Host:Should I avoid high speeds?
David Rizzo: No one likes to hear that they have to go slower but if you are interested in saving miles per gallon or getting more miles per gallon, yes you have to slow down and it has to do with pushing wind out of the way of the car. If we are driving in a vacuum it would take very little energy to propel our car down the road, but the Coefficient of Drag, the wind resistance on our car is everything and the faster you go that drag raises exponentially. Let me put in perspective, the average ideal driving speed is about 35-50 miles per hour, that's where your car is getting the best gas mileage. If you accelerate from 55-65 and keep it there you are loosing 3 miles per gallon. If you accelerate from 55-70 all of a sudden you are loosing 4.
5 miles per gallon, we are getting serious here. To put it terms of dollars and cents, every 10 miles that you drive above 60 miles per hour cost you an extra 50 cents. In other words it's like paying instead of $4 a gallon you are paying $4.
50 a gallon just for the privilege to go 60-70 miles per hour. So, now if you slow down you are definitely going to put money back in your pocket.