Does going 60 mph on the highway save you 30% more gas than going 70 mph?

Question

someone told me going 60 mph on the highway will save you 30% more gas than going 70 mph. is that true?

Answer 1

Yes. I was driving when the national speed limit was dropped to 55 I saw a large improvement in mpg. I think if gas hits $5 the federal government will again lower the national speed limit.

Answer 2

gas used goes up as the square (at least) of the speed. so doubling the speed used 4x more gas.

60 to 70 is a 17% change, so you should use 34% more gas.

This is all theoretical, and other things can change these numbers, but it's a ballpark.

Answer 3

just know when your car shifts... lower rpm

Answer 4

I know it will save you quite a bit of gas...30% sounds reasonable.

iblackvelvet made a huge miscalculation. 30% is more like going from 15mpg to 19-20mpg, not 45 like you said (that would be 300%!)

You can also accelerate more slowly to save gas...not ridiculously slow, but you don't need to "hot rod", as that would obviously burn more gas.

Answer 5

yes it does save you gas.even going a little slower like 55 mph hour will save you gas. right aroung 55-60 the tranny shifts and kind of lets it rest which means less gas but still the same speed. depening on what king of vehicle you got. they all differ.

Answer 6

No, maybe 10% .  30 % would be like going from 15 mpg. to 45mpg.