Idling Facts

Annual cost of

light-duty idling

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Idling is money out the tailpipe


Fuel waste: Whether a light-duty car, SUV or pickup, or commercial truck, needless idling burns hard earned dollars or company profits through the tailpipe. Think about it: an idling vehicle gets negative MPG. Even at current low fuel prices, an averaged sized car, like a Subaru Outback, will cost you more than $100 annually in excessive, unnecessarily long warm ups.


Engine wear: According to several reliable sources, including the comprehensive 2013 study: Oak Ridge National Laboratory Summary of OEM Idling Recommendations from Vehicle Owner’s Manuals, "Excessive idling can create engine wear and carbon soot buildup in the engine and components". This can lead to increased engine maintenance and shortened engine life for light-, medium-, and heavy-duty vehicles. For similar reasons, many owners manuals recommend avoiding excessive idling. Excessive idling causes adhering to a "severe duty" maintenance schedule.


Calculate your idling reduction fuel savings!

Annual cost of

heavy-duty idling

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Idling exhaust chemicals negatively impact our health

Health impact: light-duty gasoline & diesel: Modern light-duty internal combustion engine vehicles, despite emissions controls, still emit harmful levels of exhaust chemicals, such as carbon monoxide (and carbon monoxide poisoning), nitrogen oxide, sulfur dioxide, hydrocarbons, and benzene. These emissions are more toxic during idling, particularly during hot and cold weather extremes.

Gasoline Engine Emissions and Health fact sheet from the American Lung Association in Vermont.


Health impact: medium- & heavy-duty diesel: Many commercial vehicles and school buses are equipped with diesel engines. They are durable and economical sources of power. And the good news is that newer diesels are 90% cleaner than those manufactured prior to 2007. But older diesels -- which can last 20 years or more -- contain toxic exhaust components such as particulate matter, nitrogen oxides and volatile organic compounds that cause significantly higher levels of harmful emissions when idling. The Union of Concerned Scientists webpage, Diesel Engines and Public Health has comprehensive information on the Health Impacts of Diesel Pollution.


Overall health impact: Prolonged exposure of these emissions can cause cancer over time, exacerbate heart conditions, and cause or exacerbate asthma. Children and the elderly are especially vulnerable. Vermont does not escape these exposures, indeed, with the third highest rate of adult asthma in the nation.

VIDEO: Dr. Gerald Davis, UVM Lung Specialist and Pulmonologist, talks about the importance of going "Idle-Free".

Idling GHG emissions contribute to climate change


Greenhouse gas emissions from heavy-duty and light-duty vehicles alike, including carbon dioxide (CO2), contribute to climate change. The world's scientists tell us that 350 parts per million CO2 in the atmosphere is the safe limit for humanity. But in January 2019 we are at 410 ppm.


Overwhelming scientific evidence, including from the Intergovernmental Panel on Climate Change (IPCC), the National Aeronautics and Space Administration (NASA),  and the National Oceanic and Atmospheric Association (NOAA) link climate change to the earth's warmest global temperatures, melting polar ice caps, rising sea levels, increasingly severe weather events, droughts, wildfires, flooding, and to the threat of many plant and animal species. See how climate change is impacting Vermont with rising high and low temperatures, rising average temperatures, more intense storms, more total percipitation, less snow cover, and shorter winters.


Even the Pentagon is assessing the risk of climate change, stating, "The effects of climate and extreme weather represent additional risks to incorporate into the Department’s various planning and risk management processes. Various studies have identified a broad range of effects that could impact our ability to fully execute the Defense mission of protecting and

maintaining the security interests of the United States at home and around the world."


- According to a University of Vermont Transportation Research Center 2014 passenger vehicle idling report, Vermonters idle vehicles voluntarily (while parked) for 9.6 million hours annually, equating to emitting 36,500 metric tons of CO2e into the atmosphere. This does not even include heavy-duty trucks and buses.


In 2015, of Vermont's greenhouse gas emissions, transportation is by far the largest factor at 43% while nationally it is 28%.

What is "Auto Stop-Start"?


Auto stop-start technology (also known as start-stop) is an alternative to hybrid technology that helps to conserve 5-10% in fuel economy by automatically shutting off the engine (eliminating idling) when a vehicle comes to a stop, such as at stoplights. The engine automatically restarts when the driver takes his or her foot off the brake. During engine shutoff, an auxiliary 12-volt battery powers electric accessories such as heating and air conditioning, power windows and radio.


For 2016, stop-start was offered in only a handful of American vehicles such as the Chevy Malibu and Cruze, Cadillac CT6, Ford Edge, F-150 and Fusion, Dodge Ram 1500 HFE, plus some BMW models. But by 2020, we can expect up to one-half of all vehicles to be equipped with it.


Update: As of 2017, 15% of new vehicles are equipped with stop-start. Note however that manufacturers are including a disable button on some models.


To learn more about auto-stop start, watch this video from Johnson Controls, a manufacturer of this system.

Idling contributes to fossil fuel use


Many of us are aware of conserving and saving energy. We're in the habit of turning off lights when leaving a room, and we know about recycling beverage containers. Turning off the keys of our parked vehicles is a great energy conserving habit to get into.


The U.S. Dept. of Energy states, "Each year, U.S. passenger cars, light-duty trucks, medium-duty trucks, and heavy-duty vehicles consume more than 6 billion gallons of diesel fuel and gasoline—without even moving. Roughly half of that fuel is wasted by passenger vehicles." And according to a comprehensive study on the idling of just passenger vehicles conducted by Vanderbilt University, voluntary idling alone (idling when parked) in the U.S. accounts for about 1.8 billion gallons of fuel used annually. [Page 5, Table 3 of study]


According to a University of Vermont Transportation Research Center 2014 passenger vehicle idling report, it is estimated that Vermonters idle vehicles voluntarily (while parked) for 9.6 million hours annually, consuming 4.1 million gallons of fuel (based on passenger vehicle — car/SUV/light-duty truck — idling consumption of 0.43 gal/hr). This does not even include heavy-duty trucks and buses.


Most gasoline is derived from crude oil, a non-renewable resource. While the threat of depletion of oil has lessened ­— as North America slowly transitions from exporting foreign "conventional" petroleum to the extraction of "unconventional" petroleum (primarily using the method of hydraulic fracturing or "fracking") — the critical challenge of the future remains to transition from fossil fuels to clean, renewable forms of energy. Why? Unconventional oil is much harder to extract making it more expensive, much dirtier (tar sands, aka oil sands or bituminous oil), more environmentally harmful (fracking process and threat of pipeline spills), and will increase the challenge of tackling the global climate crisis. Oil will always be harmful to humans and our planet, from extraction through emissions.

Vermont has laws that restrict idling


• The State of Vermont Prohibited idling of motor vehicles law limits idling of all motor vehicles while parked to five minutes in any 60-minute period, with exceptions.


Vermont's school bus idling rule restricts the idling of school buses on school grounds. There is also an option in the law for school boards in each district to adopt idling policies for motor vehicles other than school buses (employees, students, parents, delivery, etc.) when present on school grounds.


23 V.S.A. § 1111. Unattended motor vehicle prohibits allowing a vehicle's engine to run while unattended in public.


23 V.S.A. § 1222a. Emissions of diesel-powered commercial vehicles (aka Smoky Truck Law): Observe a commercial truck spewing black soot from the exhaust? It may be stopped and an inspection performed if it appears vehicle exhaust exceeds standard.


• The City of Burlington has an idling restriction ordinance (Chapter 20 Motor Vehicles and Traffic > 20-55 General Prohibitions - scroll to (e) ).


For more details on idling laws, visit the Idling Laws page.