Scary economy, real solutions

Solution: Drive slower

With gas prices rising, gas-saving advice abounds: Drive more gently, don't carry extra stuff in your trunk, combine your shopping trips.This is all sound advice but there's one driving tip that will probably save you more gas than all the others, especially if you spend a lot of time on the highway: Slow down.

In a typical family sedan, every 10 miles per hour you drive over 60 is like the price of gasoline going up about 54 cents a gallon. That figure will be even higher for less fuel-efficient vehicles that go fewer miles on a gallon to start with.

Every 10 mph faster reduces fuel economy by about 4 mpg, a figure that remains fairly constant regardless of vehicle size, according to Roger Clark, a fuel economy engineer for General Motors. (It might seem that a larger vehicle, with more aerodynamic drag, would see more of an impact. But larger vehicles also tend to have larger, more powerful engines that can more easily cope with the added load.)

That's where that 54 cents a gallon estimate comes from. If a car gets 28 mpg at 65 mph, driving it at 75 would drop that to 24 mpg. Fuel costs over 100 miles, for example - estimated at $3.25 a gallon - would increase by $1.93, or the cost of an additional 0.6 gallons of gas. That would be like paying 54 cents a gallon more for each of the 3.6 gallons used at 65 mph. That per-gallon price difference remains constant over any distance. --Peter Valdes-Dapena

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