Idle Reduction 

A Glance at Clean Freight Strategies 

Energy & 

Fuel Savings 

Gallons Saved 

= 

1440 gallons 

Fuel Cost Savings 

= 

$5,472 

CO2 Savings 

= 

14.6 Metric tons 

Gallons Saved 

= 

960 gallons 

Fuel Cost Savings 

= 

$3,648 

CO2 Savings 

= 

9.7 Metric tons 

2400 Idling Hours 

1600 Idling Hours 

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 


$3,600 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 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 shut down after a specified period of idling time.

• 	 Direct Fired Heaters are small, lightweight, and efficient fuel-fired devices mounted in the 

. 

1 Truck fleets can exam­ 2 Truck fleets can 3 Truck fleets can 

Steps ine engine-operating determine the idle also check the availrecords to determine the reduction method that ability of truck stop percent of time spent best fits their fleets. electrification faidling to determine cilities along frequent Next potential fuel and cost- routes. 

saving benefits. 

SmartWay Transport | EPA-420-F09-038 | www.epa.gov/smartway | 734-214-4767 | smartway_transport@epa.gov 
 

Idle Reduction
 

Energy & 

Fuel Savings 

CO2 Savings 

= 

3.6 Metric tons 

Fuel Cost Savings 

= 

$1,368 

Gallons Saved 

= 

360 gallons 

600 Idling Hours 

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 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 $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 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. 

Page 2 

SmartWay Transport | EPA-420-F09-038 | www.epa.gov/smartway | 734-214-4767 | smartway_transport@epa.gov