(NBC News) Across the country gas prices rose again overnight Monday by an average of two cents.
At $3.64, the price is up 15 cents in a week.
The higher prices are here despite soaring U.S. domestic oil production.
American oil is being pulled from the ground at record rates in states like North Dakota, but you'd never know it at gas stations.
That has Senators upset.
"The lower crude oil cost from the new sources of production are not getting through, not getting through to the consumers' wallet at the pump!" Oregon's Senator Ron Wyden noted during Monday's hearing.
Oil companies say one reason is corn.
The government requiring 10% renewable fuel, ethanol made from grain, in every gallon of gas, and the cost of corn and the like is rising.
The also say the tornados in May disrupted oil refining, unrest in Egypt could slow oil shipments, and U.S. refineries are selling more overseas.
That means as American families hit the road for vacation, gasoline costs 24 cents more per gallon than it did last July, and the Department of Energy predicts another 15 cent per gallon rise is possible soon.
-- Steve Handelsman, NBC News, reports