We talked last week about how unnecessary speeding can eat up more gasoline from your tank.

Our friends at www.fueleconomy.gov have released a study suggesting that a such a small percentage of the gas we put in our tanks actually goes to driving, it’s a wonder we’re not all running on fumes trying to rush from place to place.

The study said only 15 percent of a full gas tank is used by the vehicle to actually get from place to place. Where’s the other 85 percent? The answers may surprise you...

• Engine losses — chemical energy that cannot be converted to mechanical energy, lost due to engine friction and wasted heat: 62.4 percent

• Idling Losses — sitting in city traffic: 17.2 percent

• Accessories — running the air conditioning, power steering or radio: 2.2 percent

• Driveline Losses — energy that is lost in your transmission: 5.6 percent

• Aerodynamic Drag — energy used to push air out of the way so the vehicle can slow down or speed up: 2.6 percent

• Rolling Resistance — the measure of force used to move your tires forward in proportion to the weight on the tire: 4.2 percent

• Overcoming Inertia and Braking Losses: energy used to physically move your vehicle forward: 5.8 percent