Oak Ridge National Laboratory researchers determined that for every 5 miles per hour that drivers travel over a 50-mph speed limit, fuel economy decreases by 7% and equates to paying an extra 28 cents per gallon at current average U.S. fuel prices.
This finding was released in the updated 2022-23 Fuel Economy Guide, which provides tips to save on fuel. Researchers use data from demonstrations to show impacts on fuel efficiency such as speeding, low tire pressure, neglecting vehicle maintenance or carrying a heavy roof rack.
“Simple adjustments can lead to big impacts,” ORNL’s Stacy Davis said. “Make sure you’re driving the most fuel-efficient vehicle and using the recommended octane. The difference for a vehicle that gets 20 miles per gallon and one that gets 30 miles per gallon is about 7 cents per mile. That’s a savings of $70 for a 1,000-mile roundtrip.”
Davis also recommended using the guide’s Trip Calculator to estimate fuel expenditures.