What are some tips for economical driving?
I can consistently beat EPA ratings by 10-20%. I can exceed EPA ratings while driving in a comparatively aggressive manner by simply conserving momentum, even while enjoying occaisonal trips to my car's 8300 RPM redline. If you can never match EPA ratings, there are probably a lot of things you can do to improve things. Most people that can never reach them usually have serious technique issues.
Some simple tips:
- Accelerating uses fuel. Don't accelerate too much or too quickly.
This is more involved that it appears at first. The obvious thing is to not accelerate to a speed that would cause you to overshoot the person in front of you. Always accelerate slower than the person in front of you, so that when they slow down, you don't need to slow down yourself. Faster speeds are generally less efficient, so any time you push your speed to a less efficient one, you're wasting fuel.
- Avoid braking as much as possible
Sounds fishy, but there's one thing behind this; if you brake, you are wasting your momentum. If you brake because the car in front of you is going slower than you, see tip 1. High fuel economy is all about using your momentum.
- Keep long following distances
Yes, there is no technique that will increase fuel economy more than drafting (except turning the engine off), but drafting is dangerous as it involves tailgating. The next best thing is staying far off from the next person - this gives you a lot more time to make adjustments in speed - MUCH more gradually, so you're using the brakes less often and also not accelerating too much.
Short shift; shift at a lower RPM than usual. This varies by car; in my Civic Si, 3,000 RPMs is a pretty low shift point, but in a car with more torque, you can probably get away with shifting closer to 2,000 RPMs. Also, skip gears around town, and it's better to apply more throttle in a higher gear than less throttle in a lower gear. Half throttle in top gear when you're going 40mph is not going to kill your fuel economy with a manual.
Many cars have an "eco" mode. Use it. This will shift earlier, stay in higher gears, and downshift more slowly than normal. If you don't have an eco mode, that's fine. It helps to be aware of how much throttle will cause the transmission to downshift - and don't let that happen.
- Be smooth with the pedals
Both gas and brake. If you stomp on the gas, you'll accelerate quicker, and also be more likely to overshoot your target speed. Same thing with brakes - if you have enough following distance, if the person in front of you slows down, you may be able to get away with coasting or very gently, which means you've wasted less energy.
I have been a passenger in many cars where the driver constantly pulses the gas to maintain speed. Pulse, coast, pulse, coast. Even seen it so bad that they cause their car to constantly down and upshift. This is not good! You want to maintain a speed, and it's much better to keep a gentle foot on the pedal than to constantly manipulate it.
As the theme is running, paying extra attention to traffic lights can save you unnecessary braking and acceleration. If you're approaching a red light, don't accelerate, no matter how slowly you're going. If you stop, then you idle, then it turns green and you accelerate, think of how much more wasted momentum you've got. If you just coast slowly towards a red light, you're not wasting gas accelerating once, and a second time if it turns green before you get there.
Think race car driver. Seriously. But race car drivers don't drive in a harsh manner. They use smooth, controlled inputs. Don't jerk the car in to turns. Gradually ease the car in to the corner. Use a little bit of the lane, too. Start sharp corners on the outside of the lane, turn in to the apex, smoothly, and complete the corner at the outside of the lane. Like drafting, there is an element of danger to doing this too much, but there's one thing in mind here; maintaining your speed through the corner, so you have to accelerate less going out of it. Differently than a race car driver, you don't want to go in to the corner as quickly as possible - but you do want to slow down the least amount possible so you waste the least amount of momentum. And a more race-like line through a corner increases the turning radius, so you can go faster, and more smoothly through the corner, and exit it at a higher speed.
Also, going through corners in a harsh manner will scrub off more speed than going through them in a very gentle manner - again, that is bad for economy.
When possible, if you're in a hilly area, don't accelerate uphill. It's a waste. In fact, let your speed drop a bit going uphill. If your speed is dropping quickly, you need to give it more throttle; you don't need or want to climb hills on 55mph highways at 30mph. But don't freak out of you're doing 48-50 at the top. On long climbs, simply maintain a modest speed that does not disrupt the flow of traffic.
Likewise, coast down the hill. Don't brake unless you're going too fast. If your car is accelerating downhill and you're travelling at a reasonable speed, you should not be pressing the throttle at all.
Maintaining big following distances is a big part of using terrain. If you're on someone's ass, you'll often have to brake downhill because you'll be going faster than them. This is inefficient.
With a manual, shifting to neutral will reduce engine braking. Note that this is illegal in many localities.
If you have a hard time maintaining steady throttle pressure, cruise is probably your best bet. Cruise control is great for very flat areas, but poor in hilly areas as it works inefficiently, prioritizing maintaining speed over optimizing for economy. With some practice, it is very easy to exceed the mileage you get from using cruise control (which will usually exceed EPA at posted speed limits)
Other answers here talk about car maintenance and the like. All is good advice!