Technologies Can Reduce Engine Idling in Large Vehicles

Engine idling is a major source of fuel inefficiency and pollution. An idling truck uses one gallon of diesel fuel per hour. Because this practice is so pervasive, it is estimated that idling heavy duty vehicles in the United States consume over one billion gallons of fuel per year. Implementation and proper use of new technologies and can help to reduce idling while still providing drivers with services and comfort currently provided by leaving the engine on. Upfront costs are most often exceeded by long-term fuel savings, but lack of investment capital and other factors have slowed technology adoption.

Drivers allow their engines to idle for various reasons. However, the rationale for doing so often does not factor in hidden economic and public consequences. A delivery vehicle may idle in a loading dock to reduce the frequency of engine starts and stops, but in fact idling takes a higher toll on the engine’s health. Rows of buses often sit idle as school lets out in order to maintain a comfortable temperature for the students, ignoring the resulting harmful exhaust pollution. Long-haul truck drivers, who rely on idling for climate control and electricity in their berths during rest periods, could cut fuel waste and preserve their engines by embracing alternative technologies and practices.

Reducing idling waste requires driver education leading to behavior change, stricter enforcement of existing state and local anti-idling laws, and wider adoption of technologies that reduce the need to idle. These technologies allow drivers to run auxiliary systems with alternative power. Electrified parking space (EPS) systems at rest areas allow long-haul drivers to connect to the local grid to power their cabs. Auxiliary power units (APU) are small on-board generators powered by diesel or a rechargeable battery and provide the benefits of an EPS system without separate infrastructure. Fuel-operated heaters (FOH) and battery air conditioning systems (BAC) offer narrower services at a lower cost, ideal for school buses and other vehicles with minimal electricity needs.

The U.S. Environmental Protection Agency’s SmartWay program evaluates and promotes idle-reduction technologies as part of its broader effort to reduce freight-sector emissions. The SmartWay Technology Program, launched in 2004, partners with freight carriers and shippers to evaluate competing products and provide incentives and recognition to those that produce and adopt approved technologies. In addition to idling reduction, the program also promotes improved aerodynamics, low-resistance tires, and retrofit exhaust filters. SmartWay provides product verification of idle-reduction technologies in eight separate categories . The program also provides guidance on state and local idling laws, opportunities to save fuel through driver behavior changes, and the impact of idling on local air quality.