Is idling cheaper than switching my car on and off?

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.