Transport Partnership
U.S. ENVIRONMENTAL PROTECTION AGENCY
Energy &
Fuel Savings
Aerodynamic Long Haul
Combination Truck
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Gallons Saved
1,651 gallons
CO2 Savings
16.7 Metric tons
Increase in Fuel
Economy
NewMPG
(original 6 mpg)
6.6 mpg
Fuel Cost Savings
Improved Aerodynamics
A Glance at Clean Freight Strategies
Using a streamlined-profile tractor with aerodynamic devices can improve
fuel economy by over 3 percent and will reduce fuel costs by over $2,000. When
adding an aerodynamic trailer, you can get up to an II percent increase in fuel
economy, saving 16 metric tons of carbon dioxide.
What is the challenge?
Aerodynamic drag (wind resistance) accounts for most truck energy losses at highway
speeds. Reducing drag improves fuel efficiency. The longer the drive and the higher the
speed, the greater the potential efficiency benefits become. Manufacturers have made signifi-
cant progress over the past two decades in reducing the drag coefficient (a measure of wind
resistance) of a typical freight truck from about 0.8 to about 0.65 - an improvement of nearly
20 percent. Additional efforts to improve aerodynamics could result in a further 25 percent
reduction in the drag. This could have a significant impact on fuel economy. For example,
cutting drag by 20 percent could boost fuel economy up to 15 percent at highway speed.
What is the solution?
A number of options exist to improve aerodynamics and improve fuel efficiency.
Tractor Aerodynamics
Truck tractor aerodynamic options:
Roof fairings (an integrated air deflector mounted on the top of the cab)
Side extender fairings (to reduce the gap between the tractor and the trailer)
Side tank fairings
Aerodynamic front bumper (to reduce air flow beneath the truck).
Aerodynamic mirrors
Truck manufacturers offer aerodynamic models that include a streamlined front profile,
sloped hood, and a full package of add-on devices. Selecting these features for a typical trac-
tor model can improve fuel economy by over 3 percent. However when improving a classic
combination truck with no aerodynamic features, one can see up to a 15 percent increase in
fuel economy.
$6,276
Q.
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Automatic Tire Inflation Systems
Trailer Aerodynamics
Truck trailer aerodynamic options:
Gap Reducer (these devices affixto the front of the trailerto minimize the gap between the tractor and trailer,
minimizing air turbulence in turn)
Side Skirts (these panels hang down from the sides of a trailer at the bottom edge to enclose the open space
between the rear wheels of the tractor and the rear wheels of the trailer)
Cargo Configuration (reduce drag by arranging cargo as low and smooth as possible)
Wheelbase and fifth-wheel settings (positioning the trailer as close to the rear of the tractor as possible ton reduce
tractor-trailer gap). For freight carried on flat bed trailers, securing loose tarpaulins and closing the curtains on
curtain-sided trailers can improve fuel economy by up to 2.5 percent and 4.5 percent, respectively.
Gap reducers that decrease the trailer gap from 45 to 25 inches can improve fuel economy as much as 2 percent. Ac-
cording to the manufacturers, the addition of trailer side skirts can also improve fuel economy by up to 5 percent.
Single Unit Truck Aerodynamics
Single unit truck aerodynamic options
Streamlined front profile with sloped hood to reduce drag
Rounded air deflector can be added to van-style bodies to reduce drag
When using rounded air deflectors, manufacturers claim fuel savings of up to 5 percent, which reduces annual fuel
use by about 80 gallons and saves over $100 in fuel costs. Single unit trucks with higher annual mileage could real-
ize even larger benefits.
Savings and benefits
An aerodynamic long-haul combination truck can realize a fuel economy increase of 11 percent, as compared to a
typical long-haul combination truck. This would result in about 1,600 gallons saved, reducing fuel costs by over $6,000
and saving 16 metric tons of carbon dioxide. A single unit aerodynamic truck improves fuel economy by 5 percent,
saving 75 gallons and nearly 1 metric ton of carbon dioxide. The initial expense of installing aerodynamic features can
be quickly recouped through fuel savings.
Aerodynamic Trailer Annual Savings
Single Unit Truck Annual Sai/ings
Fuel Economy Increase
New MPG (original MPG of 6)
Fuel Cost Saving
3.6% Fuel Economy Increase
6.2 mpg New MPG (original MPG of 8.54)
Gallons Saved
CO Savings
$2,200 Fuel Cost Saving
8.97 mpg
76 gallons
0.76 metric tons
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SmartWay Transport | EPA^120-FOO-036 | www.epa.gov/smartway | 734-214-4767 | smartway_transport@epa.gov
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