Chart showing that in general fuel economy decreases as speed increases over 50 mph

While each vehicle reaches its optimal fuel economy at a different speed (or range of speeds), gas mileage usually begins to decrease at speeds above 50 mph.


Clean Cities Top 20 Facts

Small changes can make a big impact

Over the last 20 years, Clean Cities coalitions have worked with their stakeholders to reduce petroleum consumption by 5 billion gallons. This has been possible not only by deploying alternative fuels and vehicles, but also through fuel economy improvements, such as using more efficient vehicles (including hybrid electric vehicles [HEVs]) and better driving habits.

In 2012 alone, Clean Cities coalitions reported petroleum savings in these categories of 53 million gallons. This savings equates to preventing 656,000 tons of carbon dioxide from being emitted into the atmosphere, or removing more than 144,000 cars from U.S. roads.

Efficient Vehicles: estimates that you could save about $900 per year on fuel by choosing a vehicle that gets 30 mpg instead of 20 mpg (assuming 15,000 miles of driving annually and a fuel cost of $3.61/gal). Many fleets are turning to HEVs as a strategy to save on fuel costs and reduce emissions. With the exception of plug-in electric vehicles, the top ten most fuel efficient vehicles for model year 2013 are all HEVs.

Driving Habits: Just reducing driving speed can result in significant fuel and cost savings because fuel economy drops significantly at speeds above 50 mph. In fact, each 5 mph you drive over 50 mph is like paying an additional $0.25 per gallon for gas. National Clean Fleets Partner Staples worked with Massachusetts Clean Cities to implement fuel economy improvements in the Staples fleet, including limiting the maximum speed of its delivery trucks to 60 mph. This and other measures allowed Staples to realize a 30% fuel-economy improvement.*

Want to know other ways to go further on a tank of gas? Visit’s Gas Mileage Tips. Also, check out common misconceptions about fuel economy on’s Top Ten list (click the “Misconceptions” tab).

* Clean Cities NowPDF, April 2011, p. 9

Clean Cities 20th Anniversary Logo
  • National Renewable Energy Laboratory
  • For more information:
  • Clean Cities Technical Response Service Team
  • 800-254-6735