Auction action and healthy wholesale activity pushed sales volumes of used Class 3-8 commercial trucks in September after an extended summer slump, reported ACT Research. Retail markets fell, however.

The update on the used market was reported in the latest release of ACT's State of the Industry: U.S. Classes 3-8 Used Trucks.

"The majority of this month's sequential improvement can be attributed to a very solid month in the auction segment," said Steve Tam, vice president-commercial vehicle sector with ACT. "The average selling price for total used Classes 3-8 fell month over month.

"Average age continues to be the most consistent, least volatile of all the metrics measured," he added. "Both age and mileage numbers are expected to increase throughout 2011."

The report from ACT provides data on the average used price for the top-selling Class 8 model for each of the major truck OEMs.