The national average price of unleaded gasoline jumped 5 cents to $2.49 per gallon in the first week of 2018 and has reached a level not seen since 2014 during the week that starts the new year, according to AAA.

Heavy travel over the holidays drove gasoline prices higher, and drivers in the Northeast, South and upper Midwest are paying as much as 13 cents more than they were at the end of 2017. Prices should begin to fall, said Jeanette Casselano, AAA spokesperson.

"Although prices at the pump shot up over the holidays, now that the holiday season in the rearview mirror, motorists can expect gas prices to trend cheaper this month as we are likely to see a significant drop in gasoline demand," Casselano said.

Gasoline demand reached 9.5 million barrels per day, which is typical of the holiday season, according to a U.S. Energy Information Administration report. Historical data shows that demand will fall below 9 million barrels in January and remain at that level for the first several months of the year.

States with the largest increases from a year ago include Alaska (39 cents), Montana (35 cents), California (34 cents), Oregon (30 cents), Hawaii (27 cents), Washington (24 cents), Wyoming (24 cents), Indiana (23 cents), Nevada (22 cents), and Utah (22 cents), according to AAA.

States with the least expensive gasoline include Missouri ($2.22), Oklahoma ($2.22), Alabama ($2.22), Arkansas ($2.23), Mississippi ($2.23), South Carolina ($2.24), Texas ($2.24), Louisiana ($2.26), Tennessee ($2.26), and Kansas ($2.28).

Meanwhile, the price of a gallon of diesel increased 7 cents on the week to $2.973, which is 38.7 cents higher than a year ago.