For yet another week, the national average has decreased, rewarding those motorists holding off on vacations until the second half of the summer. In the last week, national gas prices have fallen to an average of $3.47/gallon, some 8.3c/gallon lower than a year ago, when prices averaged $3.55/gallon.

"Motorists taking those late summer vacations continue to see their risk paying rewards: gasoline prices continue to hold near the lowest levels of the summer," said GasBuddy.com Senior Petroleum Analyst Patrick DeHaan. 

The West Coast remains the most expensive area for gasoline prices, as Oregon, California, and Washington take the top three spots, respectively at $3.898, $3.893, and $3.889/gallon. Other states nearby also remain expensive- Idaho stands at $3.76/gal, and Nevada at $3.77/gal.

"It's relatively rare to see prices holding lower in the mid-to-late summer, as hurricanes tend to weigh on prices and demand for gasoline is highest during the second half of the summer. However, oil prices rallied in mid-June, altering the behavior of gasoline prices, and after the situation in Iraq cooled, it let to a widespread selloff in commodities that led to cheaper oil prices and refineries passed the savings onto motorists. Prices today versus last year are lower in many communities across the country. Meanwhile, the Great Lakes has seen its low prices thrust higher after several refinery issues and planned maintenance culminated at the same time, leading to a drop in available supply, leading to higher prices. The best news is that as the driving season concludes, prices are likely to drop- most significantly in late September through the holidays," DeHaan said.

The cheapest gas prices in the nation continue to be found in the South: South Carolina stands at $3.16/gal on average, Alabama at $3.20/gal, Mississippi at $3.21/gal, Tennessee at $3.23/gal, and Louisiana at $3.24/gal.