Peterbilt Motors Co. says it will shutter its Madison, TN, assembly plant by Dec. 1.

“This was a difficult but necessary decision,” Bill Jackson, general manager-Peterbilt, says in a statement.

The closure of the Nashville-area plant, which has not produced any trucks since July 2008, is part of the truck maker’s North American capacity realignment.

“The current and projected market conditions are very challenging,” Jackson says of the reason for the plant’s closure.

Through August, Peterbilt’s Class 8 and Class 7 sales were down more than 30%, while Class 4, 5 and 6 sales have registered drops greater than 50%, Ward’s data show. In Classes 5 and 7, Peterbilt’s declines are higher than the segments’ total losses.