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Idle-free Boston

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

Unnecessary engine idling can be a significant source of air pollution, particularly for people near the source. MGL Chapter 90, Section 16A states that:

No person shall cause, suffer, allow or permit the unnecessary operation of the engine of a motor vehicle while said vehicle is stopped for a foreseeable period of time in excess of five minutes.

In Boston, the Air Pollution Control Commission enforces this law. Violators are liable for $100 tickets per offense.

Facts about idling your car

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How can I be idle-free?

Turn off the engine as soon as you pull over or as soon as it's no longer needed to conduct work.

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.
  • 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.

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.


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.

About our work

The Air Pollution Control Commission engages in many efforts to educate drivers and institutions about the costs of excessive idling and the benefits of idling reduction. The City of Boston is itself engaged in an intensive effort to reduce idling in the City fleet.

Our work includes:
  • conducting direct outreach and education to idling drivers
  • partnering with neighborhood and nonprofit groups, and
  • responding to citizen complaints about problem areas. (For more information, see EPA: Idling.)
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