To Idle or to Turn Off the Car?

To Idle or to Turn Off the Car?

When I got my COVID-19 vac­cine, our town had a very effi­cient method of deliv­er­ing vac­cines to pas­sen­gers in a dri­ve-through set-up. Once we got the jab, we lined our cars up in a large park­ing lot to wait for 15 min­utes to watch for any adverse effects before get­ting on with our day. While lined up, I noticed that a sig­nif­i­cant num­ber of vehi­cles in the park­ing lot were idling. I was sur­prised – idling is not an effi­cient or healthy alter­na­tive to sim­ply turn­ing off your car. So why do peo­ple con­tin­ue to idle?
There is a per­sis­tent myth in the U.S. that claims it is bet­ter for your car engine and con­serves ener­gy usage to keep your car idling rather than turn it off—and yes, we are talk­ing about gas cars here.
“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,” writes the Envi­ron­men­tal Defense Fund.^{1 Like­wise, pro­longed idling can dam­age both your car and put a big­ger dent in your wal­let. You’ll spend much more mon­ey on your gas bill from wast­ed gas while idling and more for engine main­te­nance, which becomes overused when left on unnec­es­sar­i­ly.2 Final­ly, turn­ing off your engine will reduce the green­house gas impact from idled cars, includ­ing adding to the Front Range’s increas­ing­ly dire Ozone pol­lu­tion prob­lem.3 Accord­ing to Oak Ridge Nation­al Lab­o­ra­to­ry, in 2019 the annu­al U.S. fuel con­sump­tion that could be attrib­uted to idling alone was esti­mat­ed as high as 1.8 bil­lion gal­lons.4 That’s equiv­a­lent to rough­ly 16 mil­lion met­ric tons of car­bon diox­ide.5 And accord­ing to the Argonne Nation­al Lab­o­ra­to­ry, “elim­i­nat­ing the unnec­es­sary idling of per­son­al vehi­cles would be the same as tak­ing five mil­lion vehi­cles off the roads.”6}

Even dur­ing the win­ter it’s unnec­es­sary to warm up your engine for more than 30 sec­onds before dri­ving. Today’s engines are made to with­stand extreme cold (and more fre­quent restarts) and are unlike­ly to break down due to cold weath­er con­di­tions. The engine actu­al­ly warms up faster when “at-work,” rather than in park.⁷ In fact, did you know that idling for more than 5 min­utes is ille­gal in many cities across Col­orado? Be sure to check your city’s idling codes to make sure you aren’t break­ing the law by idling! Turn­ing off your engine also you to avoid sit­ting in a cloud of your own car’s exhaust, which is bet­ter for your health and doesn’t cre­ate a pol­lu­tion cloud for unsus­pect­ing pedes­tri­ans to wan­der into.

Beyond all else, there is one very sim­ple way to avoid the neg­a­tive impacts of idling – dri­ve an elec­tric car! In elec­tric cars, you can idle all you want and still avoid spew­ing exhaust fumes into the local area. Win-win!

Curi­ous to learn more about idling? Check out these fact sheets here and here.

Writ­ten by: Son­ja Meintsma