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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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