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MENTAL PROTECTION AGENCY »
U.S. ENVIRONMENTAL PROTECTION AGENCY
Improved Aerodynamics
A Glance at Clean Freight Strategies
ENERGY &
FUEL SAVINGS
Aerodynamic
Long Haul
Combination Truck
Gallons Saved:
1,651 gallons
CO2 Savings:
16.7 metric tons
Fuel Economy
Increase:
11 %
MPG
(original 6 mpg):
6.6 mpg
Fuel Cost Savings:
$6,276
Using a streamlined-profile tractor with aerodynamic devices can improve fuel
economy by over 3 percent and will reduce fuel costs by over$2,ooo. When adding
an aerodynamic trailer, you can get up to an 11 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 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.
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 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.
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)
• 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,
Continued
U.S. EPA SmartWay | EPA-420-F-16-023 | June 2016 | www.epa.gov/smartway
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SmartWay*
MENTAL PROTECTION AGENCY »
U.S. ENVIRONMENTAL PROTECTION AGENCY
Improved Aerodynamics
A Glance at Clean Freight Strategies continued
ENERGY &
FUEL SAVINGS
Aerodynamic
Trailer Annual
Savings
Fuel Economy
Increase:
3.6%
MPG
(original 6 MPG):
6.2 mpg
Fuel Cost Savings:
$2,200
Single Unit Truck
Annual Savings
Gallons Saved:
76 gallons
CO2 Savings:
0.76 metric tons
Fuel Economy
Increase:
5%
MPG
(original 8.54 MPG):
8.97 mpg
Fuel Cost Savings:
$285
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 1 1 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 1 6 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.
NIEXl SI-PS
1 Trucking firms can
specify aerody-
namic 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 pur-
chased and installed
for an additional
cost.
2For more infor-
mation on aero-
dynamic devices,
contact your local
truck dealer, truck
equipment vendor, or
trucking association.
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