Is It Illegal to Warm Your Car Up in Idaho If You’re Not Inside Of It?

Cooler temperatures may have taken a little longer to arrive than they have in the past, but those frigid mornings when you want to order a peppermint mocha just to hold it are finally here! 

Simply opening the weather app on your phone and seeing any number below 32º is enough to make you want to roll over, snuggle back up under the covers and wait until later in the day to leave the house. Unfortunately, the kids have to be at school by the time the bell rings and we’re fairly sure “it was too cold” won’t fly as a valid excuse if you’re late for work. 

Depending on how far your destination is from your home, your vehicle might not even get toasty warm by the time you get there. To make driving on a frigid morning more bearable, you may be tempted to run outside and start your car so that it's warm by the time everyone is showered, dressed and fed. It seems harmless enough, right? 

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There are at least 29 states that disagree with you including Idaho’s neighbor, Washington. Many cities in Utah have similar anti-idling ordinances, including Salt Lake City.  

Is it Illegal to Warm Up Your Car in Idaho?

The short answer is “no.” The long answer is “no, but it was for 29 years." From 1988-2017, Idaho’s code regarding unattended running vehicles read: 

No person driving or in charge of a motor vehicle shall permit it to stand unattended without first stopping the engine, locking the ignition, removing the key from the ignition, effectively setting the parking brake and, when standing upon any grade, turning the front wheels to the curb or side of the highway.

In 2017, that part of Idaho code was amended to read:

No person driving or in charge of a motor vehicle shall permit it to stand unattended without first locking the vehicle if the engine is running, effectively setting the parking brake and, when standing upon any grade, turning the front wheels to the curb or side of the highway. The provisions of this section do not apply to motor vehicles on private property.

When the amendment was originally introduced in the House, lawmakers were clear in explaining that the change was to specifically allow drivers to warn up the interior of their vehicle in cold weather. It was signed into law on March 20, 2017. 

We think this was kind of them to do. We’re sure that locksmiths do too. It’s really easy to lock your keys in your car if you follow the law the way it’s written. 

Now keep in mind, that municipalities do have the option to make their own rules when it comes to idling vehicles. In Ketchum, it's illegal in most cases to leave your vehicle running and idle for more than three minutes. You may do so if it's essential to clear your windshield of frost, but not if it's simply warming up the car for the comfort of you and your passengers.

Is Warming Up My Car Bad for the Engine?

Last December, KTVB shared an article titled “Yes, warming up your car before driving in cold weather can damage the engine” as part of their “Verified” series. People lost their minds. That post led to more than 1,100 comments and 310 shares. 

Long story short? They found that warming your car up and letting it idle can strip away oil from pistons and cylinders, which could shorten the life of your engine. They say that 30 seconds is enough time to let your engine warm up before driving to your destination on a cold morning. 

People in the comments section aggressively disagreed. Whoever wrote the article talked to several environmental agencies and mechanics. We’re NOT mechanics, so we’ll let you make your own decision. If you want to chance it in Idaho? Go for it.