WITH GAS PRICES liable to skyrocket again, here's how to pare down your gas bills-and treat the planet a bit more kindly.

* Drive sensibly: Aggressive driving (speeding, rapid acceleration, and braking) wastes gas. It can lower your gas mileage by 5% around town and 33% at highway speeds.

* Observe the speed limit: Each 5 mph you drive over 60 mph is like paying an additional 6% per gallon.

* Avoid excessive idling.

* Use cruise control or overdrive gears.

* Keep your engine properly tuned: Fixing a car that's noticeably out of tune or that's failed an emissions test can improve its gas mileage by about 4% though results may vary. If your car has a faulty oxygen sensor, having it repaired may improve your gas mileage as much as 40%.

* Check and replace air filters regularly: Replacing a clogged air filter can improve your car's gas mileage by as much as 10%.

* Keep your tires properly inflated: This step can improve your gas mileage by over 3%.

* Use the manufacturer's recommended grade of motor oil: Improve your gas mileage by 1% to 2% by using this oil.

* Combining errands into one trip saves you money-and time.

* Travel smart to and from work: If possible, take advantage of carpools and ride-share programs, or use public transit if you can.

* Travel smart on road trips: Using a loaded roof rack can decrease your fuel economy by 5%. An extra 100 pounds in the trunk reduces a typical car's fuel economy by 1% to 2%.

* Choose a more efficient vehicle.

If you're thinking about buying a new vehicle, visit http://www.fueleconomy. gov to find the most fuel-efficient vehicle that will meet your needs. The difference between a car that gets 20 miles per gallon (MPG) and one that gets 30 MPG amounts to $3,000 over 5 years (based on 15,000 miles per year and gas prices of $3 per gallon).

Source: Adapted from http://www.fueleconomy.gov.