The data.
We all flinch at each uptick of gas prices, right? Well, factor in this rule of thumb: each 5 mph you drive over 60 mph is like paying an additional 20 cents per gallon for gas.
EPA data: Gas Mileage vs. Speed
Model | Speed = 40 MPH | Speed = 50 MPH | Speed = 60 MPH | ||||||
Gas Mileage (mpg) | Gas Mileage (mpg) | Gas Mileage (mpg) | |||||||
Sub-Compact | 35 | 36 | 29 | ||||||
Compact | 28 | 30 | 27 | ||||||
Midsize | 21 | 22 | 20 | ||||||
Van | 15 | 17 | 13 | ||||||
Luxury | 13 | 14 | 12 |
The EPA is apparently quite confident that you wouldn't have any inclination to go as fast as 65, and of course no one ever exceeds the legal limit, so why waste time doing the numbers for 70, 75, or 80 mph?
If the sweet spot for fuel efficiency is in the 50's, as the chart indicate, then as you get into the high 60's and above, the addition of each mph requires more fuel than the last. This is explained in greater detail at howstuffworks' article answering the question, "What speed should I drive to get maximum fuel efficiency?"
Other links on other side topics relating to fuel efficient driving: (in progress)
Which is more efficient, air conditioning or windows down?
References (3)
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Response: fe4433e80a1e65dcfc57fe4433e80a1e -
Response: Hybrid CarsIt can periodically become demanding to extract the valuable gas mileage info from the dreadful. -
Response: Run Your Car on Water


Reader Comments (4)
If Pawlenty won't mandate it the least he could do is lead by asking us to slow down.