The average price of regular-grade gasoline has surged 12 cents nationally over the past three weeks, to $2.38 a gallon.
Lundberg says the current price is 33 cents a gallon above what it was one year ago.
Gas in San Francisco was the highest in the continental United States at $2.78 a gallon on average Friday. The low average was in Denver, at $2 a gallon.
The U.S. average diesel price is $2.56, up 8 cents from three weeks ago.