Department of
Environmental Quality

DEQ's Anti-Idling Program

The Clean Air Zone Program is designed to encourage Idahoans to turn off their engines instead of idling. The program began in 2004 with a campaign aimed at encouraging school bus drivers and others not to idle on school grounds. To date, more than 300 Idaho schools and child care facilities have voluntarily joined the program.

In 2006, the program expanded to discourage vehicle idling at community facilities where idling is common, such as airports, libraries, parks, sports areas, and universities. To date, more than 30 Idaho communities have joined the program.

Subsequent efforts have focused on encouraging businesses to join the Clean Air Zone program. Businesses with delivery vans or truck fleets are great candidates for participation in the program, as are businesses with loading docks or drive-through lanes or parking lots where vendors or customers often sit and idle.

Why is Vehicle Idling a Problem?

It wastes fuel.

Idling for 10 seconds or more uses more fuel than restarting your engine. Idling for 10 minutes a day wastes an average of 26 gallons of gas per vehicle per year. People sometimes think vehicles should idle for several minutes before being driven. This is not true. Modern engines do not need more than a few seconds of idling time, even in cold weather, before they can be safely driven. In fact, the best way to warm up a car is to drive it, since that warms up the catalytic converter and other mechanical parts of the car, in addition to the engine.

It wastes money.

If fuel costs $4 a gallon, idling for 10 minutes a day costs $104 per vehicle per year. Even at $3 a gallon, you're still wasting $78 per vehicle per year.

It pollutes the air.

Vehicles emit many pollutants into the air. Compared to the smokestack image many people associate with air pollution, emissions from an individual car may seem insignificant. Emissions from many vehicles on the road or idling in a waiting area add up, however, and can have a serious impact on air quality.

It's harmful to our health.

Breathing elevated levels of air pollutants can adversely affect human health, especially in sensitive populations such as children, the elderly, and people with certain health conditions such as asthma.

It can damage our vehicle's engine.

Cylinders, spark plugs, and exhaust system are at risk. Idling an engine forces it to operate in a very inefficient and gasoline-rich mode that, over time, can degrade the engine’s performance and reduce mileage.

Five Easy Ways You Can Help Control Air Pollution from Vehicle Emissions

1. Drive less. This is the single most effective way to reduce vehicle emissions. Ride the bus, carpool, share trips, walk, bike, or use some other form of alternative transportation whenever possible. Combine trips to the same areas.
2. Turn off your engine when waiting. Avoid idling if you will be sitting in your car longer than 10 seconds. You can also reduce emissions and save fuel by minimizing use of the vehicle’s air conditioner.
3. Drive at a medium and steady speed. Try to “smooth” your driving by accelerating and decelerating gradually, and anticipating stops and starts for traffic lights, changing traffic speeds, and so on. Most cars get the best gas mileage at between 35 and 45 miles per hour. Higher speeds result in greater emissions.
4. Get regular tune-ups. Vehicles with worn spark plugs or clogged fuel or air filters do not run efficiently which causes them to emit more pollution. Poorly maintained or malfunctioning vehicles can release as much as 10 times the emissions of a well-maintained one.
5. Consider purchasing a low-emissions vehicle. Check the posted fuel-efficiency rating. The greater the efficiency, the lower the emissions per mile.