1. Properly inflate your tires

Statistically, 23% of cars have at least one tire that's under-inflated by 20% or more. According to the Department of Energy, cars with under-inflated tires lose 1% of their fuel efficiency for every 3 PSI beneath their recommended tire pressure. That means one out of every four cars is wasting 3% of the gas put into it. All total, that little bit of waste accounted for 1.2 billion gallons of gas in 2005.

2. Regularly Change Your Oil and Filters

Clean oil and fresh filters are important in making your car run more smoothly. Regularly maintaining both your oil and filters helps to keep your car running more efficiently by preventing buildup. Buildup, as we all know, forces your car to work harder to achieve the same results, and harder work means more gas used.

3. Drive Calmer

Your car's fuel efficiency suffers most at two distinct points ? rapid acceleration and hard breaking. Rapid acceleration forces your engine to work at higher revolution rate, which takes more gas than a slower, gradual acceleration to speed. Breaking quickly forces your car to rapidly change gears, which also leads to high engine revolutions. By breaking and accelerating at a slower rate, your engine operates in a smoother, steadier fashion which in turn leads to a more fuel efficient driving experience.

4. Avoid Left Turns

When international package shipper, UPS, was looking for ways to reduce the fuel costs for their fleet of delivery trucks, one of the first things they did was remove as many left handed turns from delivery routes as possible. The notion, which sounds simple and foolish, turned out to be a winner. Left hand turns frequently involve a car or truck idling. An idle vehicle is not only burning gas while sitting still, but also must break to stop and accelerate out of the idle position ? all three of which are large fuel economy culprits.

5. Clean Out Your Car

The phrase "lean and mean" evokes images of horses and prize fighters and stands on the belief that by cutting out unnecessary weight, both horses and boxers will be faster and more efficient in their respective fields. The same logic applies to your car. By cleaning out the items accumulating in your back seats and trunk, you can significantly lighten the load you put on your car. The heavier the load, the more work your car has to do, and overworking a car is a surefire means of decreasing fuel economy. Clearing the junk from your trunk can reduce excess weight and make your car leaner and meaner.

Taken by themselves, each of these measures can result in a fuel efficiency increase of a few percent. But, when these relatively simple measures are combined, drivers can find their cars with an increased fuel efficiency of 25% or more. With a percentage that large, the savings is rather obvious.