-Fuel economy may not be top of mind when you're carting kids from birthday parties to soccer practice. But with the average U.S. households spending nearly 3,000 a year at the pump, it pays to get the most miles per gallon. Here are three ways to save. First, make sure your tires are aligned and properly inflated. Less work for your engine means less gas. Low rolling resistance tires can further improve gas mileage. Second, lighten up. A cluttered car means extra weight and lower gas mileage. For every 100 pounds you haul, your fuel economy drops by 1 to 2 percent. If you're packing for a road trip, place the bags inside the vehicle instead of strapping them to the roof, which creates additional drag. Finally, don't run your vehicle idle. If you're parked for more than a minute or two, turn the engine off and restart it when you're ready to roll. A few simple steps can help reduce the number of times you fill up your car. The environment and your wallet will thank you.