Retail gasoline prices in the United States may be erratic as investors guess on what happens next with OPEC, though pain at the pump is diminishing, AAA said.

The motor club reports a national average retail price for a gallon of regular unleaded gasoline at $2.21 for Tuesday, relatively unchanged from one week ago and slightly higher than the national average reported for this date in 2015.

AAA said the national average has dropped for several straight days, but a decline that usually comes late in the year has yet to emerge in part because of dynamics in crude oil prices.

"Drivers may continue to see prices wobble up and down as traders speculate on the possibility of OPEC countries developing an output agreement over the next month," it said in its weekly retail market report. "Additionally, planned and unplanned refinery maintenance continues across the United States and may result in regional fluctuations in gas prices."

Crude oil prices moved up more than $8 per barrel in the immediate wake of a framework agreement from the Organization of Petroleum Exporting Countries that emerged from a meeting Sept. 28 in Algeria. Prices have moved up and down in response to rhetoric associated with that meeting, but collapsed more than $1.40 per barrel Monday after weekend OPEC meetings concluded without any concrete plans.

Crude oil prices account for the bulk of what consumers pay for gasoline.

By region, the West Coast market, the most expensive in the country, saw prices moving higher after BP shut down a regional pipeline, though that should restart in the coming weeks and bring some relief to area motorists before the Christmas holiday.

In the Great Lakes states, the most volatile market in the United States, prices have been relatively steady, but are moving lower after BP wrapped up maintenance at its refinery in Whiting, Ind., the region's largest.

"The refiner helps supply much of the Midwest and any drops in supply resulting from the planned maintenance will likely be balanced by a seasonal drop in demand," the motor club's report read.

Looking ahead, AAA said prices could still move in response to OPEC, whose members meet again to consider the so-called Algiers Accord on Nov. 30.

The U.S. Energy Information Administration said it expects retail gasoline prices to average around $1.97 per gallon in January. The full-year average next year may be around $2.26 per gallon, against the expected $2.12 average for 2016.