Fuel economy tests show that, in city driving, a conventional gasoline car’s gas mileage is roughly 15% lower at 20°F than it would be at 77°F. It can drop as much as 24% for short (3- to 4-mile) trips.You can improve your gas mileage by 0.6% on average—up to 3% in some cases—by keeping your tires inflated to the proper pressure. Under-inflated tires can lower gas mileage by about 0.2% for every 1 psi drop in the average pressure of all tires. Properly inflated tires are safer and last longer.The proper tire pressure for your vehicle is usually found on a sticker in the driver’s side door jamb or the glove box and in your owner’s manual—according to the federal Office of Energy Efficiency and Renewable Energy. Do not use the pressure printed on the tire’s sidewall which is the maximum, not recommended for daily use. See more efficiency tips at www.fueleconomy.gov