U.S. drivers are relying more on credit cards to cushion the pain of high gasoline prices than they have in the past, according to the National Association of Convenience Stores (search).

Convenience stores, which sell about three-quarters of all gasoline sold in the nation, have seen the use of credit card purchases for motor fuel rise to 70 percent from about 54 percent last year, according to the industry group.

And drivers are seen reaching into their pockets for plastic more often as they try to stretch their budgets.

"Consumers are trying to displace the pain for a few weeks," said Jeff Lenard, a spokesman for the group which includes stores owned by oil companies.

U.S. gasoline prices (search) continue to reach new heights as crude oil prices climb on strong demand and U.S. refineries are running flat out to make enough gasoline to keep gas tanks topped off.

According to travel club AAA (search), the national average price for a gallon of unleaded gasoline hit a record of $2.614 a gallon Monday, up from the $1.881 a year ago.

And with a credit card, that $2.60 plus a gallon can easily morph into $3.00 a gallon if the consumer doesn't pay off all charges immediately and finance and interest charges start to accrue.

High gasoline prices have also caused many drivers to trade down in the fuel they use to fill up their vehicles. Sales of premium and mid-octane gasoline have tanked over the past few years as use of regular unleaded has risen, a trend which shows no sign of abating as prices continue to rise.

In 1998, one in every three gallons sold in 1998 was high octane. In 2003, this was down to one in five, according to convenience story group.

But some relief is in sight: The end of summer not only means fewer drivers but also less expensive gasoline, as the specifications change to make cheaper winter grade gasoline.

The savings? About five cents a gallon, Lenard says.