Effect             Conditions        Average Fuel        Maximum Fuel

                                     Economy             Economy

                                     Reduction           Reduction



Temperature*       20F vs 77F          5.3%                13%



Head Wind            20 mph            2.3%                 6%



Hills/Mountains    7% road grade       1.9%                25%



Poor road         Gravel, curves,      4.3%                50%

conditions*       slush, snow, etc.





Traffic           20 vs 27 mph        10.6%                15%

Congestion        average speed



Highway speed     70 vs 55 mph        N/A                  25%



Acceleration      "Hard" vs "Easy"    11.8%                20%

Rate



Wheel                 1/2 inch        <1%                  10%

Alignment



Tire Type           non-radial        <1%                   4%

                    vs radial



Tire Pressure*       15 psi vs         3.3%                 6%

                     26 psi



Air Conditioning    Extreme Heat      21%                  N/A



Defroster*          Extreme Use       Analogous to A/C on some vehicle



Idling/Warmup*       Winter vs        Variable             20%

                      Summer          with Driver



Windows            Open vs Closed     Unknown but likely small

Source:

Webpage: http://www.epa.gov/orcdizux/rfgecon.htm