Every vehicle reaches its optimal fuel economy at a different speed, but gas mileage usually decreases quite rapidly at speeds above 60 mph. In fact, you can assume that each 5 mph you drive over 60 mph is like paying an additional $0.24 per gallon for gas! And, let's face it, observing the speed limit is also safer, too!
by TheStig on January 04 2009
this tip works for 82% of voting Fuelly members.