Market analyst ACT Research Co. predicts that both medium- and heavy-duty truck sales in North America will come off a weak 2009 to show modest growth in 2010 and “significant growth” the following year.

Compared to this year – which will record the lowest truck production numbers since 1991 – 2010 should bring a 22% increase in Class 8 vehicle production, according to ACT. Despite that growth, North American production for the coming year will still be below normal vehicle replacement levels, the company says.

ACT’s projections for 2011 are much more robust, showing a 69% increase over 2010 heavy-duty production levels for North America.

Medium-duty trucks, which ACT defines as Classes 5-7, should show year-to-year production growth of about 30% in both 2010 and 2011, according to the company.

 “There are still a number of hurdles to clear in the coming quarters, including continued excess trucking sector capacity, a soft used truck market, tight credit, and weak freight rates,” said Kenny Vieth, partner and senior analyst with ACT. “However, the fleet is aging and truckers are increasingly making comments about the condition of their fleets. When the freight market regains solid footing, the recovery in commercial vehicle demand promises to be vertical,” added Vieth.