"Idling" means to run your vehicle engine when it’s parked or not in use. Common reasons for engine idling are warming up the vehicle, personal comfort, waiting for someone, listening to the radio, or convenience. There are many reasons NOT to idle. By reducing idling time you save fuel and money, reduce wear and tear on your engine, help protect your health, and reduce climate change impacts. Learn how to reduce your idling time.
New Hampshire regulations (Env-A 1100) help to minimize the impact from engine idling and reduce exposure to exhaust emissions by establishing a limit on the amount of time that engines are permitted to idle. Of course, this is the maximum time limit so you should always turn your engine off as soon as possible when parked or stopped. The limit established in the regulations is based on outside temperature, as follows:
| Temperature | Maximum Idling Time Limit |
|---|---|
| Above 32º F: | 5 minutes |
| Between –10º and 32º F: | 15 minutes |
| Below –10º F: | no limit |
Certain vehicles are exempt from the regulation. Those exemptions include vehicles in traffic, emergency vehicles, vehicles providing power take-off (PTO) for refrigeration or lift gate pumps, and vehicles supplying heat or air conditioning for passenger comfort during transportation.
Some Facts and Figures to Help You Think About Idling
- Thirty seconds of idling can use more fuel than turning off the engine and restarting it. If you are stopped for more than 30 seconds, except in traffic, turn off your engine.
- Idling gets you nowhere. Idling equals zero miles per gallon. An idling vehicle is the most inefficient vehicle on the road.
- Idling is not an effective way of warming up your engine. As your vehicle is made up of many moving parts, to properly warm your vehicle’s transmission, tires, suspension, steering, and wheel bearings, you need to slowly drive off.
- One hour of idling burns a half to a full gallon of fuel. Idling for 10 minutes uses as much fuel as traveling five miles. For example: Reduce idling 10 min./day for a year and you save approximately $244! [10 min./day x 365 days = 3650 min./yr., or 61 hour/yr. At 1 gal./hr., that means you waste 61 gal./yr., and at $4/gal, that equals $244!]
- Every gallon of gas burned produces about 20 pounds of carbon dioxide, a major contributor to climate change. For example: Reduce idling by one hour per day, you would save 3.65 tons of carbon dioxide emissions in a year. [1 gal./hr. x 20 lbs./gal. x 365 days = 7,300 lbs./yr. or 3.65 tons/yr.]
- Consuming less fuel by not idling helps to reduce the need to import oil to meet demands. Saving gasoline (a fossil fuel) represents conservation of a non-renewable natural resource.
- Idling releases unhealthy exhaust fumes, including particulates, carbon monoxide (CO), nitrogen oxides (NOx), and volatile organic compounds (VOCs). Breathing exhaust fumes increases the risk of cancer, heart and lung disease, asthma, and allergies, especially in children.
- Exposure to most auto pollutants can often be higher inside vehicles than outside. By eliminating unnecessary idling, drivers can protect their health and that of their passengers.
Reduced idling time saves fuel and money!
Reduced idling helps protect your health!
Reduced idling helps lessen climate change impacts!
Diesel Idling Initiative
Drivers of heavy duty diesel vehicles can have a significant impact on public health and the environment by limiting engine idling time whenever possible. Emissions from idling trucks and buses contribute to air pollution and haze and may affect drivers’ health, as well as the health of the general public. Idling also consumes a significant amount of fuel, adds wear and tear to the engine, and ends up costing diesel vehicle drivers thousands of dollars each and every year!
The American Trucking Association (ATA) reports that engine idling not associated with normal driving makes up as much as 30 percent to 50 percent of truck operating hours. The ATA estimates that engine wear caused by idling one hour every day is equivalent to driving 64,000 miles per year. Idling not only wears the engine and leads to higher maintenance and repair costs, but it also reduces fuel economy. Idling consumes one gallon of fuel per hour, resulting in close to a billion gallons of diesel fuel wasted each year nationwide!
Diesel vehicle fleets and drivers can help improve air quality and public health by complying with the regulations and by proactively adopting and promoting policies to further minimize engine idling. (See the link under "Education and Outreach" for sample policies.) This effort will not only reduce exposure of truck and bus drivers and others to the harmful pollutants in diesel exhaust, but it will also help improve air quality and reinforce these drivers’ image as "good neighbors."
Alternatives to idling exist when cab comfort is a concern for truck operators during summer and winter months. For example, "anti-idling devices" include direct-fired burners for cab and engine block heating; thermal storage devices for heating and cooling electrified truck steps; and auxiliary power units for heating, cooling, and electrical power. These units use only 10 percent to 15 percent of the fuel a diesel truck engine uses and also emit much less air pollution per gallon burned. They are commercially available, easy to install, efficient, and relatively inexpensive to operate. Anti-idling devices can also save the average long haul truck driver as much as $4,000 each year in fuel costs alone. Less idling time means less wear on the engine, which saves on preventative maintenance and repair costs. Information on cab comfort units is provided at the EPA web site under Technical Assistance.
School Bus Anti-Idling Initiative
Air pollution from diesel vehicles has health implications for everyone, but children are more susceptible to this pollution because their respiratory systems are not fully developed. Diesel exhaust typically contains particulate matter (PM), hydrocarbons (HC), and carbon monoxide (CO). Exposure to fine particles in school bus exhaust can result in increased frequency of childhood diseases, such as asthma. At school yards, idling school buses release emissions directly into the breathing zone of children. As children line up to board an idling bus, they are exposed to the vehicle’s emissions at the most concentrated levels. Limiting the amount of idling time not only reduces exposure of school students to the harmful pollutants in diesel exhaust, but it also improves air quality.
In 2002 DES teamed up with the New Hampshire School Transportation Association (NHSTA) to launch a voluntary initiative to protect school children and bus drivers from excessive exposure to exhaust emissions from school buses. As part of the initiative, fleet managers and school bus drivers throughout New Hampshire are encouraged to adopt policies and practices to reduce school bus engine idling time whenever possible. This initiative has been expanded to include the whole school community. School officials are encouraged to turn their school yards into "Clean Air Zones" by establishing no idling policies for all drivers who enter the school area - bus drivers, parents, teachers, student drivers and delivery vehicles.