Planning & Combining Trips

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, and it can reduce the distance you travel.
Commuting
Stagger your work hours to avoid
peak rush hours.
Drive your most fuel-efficient vehicle.
Consider telecommuting (working from home) if your employer permits it.
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 High Occupancy Vehicle (HOV) lanes which are typically less congested, further improving your fuel economy.
Consider using public transit if it is available and convenient for you. The American Public Transit Transportation Association has links to information about public transportation in your state.
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.