Should you warm your car up before driving in extreme cold? And is it legal?

When meteorologists begin using terms like “polar vortex” to describe the weather, you might employ the life hack of warming up your car for a few minutes before leaving the house.

But should you warm your car in cold weather? And is it even legal?


For years, Maryland’s Vehicle Law forbade drivers from leaving their cars running unattended. The law was, at times, erratically enforced in the greater Baltimore area.

Legislators updated the law in 2015 to include exceptions for vehicles on private property, not open to the public, and vehicles with an engine that can be started using a remote keyless ignition system. In those circumstances, drivers can leave their cars unattended for up to five minutes when the car is not in motion.


On days when the temperature dips below freezing, it is a good idea warm your car up if only to get the fluids moving through the engine, said mechanic Scott Colom with A1 Auto Three Brothers Car Repair in Baltimore.

In the 1960s and ’70s, cars were designed in such a way that they required warming up on particularly cold days, or else they would not run, Colom said.

These days, cars and trucks typically only need a minute or so to warm to avoid wear on the engine, he said.

“Most of the time, I let it warm up before jumping up and going,” Colom said of his own truck. “I want the transmission fluid to pump through a little and get circulating.”

The only mechanical downside of leaving a car idling for a minute is the gas wasted, he said.

Still, the act of leaving a car on and unattended creates an opportunity for criminals to steal the vehicle, said Nicole Monroe, a spokeswoman for the Baltimore Police Department.

Baltimore has seen a few cases in recent years in which people’s cars were stolen while they were left on and unattended, Monroe said.

“When you have temps that are dipping in the minus category and have to go to work or have little ones, it's enticing to turn the car on,” she said. “You may do it five or six times and get away with it, but you are creating an opportunity for a criminal. Your car may be stolen.”

Here's a few tips Baltimore residents can take to stay safe during the region's cold snap.

These days, some technology allows cars to turn on and heat up remotely. Those devices typically turn the car off the minute someone without the key opens the door, Monroe said.

The law does allows for those keyless ignition systems to be used.

However, if a car is stolen because it was left on and unattended, the department will issue citations, Monroe said.

Violating this law in Maryland carries a fine of $70 and one point against one’s driving record. Additionally, unattended vehicles that slip out of gear and cause an accident could result in a ticket with a $110 fine and three points against one’s driving record, according to the Baltimore County Police Department.


What is the polar vortex? It's not a new weather phenomenon — it's an area of frigid air and low atmospheric pressure over each of Earth's poles. But it is making an unusual intrusion into the eastern United States, actually the result of warming at the North Pole.

Monroe was unsure how many such citations have been issued in Baltimore, she said.

In 2018, more than 1,800 vehicle thefts were investigated in Baltimore County, the majority of which involved someone warming up a car or leaving keys inside the vehicle, said police spokeswoman Jennifer Peach in an email Wednesday.

Stolen vehicles are commonly used to commit other crimes and aid criminals in evading detection, she said.

“The victim not only suffers the loss of their vehicle in these circumstances, but are held responsible by their insurance company and may additionally suffer increased insurance rates, loss of insurance, or covering the cost of a new vehicle,” she said. “In addition, the investigation of these crimes that could be avoided takes police officers off the road where they could be working to prevent crimes or responding to emergency calls.”

The law should not be viewed as a reduction in a citizen’s freedoms, Peach said.

“It’s common sense,” she said.

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