^SmartWay"
Transport Partnership
U.S. ENVIRONMENTAL PROTECTION AGENCY
A Glance at
Clean Freight Strategies
Idle Reduction
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 up to 1900 gallons of fuel each
year. Saving this much fuel annually would remove 19 metric tons of carbon dioxide (a greenhouse gas), reduce A/Ox
and PM emissions, save nearly $3,000 in fuel costs, and lower engine maintenance costs.
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
• generate electrical power for appliances
Studies by EPA and others suggest that long-haul
combination trucks often idle up to eight hours per
day, over 300 days per year. Typical combination
trucks consume 0.8 gallons of diesel fuel during
each hour of idling, using as much as 1,900 gallons
of fuel each year per truck.
Using a heavy-duty truck engine to power cab
amenities is inefficient. It consumes fuel
unnecessarily; increases fuel costs, and causes
emissions that contribute to climate change and air
pollution. Today's diesel engines do not need to idle
for long periods of time before and after driving.
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 idle 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.
• Truck stop electrification allows trucks to use
electrical power from an external source. At
properly equipped truck stops, drivers can
shut the main truck engine off 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 required 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, and 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
100 VAC outlet.
The results are in ...
The amount of idling varies widely among trucks by
season, type of operation, and driver practices. A
typical long haul combination truck could idle up to
2,400 hours per year, which would use over 1,900
gallons of fuel. Using an APU instead of idling the
engine could reduce this fuel use by 75 percent and
eliminate over $2,000 in fuel costs plus over $300 in
engine maintenance costs each year. 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. Additional truck stop electrification
spaces are planned along major interstate corridors.
Next steps
Truck fleets should examine engine-operating
records to determine the percent of time spent idling
to determine potential fuel and cost-saving benefits.
Truck fleets may also check the availability of truck
stop electrification facilities along frequent routes.
i.S. Environmental Protection Agency • Office of Transportation and Air Qualh
February 2004. EPA420-F-04-009. • For more Information,, visit: www.epa.gov/smartway
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