The Federal Government’s Environmental

The federal government’s Environmental Protection Agency rates fuel mileage in two parts: city and highway. City driving uses more fuel due to frequent starts and stops. Highway driving produces the best mileage, assuming normal highway speeds. Mileage is measured in miles-per-gallon (MPG). Don’t expect your own mileage results to exactly match the EPA’s figures.

Vehicles with manual transmissions generally produce better mileage than those with automatics. Vehicles with 4-cylinder engines are more efficient than the same models with 6-cylinder or 8-cylinder engines. 4-wheel drive vehicles have poorer fuel economy than 2-wheel drive vehicles, or operating in 2-wheel mode.

All-terrain tires and snow tires have more rolling resistance and use more fuel than highway tires. Brand new cars use more fuel during the break-in period (the first 1000-2000 miles) — because the engine is less efficient during that period.

Other factors that help improve gas mileage are: correct tire air pressure, a properly tuned and maintained engine, using the recommended octane-rated fuel, driving at constant speeds when possible, no excessive idling, avoiding jack-rabbit starts, and avoiding frequent short trips. Some people believe that air conditioner use affects mileage significantly.