U.S. Department of Energy - Energy Efficiency and Renewable Energy
Vehicle Technologies Program
Fact #4: September 23, 1996
Fuel Economy Declines at Higher Speeds
Regardless of their vintage, light-duty vehicles have lower miles per gallon (mpg) values as they travel at higher speeds. In going from 55 mph to 65 mph, early 1970s model year vehicles experience a 12.4% mpg loss, early 1980s model year vehicles experience a 17.8% mpg loss, and mid-1990s model year vehicles experience an 11.3% mpg loss. If speed increases from 65 mph to 70 mph, the additional losses in mpg from these vintages are 8.0%, 9.6%, and 9.6% respectively.
Supporting Information
Fuel Economy Declines at Higher Speeds
| Vintage of Vehicles |
MPG Loss at
55 to 65 mph |
Additional Loss at
65 to 70 mph |
| 1970s |
12.4% |
8.0% |
| 1980s |
17.8% |
9.6% |
| 1990s |
11.3% |
9.6% |
|
Source: Davis, Stacy C., and David N. McFarlin, U.S. Department of Energy Transportation Data Book: Edition 16, Oak Ridge National Laboratory, ORNL-6898, p. 3-47, July 1996. |
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