(Iowa) -- Gas prices continue to fall in Iowa to start the week. Triple A reports the average price in for regular unleaded in Iowa is $3.10 a gallon, a drop of 15 cents from this time last week. The average price for regular in Polk County in Central Iowa and Scott County in the Quad Cities area is below 3 dollars a gallon, at $2.83 and $2.92, respectively. Gas is more expensive in the Iowa City/Cedar Rapids area with the average price in Johnson County is. $3.36 a gallon, just 4 cents below the national average. In Linn County, the average price for a gallon of regular is $3.20.