Driving slower really does save gas

If you're a fan of National Public Radio's "Car Talk," you've probably heard Click and Clack proselytize about slowing down to save gas. According to the Tappet Brothers, drivers could lose up to 15 percent in fuel economy for every extra 10 miles per hour they drive.

Two months ago I decided to find out if they were right. Since most of my daily commute involves an interstate highway, calculating how much money I could save was fairly easy.

The first month I drove the speed limit in town and 60 mph on the highway. The second month I drove 75 to 80 mph on the highway, 3 to 5 mph over the speed limit on other roads, and made plenty of jack-rabbit starts and stops.

The difference was stunning, particularly considering that I drive a 1995 Mitsubishi Eclipse.

In the first month, I got 27 miles per gallon, filled my tank twice and spent $70. In the second month, I got a measly 20 mpg, filled my tank three times and spent $105. (The average gas price was $2.52 per gallon.)

That's a savings of $35 per month, $420 per year.

Here are a few other things I learned:

2. Avoid drive times. My workday usually starts at 9 a.m. For most of the first month, I made it to work at 8:30 or 8:45 a.m. and missed an average of five long waits at red lights.

3. Skip the stunts. Don't pay for the thrill of driving like a maniac. According to the EPA, jack-rabbit starts and sudden braking use more gas than driving at top speeds. They also earn you more traffic tickets and don't really save you much time.

4. Turn it off. Men have told me for years that I was wasting more gas by turning off my engine at railroad tracks and the drive-up bank. Turns out they were wrong. Your mpg rating is actually negative when you idle for more than one minute. I've even taken to turning the engine off at super-long stoplights, irritating the men in my life even further.

5. Skip long warm-ups. Modern vehicles have automatic chokes, so you don't need to step on the gas pedal before starting the engine. Most cars only need 30 seconds to warm up. That's roughly the time it takes to stow your stuff and fasten the seat belt. In cold weather, just drive slowly until the engine reaches proper operating temperature.

6. Don't buy the premium myth. Does your owner's manual say "Premium Unleaded Only"? If not, then don't use premium fuel. You just saved about 40 cents a gallon. (If your manual does call for 91 octane, however, you have to use it or hear that irritating pinging sound.) According to the Car Talk Guys, if your engine is designed to run on regular unleaded gas, there's no benefit to putting in a higher octane.