How Do I Increase Fuel Efficiency in Cars?

Drive efficiently to save fuel -- without rapid stops and starts, and keeping to the speed limit. Driving at lower speeds, especially under 60 mph, saves gas significantly. For every 5 mph you drive in excess of 60 mph, your driving is costing you about an additional quarter per gallon. Less aggressive freeway driving can also improve gas mileage, up to 33 percent. A conservative approach is not only safer, but saves money.

Remove unnecessary items from your car, particularly if they are heavy, because carrying heavy loads increases gas consumption. For each extra 100 pounds of weight, your car's mileage can go down by 2 percent. Packing items on a roof rack or carrier encourages wind resistance and decreases fuel economy by about 5 percent. Try to keep smaller items inside the trunk or car.

Keep idling to a minimum. Not only does it not get you anywhere, but it consumes fuel in the process. Most newer engines do not need to be warmed up. The engine warms up more thoroughly when it is driving. A larger car that is left idling uses more fuel than a smaller car.

Maintain your car in good running condition. Simply keeping the engine tuned can save up to 4 percent of fuel. Inflating tires to their recommended pressure can improve fuel efficiency by 3 percent. Change your oil on schedule. Use the manufacturer's recommended grade of motor oil and select a brand that says "Energy Conserving." This type of oil contains friction-reducing additives that may improve fuel economy.

Limit air conditioner use when driving at lower speeds. An air conditioner that is on dramatically reduces fuel economy, although driving over 45 mph with the windows down creates drag on the car that increases fuel consumption.

Park in a cool area or the shade. Heat causes gasoline to evaporate. Parking in a shady spot has the added benefit of keeping the car cool, lessening the necessity for air conditioning.