Combining errands into one trip saves you time and money. Several short trips taken from a cold start can use twice as much fuel as a longer multipurpose trip covering the same distance when the engine is warm. Trip planning ensures that traveling is done when the engine is warmed-up and efficient.

With a little planning, you can avoid retracing your route and reduce the distance you travel as well. You'll not only save fuel, but also reduce wear and tear on your car.

Commuting
If you can stagger your work hours to avoid peak rush hours, you'll spend less time sitting in traffic and consume less fuel.

If you own more than one vehicle, drive the one that gets the best gas mileage whenever possible.

Consider telecommuting (working from home) if your employer permits it.

If possible, take advantage of carpools and ride-share programs. You can cut your weekly fuel costs in half and save wear on your car if you take turns driving with other commuters. Many urban areas allow vehicles with multiple passengers to use special High Occupancy Vehicle (HOV) lanes.

Consider using public transit if it is available and convenient for you.

Traveling
A roof rack or carrier provides additional cargo space and may allow you to meet your needs with a smaller car. However, a loaded roof rack can decrease your fuel economy by 5 percent. Reduce aerodynamic drag and improve your fuel economy by placing items inside the trunk whenever possible.

Avoid carrying unneeded items, especially heavy ones. An extra 100 lbs in the trunk reduces a typical car's fuel economy by 1-2 percent.

Source: www.fueleconomy.gov