Trailer orders in April were down 13 percent from March, but 3 percent above the prior year, according to ACT Research.

Year-to-date growth in net orders through April is 72 percent.

"While April was a little weaker than February and March, the trailer industry is in the early stages of a rebound from a very weak 2009," said Kenny Vieth, ACT senior analyst and partner. "A potential indicator of continued improvement is the very low level of order cancellations over the past three months."

In the latest release of "State of the Industry: U.S. Trailers," ACT noted that overall net orders continue to supersede build rates, which have boosted the order backlog to the highest level in 20 months.

Net orders of dry vans and reefer vans, the largest volume categories, each softened slightly in April compared to March, while flatbeds and other specialty segments continued to gain strength.