosterhuis advised people to park in well-lit areas, always lock car doors, never leave anything valuable inside a vehicle, or get a steering wheel locking device like The Club.

Lastly, Oosterhuis said, awareness is another key to preventing auto theft.

“If you see somebody walking down the street and checking out cars, that’s suspicious,” she said. “Call 911.”