There are many tips that help increase your car's mpg. Hypermiling has been covered, but includes some extreme driving that turns many people off. I also mentioned a few in a previous article, gas efficient driving, that included things like removing items from your trunk, inflating your tires, and keeping your engine in good condition with regular maintenance. But out of all the suggestions, there was only one thing that skyrocketed the mileage on my 2001 Civic from 32 to 47 mpg.

All I did was slow down.

I know that's a tall order for our fast-foward-instant-gratification lifestyle. But imagine getting an extra 15 miles per gallon (that's at least an extra 200 miles per tank). With current gas prices and our slowing economy, it just might be worth taking it easy on the gas pedal.

What exactly do I mean by slowing down? First, let's talk about highway speeds.

In a typical family sedan, every 10 miles per hour you drive over 60 is like the price of gasoline going up about 54 cents a gallon. That figure will be even higher for less fuel-efficient vehicles that go fewer miles on a gallon to start with. - CNNMoney.com

That is based on a $3.25 price per gallon.

In response to the oil crisis in 1973, a 55 mph national speed limit was imposed. 55 mph is still a car's "sweet spot" for fuel efficiency. What uses the most energy of a car at high speeds is the force of air. The increase in wind resistance is exponential, which means it rises more steeply between 70 and 80 mph than 50 to 60. That's why the mpg graph looks like this (from fueleconomy.gov).

I know we're all busy and we've all got places to go. But stop and consider just how much time you're saving by driving faster. If you need to go 30 miles, driving at 60 mph will get you there in 30 minutes. Whereas driving 75 mph will get you there a whole six minutes earlier. On top of that, you used up way more gas for going the same distance!

Increasing your highway cruising speed from 55mph (90km/h) to 75mph (120km/h) can raise fuel consumption as much as 20%. - eartheasy.com

What is six minutes worth to you?

In addition to slowing down on the highway, you can raise your mpg on city streets by doing the same thing. I don't mean driving 10-20 mph, but anticipating stops by taking your foot off the gas pedal to slow down. What uses the most gas when driving on city streets is accelerating. By coasting (taking your foot off the gas and letting your car's momentum move it forward) to a stoplight instead of driving right up to it and then slamming on the brakes does two things.

First, the light may turn green by the time you get there, so you would be accelerating from a coast than from a full stop. Second, you've already used up gas by accelerating to your current speed. If you coast to a stop, the gas the engine already ate up got you further than if you continue to make your engine burn gas just to have that momentum cut short by braking. Going further with less gas is the essence of fuel economy.

It takes a bit of getting used to, because everyone else seems to be zooming by. But if you pay attention, you'll realize that the guy who stepped on the gas just to get around you ended up stopped at the red light that you coasted up to. And if you're usually the guy who weaves in and out of lanes to get past slow cars, you probably never noticed those same cars were still right behind you a few miles later.

Increasing your mpg not only saves money on gas, it lowers our country's demand on oil. If you don't want to give up your SUV, at least make it go further on less gas. So give it shot. You've only got a few minutes to lose.