Report published: February 2009
Idling is when a driver leaves the engine running and the vehicle parked. Every day in the U.S., millions of cars and trucks idle needlessly — sometimes for hours — and an idling car can release as much pollution as a moving car.
You may not be able to avoid keeping your engine running when you're stopped at a traffic signal or stuck in slow-moving traffic. But other times idling is unnecessary.
Four ways to be idle-free
- Turn off your ignition if you're waiting more than 10 seconds. Contrary to popular belief, restarting your car does not burn more fuel than leaving it idling. In fact, idling for just 10 seconds wastes more gas than restarting the engine.
- Warm up your engine by driving it, not by idling. Today's electronic engines do not need to warm up, even in winter. The best way to warm the engine is by easing into your drive and avoiding excessive engine revving. After just a few seconds, your vehicle is safe to drive. The vehicle's engine warms twice as quickly when driven.
- Warm up the cabin interior by driving, not idling. Easing into your drive is also the best way to get your vehicle's heating system delivering warmer air faster. Sitting in an idling car means you are breathing in more of the dirty exhaust that leaks into the car cabin. Any warmth you may get from a car heater is not worth the damage to your health. If parked and waiting, it is healthier to get out of your car and go inside a store or building.
- Protect your car engine by idling less. Frequent restarts are no longer hard on a car's engine and battery. The added wear (which amounts to no more than $10 a year) is much less costly than the cost of wasted fuel (which can add up to $70-650 a year, depending on fuel prices, idling habits and vehicle type). Idling actually increases overall engine wear by causing the car to operate for longer than necessary.
Reasons to stop idling
A simple turn of your key can keep the air cleaner and save money and fuel. Every time you turn off your car engine in place of idling, you'll:
- Make the air healthier by cutting down on hazardous pollution in your town or community. Idling tailpipes spew out the same pollutants as moving cars. These pollutants have been linked to serious human illnesses including asthma, heart disease, chronic bronchitis, and cancer.
- Help the environment. For every 10 minutes your engine is off, you'll prevent one pound of carbon dioxide from being released (carbon dioxide is the primary contributor to global warming). An EDF report shows that in New York City alone, idling cars and trucks produce 130,000 tons of carbon dioxide each year. To offset this amount of global warming pollution, we would need to plant an area the size of Manhattan with trees every single year.
- Keep money in your wallet and save fuel. An idling car uses between 1/5 to 7/10 of a gallon of fuel an hour. An idling diesel truck burns approximately one gallon of fuel an hour. With average U.S. prices for diesel fuel topping $2 a gallon1, that's about $2 an hour wasted.