How the EPA Tests Fuel-saving Devices

Fuel Economy and You

We all want to save on gas, but it's not always clear what that really means. After all, you can save on gas by walking everywhere, but most people don't want to do that. For most people, saving gas means they want to use less gas while doing the same amount of driving. In other words, they want to improve their fuel economy.

Fuel economy is the distance a car can travel using one gallon of fuel. That's why it's measured in miles per gallon. A car that's rated at 30 miles to the gallon can travel 30 miles on a single gallon of gasoline. Simple, right? You can find out what kind of fuel economy a car gets by visiting

Where fuel economy gets complicated is when someone buys a car with poor fuel economy and then gets stung by the high price of keeping that car rolling down the road. That's when you usually start looking for ways to improve fuel economy. The good news is that there are some ways you can do it. The Environmental Protection Agency (EPA) says that 74- to 86-percent of the energy that's stored in the gasoline in your tank is lost to other factors. So that means only 14- to 26-percent of the energy in a gallon of gas is actually powering the wheels [source:]. If you can lessen the impact of things like wind and rolling resistance, you can use more of the energy in the gasoline to power the car, and get more miles per gallon. You can also make sure to keep your car in good mechanical shape; well-maintained cars use less gas to go the same distance as an abused clunker. You can also alter your driving habits; hard acceleration uses more fuel than gentle acceleration. And then there's using gadgets or fuel additives that say they can improve your fuel economy.