The volume of sales of used heavy-duty (Class 8) commercial vehicles has slowed in recent months, declining 16 percent month-over-month in October according to ACT Research Co.

In its latest release of the State of the Industry: U.S. Classes 3-8 Used Trucks, ACT also reported that the average price for the units sold increased 4 percent month-over-month as buyers focused on the limited supply of low-mileage vehicles available.

"Tighter supplies of equipment of all sizes continue to be a boon for selling prices," said Steve Tam, vice president-commercial vehicle sector with ACT. "With the focus on late-model equipment, the average miles for Class 8 units sold were down 13 percent month-over-month and 14 percent compared to October of 2009."

ACT Used Truck database participants report approximately 2,500 transactions per month. The company is working with used vehicle market participants to push the number of reported transactions significantly higher. ACT estimates that approximately 10 percent of used Class 8 transactions are included in the database.