Green Transport Partnership
\     A  Glance  at  Clean  Freight  Strategies:
       Automatic  Tire
ATls reduce tire
wear, save fuel,
and  reduce
emissions of
greenhouse
gases and  other
pollutants. They
typically pay for
themselves in
under two
years.
       Inflation  Systems
                  What  is the challenge?
                  When not properly inflated, tires wear out faster and increase fuel consumption. Tire
                  makers estimate that 30 percent of all truck trailer tires are underinflated. This can be
                  caused by slow leaks and changes in temperature. Low tire pressure is most common on
                  truck trailers, which may not be maintained as well as truck tractors.
                  Tests by tire makers show that
                  lowering truck tire pressure by
                  14.5 pounds per square inch (psi)
                  from the recommended pressure
                  can result in a five to 10-percent
                  increase in tire rolling resistance,
                  causing a one to two-percent
                  increase in fuel consumption.
                  Underinflated tires wear faster,
                  leading to higher tire costs for fleet
                  owners. An industry "rule of thumb" states that every 10 percent of underinflation causes
                  a 10-percent increase in tire wear. Underinflated tires also cause more frequent blow-outs
                  and punctures, requiring costly road service.
Constant pressure to truck
tires means:

   annual tire maintenance savings of
   at least $280
   annual fuel savings of $140 or more
   fewer roadside emergencies
                  What  is the solution?
                  Automatic tire inflation (ATI) systems monitor and continually adjust the level of pressurized
                  air to tires, maintaining proper tire pressure automatically. No action is required by the driver.
                  One type of system uses the vehicle's existing air-brake compressor to supply all of the tires
                  from a central source. Another type of ATI system uses self-contained compressors mounted
                  on each hub that are powered by the rolling motion of the wheels. Both systems keep tires
                  properly inflated even while moving.
                   The  results are in.
                  ATI systems typically extend tire life by 10 percent. ATls also eliminate the need to check
                  tire pressure manually, saving time for the driver or maintenance staff. Installing an ATI
                  system on the truck drive axles and trailer costs about $800 but saves a total of $280 per
                  year in maintenance costs. For a typical long-haul combination truck, reduced fuel
                  consumption results in additional savings of $145 per year. In total, these savings pay for
                  the initial cost of ATI systems within two years.
                  Next Steps
                  Several manufacturers currently produce ATls for the U.S. The devices are used extensively on
                  logging trucks to allow drivers to easily lower tire pressure when moving from a paved surface
                  to a dirt road. ATls can be installed easily on existing trucks and trailers. Check with your truck
                  dealer about these devices or contact the American Trucking Associations at www.trucking.org.
      Office of Transportation and Air Quality  Mailcode?  October 2002  EPA 420-F-02-027

-------