Preliminary numbers indicate Class 8 commercial vehicle orders for North American markets climbed to 38,200 units in April, up 158 percent from year ago, according to ACT Research -- the largest monthly order intake since March 2006.

Preliminary net order numbers are subject to revision and are typically accurate to within 5 percent plus or minus.

"Every cycle has one or two of those months when the breadth of participation rises and a confluence of events leads to these types of results. April happened to be that month this cycle," said Kenny Vieth, president and senior analyst.

"The list of positive drivers leading to the April order spike is long: Healthy freight, increasing trucker profits, pent-up replacement demand, rising used equipment prices, improving credit worthiness, rising prices for new vehicles, and lead times for new equipment that have pushed out to the end of the year. If that was not enough, there is the accelerated depreciation schedule for 2011 to consider." Vieth continued, "The challenge now is for the industry to translate all of this demand into trucks."

ACT is a major publisher of new and used commercial vehicle industry data, market analysis and forecasting services for the North American market, as well as the U.S. tractor-trailer market and the China CV market.

Corrected 10 p.m. EDT 5/5/2011 to correct error in percentage jump in orders.