Peterson Motors Co. Located in Watertown, South Dakota, Peterson Motors continuously stocks over 180 semi-truck tractors, new and used semi trailers. We cater to farming, co-ops, over-the-road and construction industries as well as local and national heavy hauling needs. Your exclusive provider of the Quickveyor—the fastest, strongest, most advanced fertilizer trailer conveyor system on the market. Since 1989, we have been committed to providing the best products and services to meet your needs.