||The examples and perspective in this article deal primarily with the United States and do not represent a worldwide view of the subject. (October 2012)|
Idle reduction describes technologies and practices that minimize the amount of time drivers idle their engines. Avoiding idling time has a multitude of benefits including: savings in fuel and maintenance costs, extending vehicle life, and reducing damaging emissions. Recently[when?], the World Health Organization (WHO) labeled diesel emissions a carcinogen, and it estimated that approximately 1.5% of cancer deaths are attributed to air pollution.
Idle reduction equipment (vehicle emissions control) is aimed at reducing the amount of energy wasted by idling trucks, rail locomotives or automobiles. When a vehicle's engine is not being used to move the vehicle, it can be shut off entirely — thereby conserving fuel and reducing emissions— while other functions like accessories and lighting are powered by an electrical source other than the vehicle's alternator. Each year, long-duration idling of truck and locomotive engines emits 11 million tons of carbon dioxide, 200,000 tons of oxides of nitrogen, and 5,000 tons of particulate matter into the air.
In the public sector, idling is common. Police officers, public works employees, fire fighters, and EMTs who operate city fleet vehicles run them at idle to perform their duties which require them to operate radios, emergency lights, laptops, digital cameras, license plate readers, or powering equipment, power tools and hydraulics. The emissions generated from these tasks by cities all over the U.S. contribute to the fact that each year U.S. passenger cars, light trucks, medium-duty trucks, and heavy-duty vehicles consume more than 6 billion gallons of diesel fuel and gasoline — without even moving. As fuel prices continue to rise, a major challenge in fleet management is how to keep service vehicles on the road to serve the public while staying within budget.
Idle reduction is particularly significant for vehicles in heavy traffic and trucks at the estimated 5,000 truck stops in the US. Many hybrid electric vehicles employ idle reduction to achieve better fuel economy in traffic. America's fleet of around 500,000 long-haul trucks consumes over a billion gallons (3.8×109 l; 830 million imp gal) of diesel fuel per year. The trucking industry has analyzed the impact of idling on engines, both in terms of maintenance and engine wear costs. Long-duration idling causes more oil and oil filter deterioration and increases the need for more oil and filter changes. Similarly, the longer the idling time, the sooner the engine itself will need to be rebuilt. The trucking industry estimates that long duration idling costs the truck owner $1.13 per day, based on the need for more frequent oil changes and sooner overhaul costs. Services such as AireDock, IdleAire and Shorepower provide power at truck stops to resting truckers who would otherwise need to continue idling during mandatory breaks. Because the United States Department of Transportation mandates that truckers rest for 10 hours after driving for 11 hours, truckers might park at truck stops for several hours. Often they idle their engines during this rest time to provide their sleeper compartments with air conditioning or heating or to run electrical appliances such as refrigerators or televisions.
There are other technologies that can reduce the use of fuel to heat or cool the cab when the vehicle is traditionally idling overnight. These can be battery or fuel powered but in either case, use less fuel, do no harm to the vehicle's engine, and add far fewer or even no additional emissions into the atmosphere. Vehicles other than long haul trucks, including police, military, service trucks, news vans, fire trucks, ambulances, and hydraulic bucket trucks can be equipped and retrofitted with mobile power idle reduction systems, similar to a rechargeable battery. The systems are usually installed in the trunk and can provide up to 10 hours of additional power for equipment operation without engine engagement. When used by law enforcement and the military, idle reduction technology increases mission capability by extending operational time and providing increased situational awareness and safety. Mobile power idle reduction systems are manufactured by Energy Xtreme and Kohler.