Exceeding 40 mph forces your auto to overcome tremendous wind resistance.

Never exceed legal speed limit. Primarily they are set for your traveling safety, however better gas efficiency also occurs. Traveling at 55 mph give you up to 21% better mileage when compared to former legal speed limits of 65 mph and 70 mph.

Traveling at fast rates in low gears can consume up to 45% more fuel than is needed.

Manual shift driven cars allow you to change to highest gear as soon as possible, thereby letting you save gas if you "nurse it along". However, if you cause the engine to "bog down", premature wearing of engine parts occurs.

Keep windows closed when traveling at highway speeds. Open windows cause air drag, reducing your mileage by 10%.

Drive steadily. Slowing down or speeding up wastes fuel. Also avoid tailgating - the driver in front of you is unpredictable. Not only is it unsafe, but if affects your economy, if he slows down unexpectedly.