Improved Aerodynamics: A Glance at Clean Freight Strategies

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U.S. Environmental Protection Agency +
Improved Aerodynamics
A Glance at Clean Freight Strategies
ENERGY & FUEL SAVINGS
Aerodynamic Long Haul
Combination Truck
Using a streamLined-profiLe tractor with aerodynamic devices can improve fuel
economy by over 3 percent and will reduce fuel costs by over $1,500. When adding
an aerodynamic trailer, you can get up to an 11 percent increase in fuel economy,
saving 16 metric tons of carbon dioxide.
Gallons saved:
WHAT IS THE CHALLENGE?
1,650
gallons
CO2 savings:
16.8
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 significant 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.

metric tons
WHAT IS THE SOLUTION?
A number of options exist to improve aerodynamics and improve fuel efficiency.
Fuel Economy
Increase:
Tractor Aerodynamics
Truck tractor aerodynamic options:
11%
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
MPG (originaL 6 mpg):
6.6
mpg
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
tractor 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.
Fuel Cost Savings:
$4,810
Trailer Aerodynamics
Truck trailer aerodynamic options:
Gap Reducer (these devices affix to the front of the trailer to minimize the gap
between the tractor and trailer, minimizing air turbulence in turn)
EPA-420-F-19-022 | August 2019 | SmartWay Transport Partnership | epa.gov/smartway
(continued)

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Improved Aerodynamics:
A Glance at Clean Freight Strategies (continued)
ENERGY & FUEL SAVINGS
Aerodynamic Tractor
Annual Savings
Fuel Economy Increase:
3.6%
MPG (original. 6 mpg):
6.2
mpg
Fuel Cost Savings:
$1,690
Single Unit Truck
Annual Savings
Gallons saved:
75
C02 savings:
0.8
metric tons
Fuel Economy Increase:
5%
MPG (original. 8.54 mpg):
8.97
mpg
Fuel Cost Savings:
$285
Please visit the SmartWay website at www.epa.gov/smartway
to access more tech bulletins.
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 (reduces drag by arranging cargo as low as possible
and at uniform height)
Wheelbase and fifth-wheel settings (positioning the trailer as close to the rear of
the tractor as possible to 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. According 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 $300 in fuel costs.
Single unit trucks with higher annual mileage could realize 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 $4,800 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.
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Trucking firms can specify aerodynamic options when purchasing
a new truck and consider adding aerodynamic devices to existing
trucks and trailers. Some aerodynamic options are standard on
many trucks, like a streamlined hood. Others can be purchased
and installed for an additional cost.
For more information on aerodynamic devices, contact your local
truck dealer, truck equipment vendor, or trucking association.

SmartWay
U.S. Environmental Protection Agency^

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