NEW YORK (CNN) - Last month's spurt in gas prices appears to have topped off nationally and will likely begin dropping, a national survey said Sunday.

Over the past three weeks, the average price of a gallon of self-serve regular rose just 0.14 cents per gallon, to $1.7205, said Trilby Lundberg, publisher of the Lundberg Survey, which tallied prices at about 7,000 gas stations nationally on Aug. 22 and Sept. 12.

"I'm calling that no change," she said. "The surge is over."

Lundberg credited a confluence of three factors for the stall in what had been a precipitous rise in gas prices in recent weeks: correction of regional shortages, a drop in the price of crude and the end to the summer driving season, when demand for gasoline typically peaks.

Between Aug. 8 and Aug. 22, the average price of gas in the nation zoomed nearly 16 cents per gallon, driven by an electricity blackout that shut several refineries and a pipeline break Aug. 8 that affected a number of Western cities, particularly Phoenix.

"Both of those have been corrected," said Lundberg in a telephone interview from her home in Camarillo, Calif.

In addition, the price of crude oil has dropped, with a barrel light sweet grade closing Friday at $28.27 per barrel on the NYMEX, the lowest price since spring.

"All point to lower prices at the pump," Lundberg said.

In the past three weeks, prices in Atlanta dropped 12 cents per gallon, to an average of $1.45 per gallon, the lowest in the country. San Francisco gas stations commanded the highest prices, at an average of $2.11 per gallon.

Here are some other prices: New Orleans - $1.53; Dallas - $1.56; Minneapolis - $1.66; Washington - $1.69; Salt Lake City - $1.79; Seattle - $1.87; Providence - $1.84.