From Fivecentnickel.com:

With gas prices on the rise, I thought I’d highlight a recent article from Consumer Reports on ways to save on gas — and ways not to. Given the results of my recent experiment on improving gas mileage, I can vouch for pretty much all of these.

1. Drive at a moderate speed. Keeping a lid on your speed is the #1 thing you can do to improve mileage. In their test car (a Toyota Camry), CR estimated that mileage dropped from 40 mpg to 35 mpg when they increased cruising speed from 55 mph to 65 mph. Speeding up to 75 mph dropped mileage another 5 mpg. While the extent of the drop will vary across makes and models, keeping an eye on the speedometer, especially when driving on the highway, will save gas.

2. Drive smoothly. Avoid rapid acceleration and hard braking. Once up to speed, try to maintain a steady pace. Jackrabbit starts burn excess gas, and unnecessary braking just converts energy gained from burning gas into heat (and it wears out your brakes).

3. Reduce unnecessary drag. Even empty roof racks can reduce mileage. Try to keep your luggage inside your vehicle, and if you’re not using your roof rack, remove it.

4. Don’t use premium fuel if you don’t need to. If your car is designed to run on regular unleaded, putting in premium won’t help. Using premium won’t hurt, but you’ll be spending an extra $0.20 per gallon for no reason.

5. Minimize driving with a cold engine. Engines run most efficiently when warm. Try to group errands together. This not only minimizes back and forth trips, but also maximizes efficiency by not letting the engine cool off too much.a

6. Keep tires properly inflated. Underinflated tires can cause a number of problems, not the least of which is reduced gas mileage.

7. Buy tires with lower rolling resistance. Less friction = less wasted energy, which translates into more miles per gallon. Believe it or not, this can account for a 1-2 mpg difference.

8. Avoid idling for long periods. If you’re burning gas, but not going anywhere, you’re getting zero mpg.

And here are three gas myths that don’t help at all:

1. Morning fill-ups. I’ve heard on more than one occasion that you should buy gas in the morning because it’s cooler, and the gas will be denser. The argument goes that this will result in more gas for your money. Problem is, it’s not true. Gas is stored underground, and the temperature barely changes at all over the course of the day.

2. Air conditioning vs. opening windows. While air conditioning can reduce your mileage, so does opening the windows. But in their tests, CR concluded that both effect were negligible. Note, however, that this testing was done at highway cruising speeds. I suspect that air condition might have a larger effect in stop and go traffic.

3. A dirty air filter. A popular recommendation at oil change places is to replace your air filter since a dirty filter supposedly reduces mileage. That being said, CR’s results indicated that, unlike the case with older cars, the mileage of newer models is unaffected by a dirty filter. The reason for this is that modern engines can compensate for a dirty filter and keep the air/fuel ratio constant.

Gosh’s two cents worth:

About accelerating — the trucker’s adage is accelerate as if there were an egg between your foot and the gas pedal.

Anticipating traffic light changes in light traffic can increase mileage. Brake before you have to and creep up to the light so you are still rolling instead of driving up and then braking to a stop helps a lot.

Don’t press down harder on the gas pedal going up hills, let the speed slow down. If you accelerate to the top, you are just going to use the brakes on the downside anyway. Approaching the hilltop slowly, you can let it ride downhill with minimal braking.

Drive to avoid braking as much as possible to do safely. Braking wastes gas. Take it easy and anticipate. Use rises and hills for braking when needed.