TULSA, Oklahoma - Thieves are stealing cars at an alarming rate in Tulsa; and, in some cases, the owners are practically handing over the keys.

Police say, in just the past few days, 15 cars have been stolen in Tulsa because the owners leave them running to warm up.

While many people turn their cars on automatically these days, if you don't have auto-start not only could you be a victim, you could be breaking the law.

In the winter, no one likes getting into a car that could double as a deep freezer, so sometimes drivers leave their cars running and unlocked to avoid that - but police say it might be better to brave the cold.

They say not only could you be targeted by thieves, it’s also illegal.

"It is illegal, and you're really rolling the dice on whether you become a victim or not," Sergeant Shane Tuell said. “It'll get you a $30 citation."

That doesn't include your driveway, but police said that's also not recommended. They say thieves see an unlocked, running car as “opportunity.”

"That's usually what they do,” Tuell said. “They look for the telltale signs that the car is running and left unattended."

In the month of December alone, the sergeant said 18 vehicles were reported stolen - and while not all of them were cars left running, he said it's a chance you don't want to take.

In February 2015, a man left his truck running at a QuikTrip only to come back outside and find it gone.

Police said the man who stole it, Clark Gatwood, had done it several times before. He was eventually arrested and convicted of auto theft.

Police say all drivers should be on the lookout. Not only have 15 cars been stolen from people leaving them running, but thieves have stolen 60 cars in just the last three days, which is more than double the amount for all of December.