An issue at a BP refinery in Indiana and an uptick in road travel strained supplies, though retail prices are holding relatively stable overall, AAA said.

The motor club reports a national average retail price for a gallon of regular unleaded gasoline at $2.12, relatively unchanged from one week ago. For most of the summer, gasoline supplies have kept pace with consumer demand, though federal data last week show the steepest decline in those supplies since April as drivers take advantage of lower fuel prices.

In its weekly retail market report, AAA said market factors were somewhat offsetting supply issues and keeping the price at the pump in check since last week.

"With gasoline supplies high and oil prices low, pump prices are likely to remain relatively cheap through the remainder of the summer and into the fall," the report read. "This comes even as U.S. drivers are on track to shatter the all-time record for total miles driven in a year."

For most of the country, gas prices moved lower, but the Great Lakes states countered national trends as Michigan recorded the highest increase nationwide at 14 cents per gallon. The spike was in response to an increase in prices at the wholesale level because of problems at BP's refinery in Whiting, Ind., the largest in the region.

Problems at the Whiting refinery last year pushed some retail markets above $3 per gallon, though Michigan's statewide average price as of Tuesday was $2.32. The issue at BP's refinery was resolved by Friday.

On the market side, AAA noted the price for crude oil was below this year's peak above $50 per barrel. This week started with a call from members of the Organization of Petroleum Exporting Countries to hold an extraordinary meeting in September, and last week ended with chatter about a possible production freeze.

"Similar efforts earlier this year were unsuccessful, as members opted to preserve market share by maintaining production, which has preserved the global state of oversupply and resulted in low oil prices," AAA said.

Looking ahead, AAA said that, barring any unforeseen security issues or weather events like a hurricane, prices at the pump should move lower. Once the so-called summer driving season ends Sept. 15, the motor club said the national average price could drop below $2 per gallon.