Save up to $1 per gallon for gas

[aztc]

Drive Sensibly

Aggressive driving (speeding, rapid acceleration and braking) wastes gas. It can lower your gas mileage by 33 percent at highway speeds and by 5 percent around town. Sensible driving is also safer for you and others, so you may save more than gas money.

Fuel Economy Benefit: 5-33%
Equivalent Gasoline Savings: $0.15-$1.01/gallon

Observe the Speed Limit

Graph showing MPG VS speed MPG decreases rapidly at speeds above 60 mphWhile each vehicle reaches its optimal fuel economy at a different speed (or range of speeds), gas mileage usually decreases rapidly at speeds above 60 mph.

As a rule of thumb, you can assume that each 5 mph you drive over 60 mph is like paying an additional $0.21 per gallon for gas.

Observing the speed limit is also safer.

Fuel Economy Benefit: 7-23%
Equivalent Gasoline Savings: $0.21-$0.71/gallon


Source:
http://www.fueleconomy.gov/feg/driveHabits.shtml

[thecrow]

1. I have gotten into this thing

I set my cruise control for the speed limit, and when I come to a hill, I just coast down it.
I have noticed that other drivers race for the hilltop and then brake all the way down it.
I save a lot of gas by just coasting.

[Kokonoe]

2. At 0 (mph) you save 100 %.

[Massacure]

3. Or at least once your insurance expires.

:P

[muriel_volestrangler]

4. Can anyone explain why 50mph is more efficient than 30mph?

I understand that an engine may have a speed that gets the best economy - but the transmission gearing should enable us to use that engine speed at lower road speeds. Meanwhile, the air resistance at lower speeds should mean they are more economical, not less. I suppose there is fuel used just to keep the engine turning - and if that costs, say, half a gallon an hour, you get more miles in that hour if you are going at high speed than low speed. But I wouldn't have thought that would make up for the air resistance (and other speed-dependent losses such as in the tyres). So can anyone explain how the Department of Energy produced that graph?

[Oerdin]

5. That curve is BS.

It varies from engine to engine and car to car. True, the faster you go the mone energy you require to go that fast however it is far better to go fast in a light four cylinder car then a heavy V-12 car. It's even better to go in a light turbo charged four cylinder car. That's just the facts though moderating speed will help to a certain extant. I just don't know if it applies to your average driver.

[Kolesar]

6. Performance should be highest after shifting into the highest gear

Any higher speed after that should decrease your fuel economy performance. Drag is a squared function of velocity. That means a forty percent increase in velocity doubles the drag, and drag means work.