Guzzle less gas

The price of oil came down a wee bit last week, but gas prices remain astronomical. Which means that cutting your fuel consumption is not only good for the planet (cars are the source of almost 25 percent of all US carbon emissions, and every gallon of gas burned emits 20 pounds of carbon into the atmosphere) but also immediately, noticeably good for your wallet. Here are some simple ways to guzzle less gas, courtesy of the Environmental Protection Agency and the U.S. Department of Energy:

Stay in tune: When something seems off with your car and you aren't getting the mileage you're used to, a tune-up could make it as much as 40 percent more fuel efficient. While you're at it, replace dirty air filters (which can make your car up to 10 percent more fuel efficient) and have the oil changed (up to 25 percent efficiency improvement).

Easy, speedy: Every 5 miles per hour over 60 decreases your fuel efficiency by about 5 percent.

Pump them up: Your tires, that is. Keep them inflated to the recommended pressure; for every three pounds of pressure you drop below that, you lose about 1 percent of your fuel efficiency.

No more junk in the trunk: Don't use your car as storage space. An extra 50 pounds of stuff in your car causes a 1 percent decline in fuel efficiency.

Don't idle: Sitting still with the car on means you're burning gas and getting nowhere.

Oh yeah, Do less driving!: Sure, sometimes you need a summer road trip. But for day-to-day here-to-there, try walking, biking, carpooling, or public transportation. If you bike into Boston on Friday (or Aug. 22), you can get a police escort or guide - and a free breakfast at City Hall Plaza. See cityofboston.gov/bikes for details.

Green tip: Kids can learn more about green ways to get around at the Boston Children's Museum's Transportation Green Fair ( July 26, 11 a.m.-4 p.m. bostonkids.org).

Christie Matheson is the author of "Green Chic: Saving the Earth in Style."