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Tools for Fleet Managers

to reduce idling by police vehicles, ambulances, fire trucks, and other fleet vehicles

Much of the following information is provided by the Department of Energy. Public fleets, including police cars, ambulances, and fire trucks, along with other service vehicles such as armored cars, are often exempt from laws that limit engine idling. However, these vehicles can save fuel and reduce emissions with technologies that allow them to perform vital services without idling.

The Problem with Fleet Idling

Ambulance engines are idled to maintain lighting, communications equipment, computers, refrigeration for medication, and life-support equipment, as well as the vehicle’s heating and cooling systems. Idling these diesel engines outside hospital emergency rooms while the drivers complete paperwork and await their next call not only wastes fuel but produces significant air pollution that can exacerbate respiratory or cardiovascular problems in sensitive populations.

Police cruisers spend much of their time parked and running while officers monitor traffic, help at accident scenes, write reports, and wait to be called. Officers commonly require lights, radios, computers, radar, and video cameras.

Studies have found that police cruisers may idle up to 60% of the time during normal operation.

When fire engines and trucks are dispatched, only about 20% of the calls are for fires; most are for medical emergencies or accidents. For any call, the vehicle is often idled to provide power for emergency lights and other accessories. Both battery-powered and diesel APUs can reduce fuel use, emissions, and noise for nonfire calls. These APUs, which can be factory-installed or installed as a retrofit, can supply power for all services, except for water pumping, which requires additional power.

Tools to Reduce Fleet Idling

Calculate Potential Cost Savings

Idling fleets not only releases harmful pollution, but can also waste enormous amounts of fuel and money. In one report about police vehicle fuel consumption, the cruiser studied was found to idle 60% of the time during normal operation and used 21% of its total fuel while parked. While the engine provided 250 horsepower (hp), together all of the accessories needed less than 2 hp (air conditioning consumed the most power, followed by external lighting).

You can calculate the amount of money being wasted by idling fleet vehicles – as well as potential cost savings – by using the Argonne Labs Idle Reduction Calculator. It’s possible that the money saved from investing in anti-idle technology could pay itself back in cost savings from less fuel usage. For example, when the Burlington, VT police department installed a $500 IdleRight Fuel Management System on a police cruiser, the department showed that the device was capable of saving 345 gallons of fuel and decreasing operating costs by about $811 per vehicle annually. This device also reduced wear and tear on the vehicles engine, and crucially, tailpipe emissions.

Adopt Anti-idling Policies

The best way to prevent idling is to transition to electric or hybrid vehicles.  However, until public fleets are able to transition away from solely internal combustion engines, fleet managers can adopt an anti-idling policy, and use it to educate drivers about the downsides of idling.

Adopt Anti-Idling Technology

Another way to reduce idling, especially when it’s being done to power equipment, is to invest anti-idling technology. Several idling-reduction systems, with varying capabilities and costs, are available for vehicles. Power-management systems may significantly reduce (but not eliminate) idling. They allow the vehicle’s battery to power auxiliaries in engine off mode and monitor the battery’s state-of-charge. When the battery charge falls below a preset threshold, the system restarts the vehicle’s engine to recharge the battery. Another option is a heat-recovery device, which uses a small pump to circulate coolant from the warmed engine, providing heat to the passenger compartment after the engine has been turned off. Battery auxiliary power units (APUs) are another option for vehicles. These units store power when the engine is running and supply it to the vehicle’s electrical devices for 4 hours or more when the engine is off.

For ambulances, on-board battery-powered APUs that can supply power for all needed functions are available. Drivers can plug in the APU to charge at the hospital, or the vehicle engine can charge it while the ambulance is being driven. Solar panels can be installed on the roof to provide additional power. Stationary systems can be installed near the emergency room to enable ambulances to plug in for power and receive conditioned air through a window duct. Fire trucks can also be use battery-powered or diesel APUs to reduce fuel use, emissions, and noise for nonfire calls. These APUs, which can be factory-installed or installed as a retrofit, can supply power for all services, except for water pumping, which requires additional power.