Green  Transport  Partnership
 A  Glance  at  Clean Freight  Strategies:
 Idle  Reduction

             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, and

               •  provide electrical power for appliances.

             Using a heavy-duty truck engine to power cab amenities is grossly inefficient and
             causes excessive fuel use and emissions. Today's diesel engines do not need to idle
             for long periods of time before and after driving. In fact, idling often causes more
             engine damage than starting and stopping.

             Studies by Argonne National Laboratory and EPA suggest that long-haul trucks often
             idle for six to eight hours per day, over 300 days per year. Trucks consume up to one
             gallon of diesel fuel for each hour of idling, using as much as 1,000 to 3,000 gallons
             of fuel every year per truck. Unnecessary engine idling increases fuel costs and
             causes emissions that contribute to local air pollution and global warming. It also
             causes engine wear and increases truck maintenance costs.
             What's the  solution?
             Several technological options can assist drivers in reducing truck idling.
               •  An auxiliary power unit (APU) is mounted externally on the truck cab and
                 consists of a power source, such as a combustion engine, to provide electricity
                 and heat. Electricity from the APU can be used to power air conditioning,
                 heating, and electrical accessories for the cab and sleeper.
                 APUs also have the advantage of continuing to heat in
                 case of an engine breakdown while not draining battery  i£)
                 power.
                 Automatic engine idle systems (AEIS) 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 (TSE) is another option for reducing truck idling. At
                 properly equipped truck stops, drivers can simply plug trucks into outlets to
Office of Transportation and Air Quality • Mailcode? • October 2002 • EPA 420-F-02-023

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     power heaters, air-
     conditioning, marker lights,
     and other accessories. Trucks
     need to be equipped with the
     internal wiring, inverter
     system, and HVAC system
     necessary to take advantage
     of external power. This system
     is sometimes referred to as "shore power" reflecting its common use in marine
     applications.

    Advanced Truck Stop Electrification can provide heating and cooling from an
    external source. Truck parking bays are installed with systems that provide the
    cab with heating, cooling, and other amenities through an external console. 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. EPA estimates that long haul trucks typically idle 2,400 hours per
year, consuming 1,800 gallons of fuel. Using an APU instead of idling the engine will
reduce this fuel use by nearly 75 percent, saving $2,000 annually plus another $330
in maintenance costs. Using an AEIS typically reduces idling by at least 50 percent,
saving $1,350 in fuel costs and $170 in engine maintenance per year. TSE and
Advanced TSE can potentially eliminate all engine idling, although because the
systems can only be used at stations outfitted with the appropriate equipment, not all
of these savings can be realized currently. TSE pilot projects are underway in areas
where they are most useful-stops along heavily traveled freight routes.
Next  Steps
Long-haul truck fleets should examine engine operating records to determine the
percent of time spend idling. Trucks that idle more than ten percent of operating time
can likely benefit from idle reduction technologies and related driver training. More
information about idling reduction is available at EPA's website at
www.epa.gov/otaq/retrofit/idlingtech.htm or at DOE's website at
www.trucks.doe.gov/plain-talk/idling.html (DOE)
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