The safety slogan ”Speed Kills” is due for a 21st century update to “Speed Kills Your Gas Mileage.” It works both ways: Fuel consumption rises when creeping along in stop-and-go traffic and when humming along at 75 mph.
The government’s mileage guide shows that the optimum steady-speed efficiency is from 45 mph to 60 mph. By 75 mph, the drop-off is 7 mpg (from a peak mileage of 30 mpg). The EPA also says that dropping speed from 65 mph to 55 mph improves mileage by 15 percent.
Quick starts and hard braking can diminish mileage by as much as one-third at highway speeds and by 5 percent around town, according to the EPA. Maintain momentum and avoid the brakes to save gas and frustration. Circumvent congestion when possible and drive as if there’s an egg between your foot and the throttle to minimize rapid acceleration.
Using cruise control on the highway may boost fuel economy as well: A recent study by Edmunds.com says that it can improve mileage by as much as 7 percent.
