Now we get to the "fun stuff". Some of the best gas mileage improvements revolve around the way we drive - driving for improved mpg, the 'heart' of hypermiling.
Idling. Just say no!
You get exactly zero miles per gallon when you are idling. And as long as your car is running, your cost per mile for gas goes up to infinity. Now of course it takes more gas to start your car than to idle - to a point. If you are going to be stopped for more than 30 seconds, you will save by shutting your car off.
Theoretically, if the engine is on, you want to be moving. If you aren't moving, you want your engine to be off. Obviously it isn't practical to do this 100%, but it helps to think in these terms.
NOTE: In some areas, and on many roads, it is illegal to turn off your engine while driving. Also, on many cars, turning the engine off disables the brakes. This can be extremely dangerous unless you are at a stop.
Drive slower. Particularly at highway speeds, most engines become extremely inefficient at higher speeds. In fact, the old national 55 mile per hour speed limit was imposed as a result of the 1970’s gas embargo, as a way to reduce fuel consumption.
Combine trips. It doesn’t take a rocket scientist to realize that driving to the store and back, then to the dry cleaners and back will probably use more gasoline than driving to the store, then the dry cleaners, then home.
Braking – There's more (or less!) to it than you think!
Unless you are driving a Hybrid, braking reduces your overall gas mileage. In most cases, you will use less gas by driving slower and braking less, even though it takes longer to get there.
One of the key techniques in hypermiling is to reduce braking. Braking can be reduced significantly by "thinking ahead".
The moment you see brake lights light up in front of you, you should immediately take your foot off of the accelerator.
You can also try to "time" traffic lights. Many main streets and avenues have their traffic lights synchronized, usually timed to the speed limit. This means that if you are moving at the right speed, you will always have a green light in front of you.
If the lights are timed, this can save a great deal of accelerating and braking.
Use your momentum whenever possible. You've already "paid" for that forward movement. Once you see brake lights, you can usually stop accelerating and coast to a stop.
If you aren't going too fast, it's possible to take turns without braking. NOTE: DO NOT TRY TO TAKE TURNS WITHOUT BRAKING IF YOU ARE GOING TOO FAST TO DO SO SAFELY!
Using neutral to save gas.
NOTE: Shifting into neutral means you can't accelerate to get 'out of the way' – DO NOT shift into neutral when you may need to move out of the way.
Your engine's RPM slows to idling speed when you are in neutral. It also disengages the gears, putting less load on the engine, which then requires less gas.
You can often shift into neutral when you are approaching a stop.
Coasting while in neutral can be done if you are already moving with some speed, especially if you are on a slope or down-grade.
"Drafting" - this is the most controversial hypermiling technique. Drafting is when you get behind a larger vehicle, allowing them to break the air resistance in front of you.
A large vehicle moving fast also creates a 'funneling' effect, in effect 'pulling' whatever is directly behind it forward. Drafting is what NASCAR drivers do when they tailgate each other at high speed.
DO NOT ATTEMPT DRAFTING – IT IS EXTREMELY DANGEROUS!
Without drafting, you can still benefit by driving behind a large vehicle at an appropriately safe distance.
Driving slowly is another key hypermiling technique. Particularly at highway speeds, your engine runs less efficiently the faster you drive.
Staying within the speed limit actually saves quite a bit of gas. In fact, the US national speed limit was originally imposed in response to the oil embargo of the 1970's.
