Changing your Driving Habits 

Brake the right way

1. A car consumes most gas as it accelerates. It's a simply law of physics (force equals mass times acceleration). A moving car doesn't require much gasoline to keep moving (due to the inherent inertia). In real life this means, in order to improve your mileage you need to keep the ride smooth. Let me give you some examples.
 

About 30% of the drivers I see in somewhat heavy traffic apparently cannot control their speed with the accelerator pad alone. Instead I see those guys speed up and slam on the brakes all the time. Obviously, that makes the guy following too close behind very nervous and he too needs to brake and accelerate constantly. In really heavy (but still moving) traffic about 90% of the cars do this. It is relatively easy to hold a speed in a long line of cars without stepping on the brake. Just keep a little bit more distance and try to practice this. If the traffic moves along, you rarely need to brake, unless everything slows down. If you pay attention to the cars ahead of you (not just the one right in front of your nose, but the other cars ahead of that one), you can anticipate when things will slow down and you can ease off the gas. This means you won't lose all that power to friction (on the brakes) and you can keep your speed without having to accelerate. In heavy traffic this is the most efficient way to save gas and can easily get you 10% - 20% better gas mileage.

 

Hybrid drivers

2. If you own a hybrid powered car, the statement above applies even more to you. Try to avoid fast braking. Hybrid cars have the ability to convert braking power into electric energy and store them in their batteries. However this (induction) will only give yo so much braking power. If you need to decelerate faster, your brakes will engage and energy will be lost.

 

So the next time you are approaching a traffic light, start braking a lot sooner and don't slam on the brakes the last minute. This will significantly improve the efficiency of your hybrid car.

 

By starting to decelerate sooner, I can often avoid coming to a complete stop (regular car), before the traffic light switches to green and the cars in front of me start rolling. This way I can keep some of my inertia and don't have to accelerate as much (<- more gas saved).

 

Turn off your air condition

3. This tip might be somewhat impractical in some areas. I would never dare to switch off the air condition of my car in Arizona in the Summer. However I also know that the compressor for the air conditioner loads the motor of my car more, which will reduce my fuel economy. I try not to use the air conditioner if I don't have to.

 

Park your car in the shade if you can, so you won't have to keep the AC working as hard when you go somewhere.

Roll down the windows just a tiny bit, so the air can circulate through your car while you are parked (might not be a good idea in areas with a high theft rate).

 

Turn off the AC 5 minutes before you reach your destination and don't keep it working until the last second.

Shifting Manual

 

4. A manual transmission is truly fantastic. I can only encourage everyone to try it out. You can pretty much determine if you want a sporty shifting (at higher RPM) or a fuel efficient shifting (at low RPM). No matter how "intelligent" automatic transmissions are, they aren't as smart as you. Due to the way an automatic transmission shifts, there are also higher losses associated with automatic transmissions. Overall a manual transmission can be a lot more fuel efficient.

 

If you have a manual transmission and want to save some gas, you need to shift up early and shift down late. 
 

Most people get taught that they need to shift at a certain RPM, which is, excuse me, complete BS. You need to feel the car and the load condition to figure out when you need to shift. A car that goes uphill needs to pull a lot more and should be driven at a higher RPM (or else it jumps). On the other side, if you are gliding along an empty road, you can drive at extremely low RPM (high gear). Then if you want to accelerate (you need a bit more power), you quickly shift down, get up to speed and shift up again. I always shift by feeling the car and I rarely ever look at the RPM (except for my amusement or out of boredom, or if I really want to race and need to shift before the red line).

 

Shifting Automatic

5. If you have a cruise control and there isn't a whole lot of traffic, you probably should use it (it will keep the speed constant and hence doesn't need to accelerate).

 

6. Use the overdrive gears, as this will generally keep your RPM down and your wallet happy.

 

7. Shift into neutral when you are standing still to reduce transmission strain and cool off the transmission. 

I added some more information on shifting, down in the comments below this post. 

 

Reduce weight

8. Coming back to the force equals mass times acceleration. We already established that one shouldn't accelerate as much. You can also try to reduce the mass of your car by emptying out the trunk and removing heavy items that you don't need (keep your spare tire and car lift, but get rid of the gardening equipment).

 

Turn your car off

9. When you turn on a car, it uses a bit of gas. When the car is idling, it uses a fixed amount of gas over a period of time (especially with the AC on).

 

In most scenarios (depending on the car), the energy balance will be positive if you turn off your car for more then 20 seconds.

 

That means you can save gas if you turn off you car while waiting at long traffic light sequences, railroad crossings or while your better half pulls money from the ATM. Any time you can foresee that you will not be moving for more then 30s or 1minute you should turn off the engine to help your vacation budget.

 

Drive slower

10. Yeah right. Obviously thats not something I am all that fond off being the leadfoot driver I am. Well, it's a proven fact that driving fast will increase the drag (turbulence) and thus increase your fuel consumption, however I simply cannot bring myself to drive below the legal speed limit. It's your choice. There is not that much difference between 60mph and 65mph in terms of fuel consumption. However I grew up in Germany (no speed limits). A car racing along at its maximum speed of 200km/h (depending on the car), would consume about twice as much gas as if it were driven at 160km/h. At the upper end of the power spectrum engines become very inefficient.

 

Drafting

11. Drafting has given me some excellent mileage when I used to commute long distance a long time ago. Obviously, it requires a bit of skill and it's not exactly recommended, since you should pay attention to the road and we all know, most people who read this just don't. However it is probably one of the best "secret" fuel saving tips I can give you.

 

This technique is frequently used by race car drivers to gain speed and truck convoys to save fuel.

 

Every car has a certain amount of drag (or wind resistance). This drag, the rolling resistance of your tires (see below under maintenance) and the friction in your engine are the three main causes of reduced efficiency. A car moving through the air causes the air to split around the car and turbulence behind the car. If you drive your car into another cars slipstream, both cars will save fuel (less turbulence). The following car saves the most gasoline. 
 

Now remember, I am not advocating to tailgate. However, you can try to find a large truck (more turbulence and a longer slipstream tail) and slip in there. Now you can still keep some distance (unlike the NASCAR driver) and still save gas. 

 

However, many people cannot regulate their speed without braking (see above). In this case you are probably better off just keeping your distance and not braking.