American drivers spend a lot of time going nowhere, from warming up the engine to sitting in traffic or stuck at a drive-through.

Patricia Weikersheimer of the Argonne National Laboratory says that all those idling cars consume about 3 billion gallons of fuel annually.

“And that produces about 30 million tons of CO2,” she says.

But that pollution can be reduced.

Many drivers keep their engines running because they believe that restarting burns more fuel than idling. But research shows it’s usually more efficient to shut off the car.

“Idling more than 10 seconds in your passenger vehicle consumes more fuel and produces more CO2 than does turning it off and starting it back up again,” Weikersheimer says.

So she suggests that drivers turn off their engines when they’re stopped at train crossings or drive-throughs. School pickup and drop-off zones are especially important places to shut off the engine because that also reduces kids’ exposure to tailpipe pollution.

Weikersheimer says reducing idling is a zero-cost way to save fuel, cut carbon pollution, and improve air quality. And it starts with drivers asking themselves, “Do I need to have my engine on now?”

Reporting credit: Stephanie Manuzak/ChavoBart Digital Media.