October net orders of heavy-duty Class 8 commercial vehicles for North American markets were 18,914 units, up 24 percent month-over-month from September, according to ACT Research Co. That's the second highest monthly total since April of 2008 and the highest this year.

Medium-duty Classes 5-7 net orders also gained, posting 19 percent month-over-month growth.

In the latest release of the State of the Industry: Classes 5-8 Vehicles, ACT noted that only a brief one-month surge in October 2009 produced greater net orders, as some carriers sought to get the last of lower priced engines in advance of the EPA 2010 emission mandate that raised the price of new heavy-duty vehicles by about $10,000.

"While September gave a hint to increasing demand for Class 8 equipment, October orders provided the strongest sign yet that the transportation sector recognizes the need to replace aging equipment," said Kenny Vieth, president and senior analyst. "With production of equipment rising only slightly in October, the order backlog is now 29 percent above its trough earlier this year, a sign that the commercial vehicle manufacturing sector is getting healthier."