COLUMBUS, Ind. — Net orders of Class 8 trucks rose 38% month-over-month in November, according to the latest stats from ACT Research.

Medium-duty orders also enjoyed a strong November, up 28% month-over-month.

Class 8 orders reached their highest total in more than four years, noted ACT Research in its State of the Industry: Classes 5-8 Vehicles report.

Meanwhile, the backlog for new units has risen by nearly 10,000 units despite ramped up production from OEMs.

“The ramp up in orders over the past three months suggests that the barriers to increasing heavy-duty demand are being surmounted, setting the stage for a healthy demand rebound in 2011,” said Kenny Vieth, president and senior analyst. “While the hurdles have been significant, the facts are that tight capacity and improving shipment volumes are allowing carrier profits to rise. And the fleet is as old as ever, so a portion of those profits are going to replace those aging trucks.”