The average price for self-serve regular gasoline is now between $2.85 and $2.87, according to two national surveys of thousands of stations. That's the highest level since Aug. 6. For comparison sake, the current average gas price is about $1.35 more per gallon now than in April 2003.

The lowest price is $2.49 in North Ridgefield, Ohio, and the highest price is $3.59 in New York City, according to a survey of about 7,000 stations by GasPriceWatch.com. Hawaii, California, and Nevada are the states where gas is generally most expensive.

So, how can you save gas money on a road trip?

U.S. News & World Report has a list of 10 ways to cut your fuel costs.

Their tenth tip is to shop online for gas. This is more practical when you're taking a road trip to an unfamiliar area than when you're simply traveling around your hometown.

As this blog has previously reported, it's easier than ever to find stations selling cheaper gas. Several online mapping services, such as Mapquest and www.aaa.com/gasprices, now let people print out driving directions that mark the locations of gas stations on maps—and say what the latest gas prices are at those stations.

Mapquest recently added gas stations—and their prices—to its service. Find it by clicking here. If you prefer Google Maps, consider using this "mash-up" Google map here.

AAA has begun to let nonmembers use its online mapping tool to find the cheapest gas stations for any road trip. AAA has long offered printable maps and driving directions, but in the past year it has added to its maps the locations of gas stations—and even the per-gallon prices for gas at these stations. AAA's online service is fast, free, and easy to use. Visit AAA's main website, click on the TripTik link, and then enter your zip code and itinerary. The site will fetch turn-by-turn driving directions, detour suggestions, and other travel information. Next, look at the top left-hand corner of the screen and click on the button that says Show. From the drop-down menu that appears, select Gas.

Now you'll see gas stations along your route when you scan your online map displaying turn-by-turn directions. If you wave your cursor over any gas station icon on the map, the recent per-gallon price for gas at that station will appear. (AAA, like Mapquest, uses daily data from OPIS, a service that collects and provides fuel price data.) Click on the gas stations that will make the most convenient pit stops. The website will add those gas stations to your printable map.