U.S. average retail gasoline prices rose over the past two weeks to a record and could go higher as crude oil prices rise, demand increases and reformulations kick in, according to an industry analyst.

The national average for self-serve regular unleaded gas was nearly $2.0997 a gallon on March 18, up about 12.78 cents per gallon in the past two weeks, according to the nationwide Lundberg survey (search) of about 7,000 gas stations.

This beats the previous all-time high of May 21, 2004, of $2.0744 by 2.5 cents. In the past month, gasoline prices have increased 19 cents, virtually identical to the rise in crude oil prices. Prices have risen 33 cents in the past 12 months to $1.7716.

"Even if crude oil prices don't rise further, there are factors particular to gasoline that will mostly spell further hikes at the pump," said survey editor Trilby Lundberg (search).

Lundberg noted that drivers are heading out of the seasonally weaker winter months. "Demand builds up toward the peak driving months of June, July and August," Lundberg said.

She also noted that refiners will need to reformulate gasoline to accommodate regulations for the summer, which raises costs that are passed along to consumers at the pump.

At $2.34 a gallon, Honolulu (search) had the highest average price for self-serve regular unleaded gas, while the lowest price was $1.91 a gallon in Newark, New Jersey, although Lundberg noted that price was not strictly a direct comparison, as New Jersey offers no self-serve gasoline.