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The facts about idling your car

Last updated: 7/12/16

The facts about idling your car

Idling your car is bad for the environment. Here’s why you shouldn’t do it.

Leaving your engine running while your car is stopped is a bad idea for several reasons:

  • It's against the law. Unnecessary idling is punishable by a citation and fines. Repeat violations can lead to up to $25,000 in fines.
  • It pollutes the air. This is especially harmful to people with respiratory and heart diseases.
  • Idling cars add to smog and global warming.
  • It wastes fuel and costs money. The bigger the engine, the more money you waste.
  • It's bad for your car, too. It can cause damage to engine parts like cylinders, spark plugs, and the exhaust system.

Turn off your car when you park. If it's very hot or cold and you need to wait, park your car and go inside. The only time it’s okay to idle is when you need to power up for a specific purpose, like operating a lift. Even then, you should shut the vehicle off as soon as you don't need it anymore.


Contrary to popular belief, it doesn't take more fuel to re-start the engine than it does to idle. Idling for longer than 10 seconds uses more fuel than restarting.

You also don't need to idle your car to warm it up. Most vehicles need just a few seconds before they're ready to go. Driving your car will make it heat up faster than idling it.

Idling won't get you out of a parking ticket. In fact, idling in a no-parking zone is as much of a violation as parking in one.

Still have questions? Contact:
1 City Hall Square
Room 709
Boston, MA 02201-2031
United States