Turning off your engine to save energy.


What activity wastes gasoline, costs tax payers money, produces pollutants, and yet doesn’t get you anywhere? Idling! And yet, every year, Americans waste 3 billion gallons of fuel by idling their vehicles.

If you started driving way back in the heyday of the carburetor, engines started up with a big gush of fuel. But unless you own an automotive dinosaur, your current engine is so efficient that idling would rarely, if ever, be an energy-friendly choice.

Idling places unnecessary wear-and-tear on the engine, and many manufacturers discourage it. Excessive idling can actually damage your engine components, including connecting rod bearings. Because of the relatively slow speed of the engine, more pressure is exerted on the bottom center and top center of the bearings. The faster the engine turns, the load gets spread out more evenly over the bearing surface.

An idling engine may not get hot enough to start the catalytic convert working or hot enough enough to run efficiently. Fuel is only partially combusted when idling because an engine does not operate at its peak temperature. This leads to the build up of fuel residues on cylinder walls that can damage engine components and increase fuel consumption. It may also load up the catalytic converter with fuel that could lead to an early demise of the catalytic converter.

  • The American Society of Mechanical Engineers (Florida section) members were asked to perform a simple experiment with their vehicles equipped with a miles-per-gallon meter.
  • They determined restarting uses approximately the same amount of gasoline as idling for 6 seconds with the A/C on.

Prime vehicles for this kind of damage are construction and maintenance vehicles. Trucks spend an inordinate amount of time idling because the driver is writing reports, observing construction work and researching proper contract compliance.

Heavy-duty vehicles, such as buses and trucks, cause even more pollution when they idle than light-duty ones. Most heavy-duty vehicles run on diesel fuel and produce many more pollutants than gasoline vehicles. Although newer diesel vehicles are cleaner than ever before, older vehicles emit large amounts of carbon monoxide (CO), oxides of nitrogen (NOx), particulate matter (PM), volatile organic compounds (VOCs), hydrocarbons (HC), and oxides of sulfur (SOx).

Did you Know:

  • Idling for 10 seconds on average uses the same amount of gas as restarting your car
  • Idling for two minutes uses the same amount of fuel it takes to go about one mile
  • Idling for 1 hour burns nearly 1 gallon of gasoline
  • The average person idles their car five to 10 minutes a day
  • Idling is linked to increases in asthma, allergies, heart and lung disease and cancer
  • Newer vehicles need no more than 30 seconds of idling time in cold temperatures
  • (Idle Free Utah and California Energy Commission)
  • In the 2008 school year 3,000 school bus drivers in Utah reduced their combined idling time by 21 minutes per day per bus. This produced an air quality benefit of preventing 5,000 lbs. of particulate matter emissions and improved our state’s air quality (2009 Energy Advisor Annual Report – PDF).

Things you can do:

  • Choosing to walk into restaurants and banks rather than using the drive-through will help improve fuel economy, reduce emissions and enhance your well-being.
  • If you must use a drive-though, consider turning off your engine while you wait.
  • Shut off your engine while waiting to pick your kids up from school
  • As gas prices rise, find ways to use gas-powered vehicles less.


  • Gov. Herbert urging motorists not to idle
  • Clear the Air Challenge – By driving less and driving smarter, you will ultimately help improve air quality, reduce traffic congestion and conserve energy in Utah. You will also be eligible for weekly and grand prize drawings by meeting straightforward, achievable travel goals.
  • Utah Moms for Clean Air – Utah Moms for Clean Air uses the power of moms to clean up Utah’s dirty air. In doing so, we are uncompromising defender’s of our children’s health.
  • SNAP works in partnership with the national Safe Routes to School (SRTS) program, which also provides funding for projects that improve student walking and biking access around schools as well as encourage and educate students to perform this healthy activity safely.  SNAP works to encourage the safety and health benefits of walking, as well as decrease air pollution and traffic congestion around schools.
  • U.S. Department of Energy’s Energy Savers Blog on Idling
  • The U.S. Department of Energy’s national Clean Cities program reduces our reliance on imported oil, saves on fuel costs, and reduces air pollution. This network of grassroots organizations includes 88 coalitions in 45 states, and consists of individuals and dozens of public and private fleets.
  • KRCL’s RadioActive! Sept 17 – Idle Free Utah



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