Change Driving Habits to Save Gas
As far back as the seventies, drivers were growing more concerned about getting the most miles per gallon from their vehicles. The more observant of them noticed that modifying their driving habits had an effect on fuel economy. Vacuum gauges were available on some models to give drivers a crude indication of fuel economy in various driving situations. Sampling air pressure in the intake manifold, the gauge would signal when the driver was using excessive throttle and wasting gas. The driver could then modify his driving habits to save gas. This was a primitive manifestation of a practice some drivers use today called "hypermiling."

Fuel Economy in Today's Vehicles
The EPA is responsible for estimating the fuel economy of vehicles under a standard set driving conditions. In 2008, the EPA changed the spectrum of normal driving conditions to more accurately reflect reality, by including aggressive driving, accelerating, and the use of air conditioning. The EPA estimates always come with the disclaimer "Your mileage may vary." This means that, although the rated fuel economy of the 2008 Honda Accord Sedan is 21 mpg city, 31 mpg highway, you will probably not attain this level with your driving habits.

The Essence of Hypermiling
Some drivers have been able to modify their driving habits to exceed the EPA estimates and go where no man has gone before in terms of squeezing every possible mile out of a gallon of gas. Many have become so talented at driving with minimal use of fuel that they have gotten 100 miles per gallon out of their vehicles and more. Through trial and error, hypermilers have learned certain extreme driving techniques that will drastically lower fuel consumption.

Some driving behaviors in the hypermiler's bag of tricks:

• Anticipating upcoming red lights and coasting up to them rather than racing up and applying brakes. The less you need to apply the brakes, the less fuel you waste.
• Allowing a large space between yourself and the next vehicle ahead, to minimize braking in "stop-and-go traffic." As traffic slows, you need to apply the brakes less if you give yourself plenty of room ahead to coast. Note what many 18-wheelers and other heavy trucks do in stop and go traffic: they leave a large space in from of them and slowly decrease speed, trying not to come to a complete stop. They do this to save fuel and wear on the moving parts of the vehicle. Fuel consumption is greatest when you accelerate. Also, it takes more fuel to start moving from a complete stop than it does to increase speed when you are already in motion.
• Avoiding going above the posted speed limit. Fuel consumption is proportional to your speed due to wind resistance and friction.
• Accelerating very slowly from a complete stop. Tests have shown that doing that can increase your gas mileage by 25-35%.
• Maintaining a constant highway speed by using the cruise control. Using cruise control can improve your fuel economy by 5-15%.
• Calculate your gas mileage after each fill-up. The more conscious you are of your gas mileage, the more aware you will be of fuel wasting habits.

Extreme Hypermiling
Those hypermilers who squeeze 150-200 miles out of a gallon of gas in a combustion engine vehicle go to some pretty drastic and even dangerous extremes. While most of us can see the benefits of keeping at or slightly above the speed limit, hypermilers go far slower, giving a generous amount of space between themselves and the driver in front, often upsetting following drivers. Hypermilers find situations on the road when turning off their engines can save fuel, even though this is an illegal and dangerous maneuver. Drafting large trucks is another favorite hypermiler trick by which the hypermiler drives up close behind a big-rig to be pulled along in the truck's "low pressure zone." Make sure you wear your seatbelts when riding with a hypermiler, he probably will not slow down to take a corner.

Rewards of Sane Hypermiling
You can employ some of the safer techniques, and more conservative degrees of hypermiling and reap significant mileage rewards without annoying your fellow drivers to the point of inciting road rage. Without much effort, you can realize a 30-40% improvement in fuel economy just by paying attention to your driving. Another payoff is in money you can save on car repairs, traffic tickets, car accidents, and auto insurance. Hypermiling was created to prove a point about driving habits, the gas crisis, and estimating gas mileage, but it can be of even greater benefit by helping to decrease pollution and stress on the road.