The easiest paths to sustainability offer multiple benefits – helping the environment while benefiting health and finances. Businesses refer to the “triple bottom line” when choosing options that simultaneously enhance people, profits and planet. Supporting all three “Ps” can happen on the home front as well – even with some of our most mundane daily habits.

Especially this time of year, people often let vehicles idle when starting up or when they are stopped for brief errands. The practice traces back to a time when engines required some initial idling – particularly in cold weather. But technology has changed, and it’s time for our habits to catch up.

With their characteristic candor, Ray and the late Tom Magliozzi of “Car Talk” affirmed the pointlessness of idling: “All you’re doing with a long warm-up is wasting gas, increasing pollution, raising the temperature of the planet and making yourself 10 minutes late for your … appointment.”

By one estimate, nearly 2 percent of the nation’s CO2 emissions come from vehicles that are standing stock still.

Idling burns up to half a gallon of fuel per hour in a typical car. If every U.S. driver idles six minutes a day, the fuel waste nationally totals 3 billion gallons each year, Argonne National Laboratory estimates. According to a 2009 study in Energy Policy, drivers actually average 16 minutes a day of idling! Committing not to idle saves drivers gas and money, with gains in fuel efficiency of up to 19 percent.

An idling vehicle emits 20 times more pollution than one traveling at 30 mph. Some of those emissions accumulate on driveways and roads, and get washed into local waterways. The finer particulates can settle deep in the lungs and cross into the bloodstream – causing serious cardiovascular damage. Exhaust also contains carcinogens such as benzene and formaldehyde.


Children are particularly sensitive to air pollution because they breathe more rapidly than adults, and their defense mechanisms to pollution are not yet fully developed. Roughly 10 percent of Maine children suffer from asthma, a debilitating condition aggravated by traffic-related pollution.

Recognizing this threat, the Maine Department of Environmental Protection (DEP) encourages school districts to adopt a “no idling” policy around schools for buses and personal vehicles (both of which are exempt from the State’s “anti-idling” statute).

Anti-idling legislation and U.S. Environmental Protection Agency incentives have helped reduce idling in commercial trucks. Innovations like auxiliary power units help transport and delivery trucks save fuel and greatly reduce emissions. The cost of these new systems, notes Aaron Milligan, parts manager at Portland’s O’Connor Motors, can typically be recouped within a year or two.

These new technologies help reduce engine wear, lowering maintenance costs and extending the life of the vehicle. Eliminating idling holds a similar benefit for personal vehicles. Most automobile manufacturers now advise owners not to idle for more than 30 seconds – even in cold weather. (Warming the vehicle’s oil is not an issue, the American Petroleum Institute reports, as today’s multigrade oils work well at both warm and cold temperatures.) Initial idling time can increase to a minute in bitter cold temperatures, but few vehicles require more than that (unless they have much older engines that predate electronic fuel injection).

Automobile manufacturers are moving to implement start-stop technology that will help shut down engines automatically when vehicles stop and restart them when driving resumes.

But more innovations are still needed to address the other reasons that people leave vehicles idling in the cold: defrosting windshields and raising interior temperatures. Windshields can be scraped manually, of course, but defrosters help reduce internal condensation.


Some Maine communities have enacted no-idling policies, and towns that restrict drive-through establishments benefit from less idling.

The key to change, though, lies less with statutes than with social norms, says Lynne Cayting, of DEP’s Bureau of Air Quality. Enforcement is difficult, and in many instances social marketing tools like signage and pledges can prove effective. These prompts help remind people that it’s more efficient to shut off their engines and restart them whenever they’re stopped for more than 30 seconds – whether in line at the dump or drive-through; outside the post office; in a traffic backup; or when waiting to pick up someone. The Bureau of Air Quality can supply materials to those who want to share this message in their communities.

Breaking the idling habit offers a plethora of benefits for people, profits and planet – in better respiratory health, fuel savings, engine longevity, cleaner air and water, and fewer climate-altering emissions. On the road to sustainability, it’s a clear “turnkey” solution.

Marina Schauffler, Ph.D., is a writer who runs Natural Choices (

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