Philadelphia-area gasoline prices approached $4 a gallon this Memorial Day weekend after crude-oil prices spiked to a record $135 per barrel.

"Almost every day we're hitting a record," said Catherine Rossi, spokeswoman for the American Automobile Association's Mid-Atlantic chapter, which is tracking summer gas prices with a weekly report.

As of yesterday, gas in Philadelphia and its Pennsylvania suburbs averaged $3.95 a gallon, up from $3.82 last week, $3.55 a month ago, and $3.12 a year ago.

In South Jersey, where gasoline taxes are lower, pumps averaged $3.80, up from $3.65 last week, $3.39 a month ago and $2.93 a year ago.

"Memorial Day weekend is, to convenience stores who sell gasoline, what Black Friday is to shopping mall-based retailers," Rossi said. "It is typically a big-volume weekend that sets the pace for sales for the rest of the season."

Gasoline refiners and retailers are being squeezed by high crude-oil prices due to demand in China and other growing economies, the declining value of the U.S. dollar compared to other currencies, and the rising cost of finding new oil supplies.

Higher prices last winter reduced consumers' demand for fuel, which made it less profitable for refiners to make more gasoline, and more profitable to make other products, Sunoco officials told investors in a conference call May 1.

But the federal Department of Energy said last week that Americans in recent weeks had been using more fuel than expected, given the high price.

"There are no physical shortages of oil," Royal Dutch Shell's chief executive, Jeroen van der Veer, told the Reuters news service last week. "There are no cars waiting at gasoline stations because they are out of stock. This has to do with psychology in the markets," he said, predicting that oil-price inflation could continue indefinitely.

Contact staff writer Joseph N. DiStefano at 215-854-5194 or jdistefano@phillynews.com.