Idling Revealed

Written by Billy Karis

Each year, cars, trucks, and heavy-duty vehicles in the US waste an enormous amount of fuel running their engines while their vehicles are stationary. Also known as idling, this act effectively reduces vehicle fuel efficiency to 0 mpg and nationwide, wastes 6 billion gallons of gasoline equivalent annually (Alternative Fuels Data Center). That’s enough gas to fill 9,000 Olympic sized swimming pools, or if you were to use it to fuel a 2014 Honda Civic, you could drive it to the moon and back half a million times. More pragmatically, however, 6 billion gallons of fuel can also be represented monetarily as $21 billion.

But who is to blame for wasting all that fuel? Buses and tractor-trailers certainly contribute, but of those 6 billion gallons of wasted fuel, passenger vehicles, that you and I drive, are responsible for roughly half. Collectively, owners of passenger vehicles are throwing away more than $10 billion each year, not to mention, needlessly emitting harmful NOX, particulate matter, hydrocarbons, and carbon monoxide that lead to air quality concerns and increased incidences of smog, respiratory problems, cardiovascular disease, and even cancer. With regard to human health, the CO2 emissions are more benign, but in terms of global health, they have larger implications through the propagation of climate change.

To combat this wasteful action, improve air quality, reduce greenhouse gas emissions, and increase energy security and sustainability, the Department of Energy’s Clean Cities program has been working hard to reduce idling. In 2012, Clean Cities saved roughly 30.5 million gallons of gasoline equivalent. At $3.50/gal, that’s about $107 million and enough energy to drive a 2014 Honda Civic across the US more than 417,000 times.

While this seems like, and is in fact, an improvement, it is humbling to note that 30.5 million gallons represents only 0.5% of all the fuel wasted in the previous year. That’s a sad slice of pie.


So, what more can be done? Recent research at DOE’s Argonne National Laboratory, determined that idling for more than 10 seconds consumes more gasoline and emits more exhaust than turning off your engine and restarting it. Also, the DOE Clean Cities program reassures us that turning on and off your vehicle more frequently won’t wear out your starter. Many of these misconceptions are relics of older vehicles with finicky engines and carburetors that had to be warmed and were easily subject to flooding, but today’s high tech vehicles will undoubtedly restart. So, tap into that unused $10 billion and turn your vehicle off as you wait to pick up a friend or run in to grab your coffee.