Is it Illegal to Warm Up Your Car in Your Own Driveway in Arizona?

• Is it legal to leave your vehicle idling in your own driveway?
• Is there a time limit on idling?
• Why are we even asking these questions?

Can You Warm Up Your Car When It Gets Cold in Arizona?

As the colder weather settles into Arizona, it's time to start changing some of our habits. Even though we don't deal with severe cold in most of our state, it still takes our vehicles a little longer to get going when the thermometer falls.

Running out to warm up my vehicle has always been part of my winter routine, but now I might have to rethink this. While I finish getting ready to leave in the morning, my car idles in my driveway. But could I be breaking the law?

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Can You Legally Leave Your Vehicle Idling in Your Driveway?

Arizona Revised Statutes Title 28 - Transportation defines idling as:

[T]he operation of an engine in the operating mode where the engine is not engaged in gear, where the engine operates at a speed at the revolutions per minute specified by the engine or vehicle manufacturer for when the accelerator is fully released and there is no load on the engine. 

While there are some exemptions for vehicles that are allowed to idle, for the most part, it is illegal to allow your vehicle to idle, even if it's in your own driveway, for longer than five minutes. 

But It's My Driveway - Why Can't I Idle My Vehicle?

It all comes down to emissions. EPA Regulations have been placed on engine idling in Arizona to reduce air pollution, fuel consumption, and noise pollution.

According to the Arizona Department of Environmental Quality, an idling vehicle emits twenty times more pollution than a vehicle that's traveling at 30 miles per hour.

Idling wastes fuel and money, as well as causing wear and tear on your engine, which also adds up over time.

Not only is it inadvisable to warm up your car for longer than five minutes, but it's illegal in Arizona to warm up your car unattended. Even if it's sitting in your own driveway.