The national average for regular unleaded as of Wednesday, July 28, was $1.90 a gallon, up 38 cents from the national average the same day a year ago, according to the American Automobile Association.
Other highs and lows for July 27:
The averages are provided by , of Heathrow, Fla., which monitors credit card transactions at 60,000 self-serve gasoline stations nationwide. The automobile club posts them on its Web site, .
of Dayton, Ohio, which gathers more than 70,000 prices submitted by spotters nationwide, reports the highest and lowest prices in the country.
Autonews.com will update gasoline prices in the United States twice each week throughout the summer.