The national average price of regular unleaded has remained flat at $2.86 per gallon for the week ending Aug. 13 in which consumer demand fell and gasoline inventories increased for the first time in six weeks, according to AAA.

On the week, the U.S. Energy Information Administration reported an increase of 3 million barrels of gasoline inventory. For the week, pump prices are an average of 1 cent lower than a week ago, 3 cents lower than a month ago, and 51 cents higher than a year ago.

"With a flat national average, U.S. gasoline supply and demand suggest they are balancing," said Jeanette Casselano, AAA spokesperson. "But that’s not to say that we could not see spikes in demand closer to Labor Day as motorists squeeze in those final road trips."

States with the most expensive markets include Hawaii ($3.76), California ($3.61), Washington ($3.39), Alaska ($3.36), Oregon ($3.27), Idaho ($3.22), Nevada ($3.19), Utah ($3.12), Connecticut ($3.06), and Pennsylvania ($3.06).

States with the largest weekly changes include Ohio (down 10 cents), Indiana (down 8 cents), Michigan (up 7 cents), Idaho (up 7 cents), Florida (up 6 cents), Utah (up 4 cents), New Mexico (up 4 cents), Missouri (down 3 cents), Delaware (down 3 cents), and South Carolina (down 3 cents).

Meanwhile, the national average price of a gallon of diesel fell six-tenths of a cent to $3.217, which is 61.9 cents higher than a year ago.