How to save on gas

Cost-conscious motorists can make their gas last longer by slowing down, being patient and not idling.

These are some of the tips from the U.S. Department of Energy's office of energy efficiency and renewable energy. The agency has compiled some gas-saving measures at www.fueleconomy.gov.

Here's what agency officials and other experts advise on maximizing your vehicle's gasoline.

Drive smart: Rapid acceleration and braking is one of the quickest ways to waste gas. Aggressive drivers would save between 5 and 33 percent of their fuel if they were more patient, federal energy officials estimate.

Follow speed limits: The optimum speed of cars varies from vehicle to vehicle depending on its shape and engine. But generally the average car is most fuel-efficient at about 55 mph, studies have shown. That's because most vehicles' wind resistance and engine performance top out around there. Cars with more powerful engines may actually perform better at high speeds, while small vehicles can exceed 60 miles per gallon at about 30 mph.

Lighten the load: Whatever doesn't need to be in the car when it's in operation should be taken out. Federal officials estimate an extra 100 pounds could reduce fuel efficiency by 2 percent.

Turn it off: Idling for long periods of time is one of the greatest gas wasters. Cars with larger engines waste more gas idling than small-engine cars do. Motorists should consider turning off their cars when they know they know they won't be moving for a while.

Cruising along: Motorists should use cruise control on the highway because it maintains a steady speed. Federal energy officials said studies have shown cars using cruise control often get better gas mileage than those that don't.