(RALEIGH) -- Are 4-dollars-a-gallon gas prices coming to North Carolina? Some forecasters think so, and prices have already risen 20 cents per gallon since Christmas. Tom Crosby of Triple-A Carolinas said there are several reasons for the increase.

"Number one is the economy is starting to recover. Number two, there's worry about the Iranian threats in the Persian Gulf interrupting shipments of oil, and I think the third thing of course is we have had a gas tax increase for gas that contains ethanol," he said.

North Carolina's current gas tax rate of 38.9 cents per gallon is one of the highest in the country.