Orders of new medium-duty vehicles in classes 5-7 fell 21 percent to 17,300 units in April, reaching their lowest level in almost a year when compared to the same month a year ago, according to ACT Research.

"This was the lowest order intake since last July, but not out of line with several other months in the interim," said Kenny Vieth, ACT’s president and senior analyst.

Class 8 orders also fell, thought not as precipitously. When added to class 8 orders, classes 5-8 fell 6 percent in April to 39,700 units. The data is preliminary, and ACT Research will release its final report in mid-May.