SmartWay*
MENTAL PROTECTION AGENCY »
U.S. ENVIRONMENTAL PROTECTION AGENCY
Idle Reduction
A Glance at Clean Freight Strategies
ENERGY &
FUEL SAVINGS
2400 Id/ing Hours
Gallons Saved:
1440 gallons
CO2 Savings:
14.6 metric tons
Fuel Cost Savings:
$5/472
1600 Idling Hours
Gallons Saved:
960 gallons
CO2 Savings
9.7 metric tons
Fuel Cost Savings:
$3,648
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 9OO 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 $3,6OO 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 300 days per year. Typical combination trucks consume about 0.8
gallons of diesel fuel during each hour of idling, using between 900 and 1,400 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 auto-
matically 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.
• 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 acces-
sories. Trucks need to be equipped with the appropriate
internal wiring, inverter system, and HVAC system to take
advantage of truck stop electrification.
Continued
U.S. EPA SmartWay | EPA-420-F-16-025 | June 2016 | www.epa.gov/smartway
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SmartWay*
MENTAL PROTECTION AGENCY »
U.S. ENVIRONMENTAL PROTECTION AGENCY
Idle Reduction
A Glance at Clean Freight Strategies
Continued
ENERGY &
FUEL SAVINGS
600 Idling Hours
Gallons Saved:
360 gallons
CO2 Savings:
3.6 metric tons
Fuel Cost Savings:
$1,368
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 1 00-Volt
AC outlet.
Savings and Benefits
The amount of idling varies widely among trucks by season, type of operation, and driver
practices. Atypical 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 $3,600 and
$5,500 in fuel costs, and lower engine maintenance costs. A short-haul truck can save 360
gallons per year, saving $1,300 when using an idle reduction technology. Truck stop electrifi-
cation 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.
N1EX1 ST-PS
1 Truck fleets can
examine engine-
operating records to
determine the per-
cent of time spent
idling to determine
potential fuel and
cost-saving benefits.
2Truck fleets can
determine the idle
reduction method
that best fits their
fleets.
3Truck fleets can
also check the
availability of truck
stop electrification
facilities along
frequent routes.
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