AAA reported a national average price for a gallon of regular unleaded gasoline of $3.54 per gallon, 7 cents lower than the same time last week and 15 cents lower year-on-year.
Last week, the motor group said it expected gasoline prices would increase, however, because of the potential for late-season hurricanes and refinery problems. Refinery issues in the Midwest and higher oil prices helped push gasoline prices above the $4 mark in the region early this year.
Drivers in the city of Chicago were still paying more than $4 as of Monday, however. Bloomberg News, meanwhile, reported Brent crude oil prices were down 0.16 percent in early trading to $108.05 per barrel.
The U.S. Energy Department last week said it expects the regular gasoline retail price to average $3.59 per gallon during the third quarter of the year. The average price for last year was $3.63 per gallon.
Trilby Lundberg, president of Lundberg Survey, told Bloomberg the steady decline in gasoline prices was because of an increase in U.S. refinery output.
"They have been producing so much gasoline that it verges on a glut," she said in an interview published Sunday. "To move these plentiful gallons, they have been slashing their wholesale prices to their marketers and retailers."