Idle reduction, or limiting the amount of time that vehicles idle unnecessarily, can be a key strategy for increasing fuel efficiency and reducing petroleum use. The Vehicle Technologies Office supports research on idle reduction and provides a variety of technical resources to help fleets and individuals reduce idling.

Research and Development

As part of its broader efforts to improve heavy-duty fuel efficiency, VTO supports research on idle reduction technology. All four teams participating in the SuperTruck project aimed at improving the freight efficiency of Class 8 long-haul vehicles by 50 percent are using idle reduction approaches in their vehicles. One team is using lithium-ion batteries (charged by the engine) to run its air conditioning, heating, and electronics during mandated rest stops. Others are hybridizing the entire truck with an electric drive system.

Idle Reduction Resources

There are a number of other government resources available to learn more about idle reduction technologies:

To start an idle reduction campaign at your organization, contact your local Clean Cities coalition. The coalition can support your efforts with IdleBox, an electronic, modular toolkit to help light- and medium-duty fleet managers of save money, support a cleaner environment, and receive recognition.

A number of state and federal programs offer incentives for idle reduction projects and equipment. The AFDC's Laws and Incentives Database and EPA's regional Diesel Collaboratives offer information about financial incentives, grant and loan programs.

Idle Reduction Policies

Many states and municipalities restrict idling and/or provide weight exemptions for freight vehicles using idle reduction equipment.

  • The map above describes the laws surrounding weight exemptions for freight vehicles using idle reduction equipment.
  • VTO's IdleBase contains information about known laws for all classes of on-road vehicles. If your state, county, or municipality has made or is proposing changes, please let us know.
  • The American Transportation Research Institute (ATRI) provides a database of anti-idling laws specific to heavy-duty vehicles only.

In addition, the federal government allows states to adopt weight exemptions for freight vehicles using idle reduction equipment. The Energy Policy Act (EPAct) of 2005 allowed for a national 400-pound exemption. In 2012, the Moving Ahead for Progress in the 21st Century (MAP-21) increased this weight allowance from 400 lb to 550 lb. Each state can adopt either exemption at its own discretion.