SmartWay
U.S. Environmental Protection Agency +
Idle Reduction
A Glance at Clean Freight Strategies
ENERGY & FUEL SAVINGS
1600
Idling Hours
Gallons Saved:
960 gallons
CO2 Savings:
9.8 metric tons
Fuel Cost Savings:
$2,790
1000
Idling Hours
Gallons Saved:
600 gallons
CO2 Savings:
6.1 metric tons
Fuel Cost Savings:
$1,745
Reducing unnecessary truck idling can save fuel, reduce greenhouse gas emissions, cut
air pollution, and save money. A typical long-haul combination truck that eliminates
unnecessary idling could save over 900 gallons of fuel each year. Saving this much
fuel annually would effectively remove 9 metric tons of carbon dioxide, reduce nitrogen
oxide and particulate matter emissions, save $2,790 in fuel costs, and lower engine
maintenance costs for the truck.
WHAT IS THE CHALLENGE?
Many long-haul truck drivers idle their engines during rest periods to:
Provide heat or air conditioning for the sleeper compartment
Keep the engine warm during cold weather to avoid trouble with cold starts
Generate electrical power for appliances
Studies by EPA and others suggest that long-haul combination trucks often idle overnight
between 5 and 8 hours per day, over 200 days per year. Typical combination trucks
consume about 0.8 gallons of dieselfuel during each hour of idling, using between 350
and 900 gallons of fuel each year per truck.
Today's diesel engines do not need to idle for long periods of time before and after driving.
Using a heavy-duty truck engine to power cab amenities is inefficient. It consumes fuel
unnecessarily, increases fuel costs, and generates emissions that contribute to climate
change and air pollution. Unnecessary engine idling also contributes to engine wear, which
increases truck maintenance costs, and shortens engine life.
WHAT IS THE SOLUTION?
Several technological options can assist drivers in reducing truck idling:
Auxiliary Power Units (APUs) are mounted externally on the truck cab. An APU
typically consists of a small combustion engine and generator combination that can
provide power to the truck when the main engine is shut off. Electricity from an
APU can be used to power heating, air conditioning, and electrical accessories for
the cab and sleeper.
Automatic Engine Shutdown Systems start and stop the truck engine automatically
to maintain a specified cab temperature or to maintain minimum battery charge.
Drivers typically activate the system in the evening and program a desired
temperature range. Drivers can also program the system to shutdown after a
specified period of idling time.
Direct Fired Heaters are small, lightweight, and efficient fuel-fired devices mounted
in the cab of a truck. The direct fired heater provides heat for driver comfort in the
cab. This technology does not include any air conditioning capabilities.
%

EPA-420-F-19-0211 August 2019 | SmartWay Transport Partnership | epa.gov/smartway
(continued)

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Idle Reduction: A Glance at Clean Freight Strategies (continued)
Idling Hours
Gallons Saved:
360 gallons
CO2 Savings:
3.7 metric tons
Fuel Cost Savings:
$1,050
Truck Stop Electrification allows trucks to use electrical power from an external
source. At properly equipped locations, drivers can shut off the main truck engine
and plug into an electrical outlet that provides power for heaters, air conditioners,
marker lights, and other accessories. Trucks need to be equipped with the
appropriate internal wiring, inverter system, and HVAC system to take advantage
of truck stop electrification.
Advanced Truck Stop Electrification also provides electricity from an external
source, but doesn't require the truck to be equipped with special systems. Truck
parking bays are installed with equipment that provides the cab with electrical
power, heating, cooling, and other amenities like telecommunication hook ups,
through an external console that fits into the truck's window frame. The truck-side
console has temperature controls, an air supply and return pipe, a credit card
reader, keypad, and a 100-Volt AC outlet.
SAVINGS AND BENEFITS
The amount of idling varies widely among trucks by season, type of operation, and driver
practices. A typical long-haul combination truck can idle between 1,600 and 2,400 hours
per year, which would use about 900 and 1,400 gaLLons of fuel, respectively. Saving fuel
annually through idle reduction by installing an APU would remove about 9 to 14 metric
tons of carbon dioxide, reduce nitrogen oxide and particulate matter emissions, save
between $2,800 and $4,200 in fuel costs, and lower engine maintenance costs. A short-
haul truck can save 360 gaLLons per year, saving $1,050 when using an idle reduction
technology. Truck stop electrification can potentially eliminate all engine idling. However,
because the systems can be used only at stations outfitted with appropriate equipment,
not all the potential savings can be obtained immediately.
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Truck.fleets can examine engine-operating records to determine the percent of time spent idling to
determine potential fuel and cost-saving benefits.
Truck fleets can determine the idle reduction method that best fits their fleets.
Truck fleets can also check the availability of truck stop electrification facilities along frequent routes.

Please visit the SmartWay website at www.epa.gov/smartway
to access more tech bulletins.
SmartWay
U.S. Environmental Protection Agency^

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