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How To Conserve Gas While Driving

Gas is too freaking expensive and everyone has their tips for saving gas, though none of it seems to be substantiated by numbers. Well we’re going to peg numbers to these “gas saving techniques” and convert it to dollars so you know how much more per tank you’re paying. We won’t be able to prove our percentage wasted/gained numbers but then again no one can either unless you want to wade through a lot of calculations about coefficient of drag and other terms. We will, however, calculate gas at the rate of $1.93 which is the average retail price of all three grades as of 2/22/05.

Quantifiable Tips:

  1. Don’t Drive Fast: The faster you drive, the greater your aerodynamic drag and thus the greater your gas consumption. The optimal speed appears to be somewhere around 65 mph and the general belief is every ten mph increase will probably reduce your consumption by around 10-15%, or 19-29 cents.
  2. Close Your Windows: This is aerodynamic drag again, expect to save around 10% on the highway, or 19 cents.
  3. Use Air Conditioning Sparingly: This puts more load on the engine, which makes it use about 20% more fuel, or 39 cents.
  4. Properly Inflate Tires: Round tires roll more easily than square tires so make sure they’re inflated to spec. They say a single tire under inflated by 2 PSI result in increased fuel consumption by 1%, or 2 cents. (Plus it leads to uneven wear and more frequent replacement of that tire, which is going to be expensive)
  5. Even Acceleration: Easy there tomcat, don’t gun it because it uses more gas, as much as 20% more or a psychologically maddening 39 cents. If you’re in a hurry, just set back your watch and you’ll be there before you left.
  6. Fill Up Right: Unless your car manual says use higher octane fuel, don’t. You won’t get any benefit from using the more expensive juice, it’s just a waste of money.
  7. Windows or AC Breakeven Point: The widely held breakeven point for whether you should turn on your AC or roll down your windows is 45 m.p.h. While this will vary between vehicles, the belief is at 45 degrees the additional gas needed to fight against wind resistance equals the amount of gas expended by operating the air conditioning system. I believe they did this on an episode of Mythbusters but I can’t find it. (added 9/1/05)

Not-So-Quantifiable Tips:

  1. Lighten Your Load: Empty the trunk and lose some weight, the more you carry the more fuel it’ll use. Lose some weight too.
  2. Service Your Car: Your fuel economy will drop if you have dirty air filters, old oil, old spark plugs, old belts, or other low fluid levels. Keep it in tip top shape and save on your gas and maintenance bills.
  3. Drafting: If you are on the highway and you have the guts to do so, get up close behind a truck and draft. NASCAR guys do it so you should too, just remember to brake whenever the truck does. 🙂 Actually, this is a dangerous practiceas some have noted, but if you actually do wish to draft, you can do it safely by being several car lengths behind a large truck/semi.
  4. Limit Braking: When you brake, you often will need to hit the gas again to get going. Try to look ahead and brake intelligently to reduce how much you need to accelerate.
  5. Tighten The Gas Cap: Gasoline will evaporate, if you don’t seal up that gas tank it will leak out. The Car Care Council estimates that 147 million gallons of gas a year will be lost to evaporation… that’s absolutely ridiculous and dumb as balls.

Use some or all of these tips and save what you can, gas prices are insane these days and will probably only go up. Or swap your car for one of those hybrids or purely electrical cars and get the tax break along with the fuel breaks.