1999, Chester Peterson, Rod Beemer, Inside John Deere: A Factory History, page 93,The fleet has 48 semi-tractors and 164 trailers that transport 110,000 tons of parts and supplies annually over 1 million miles of roads.
2003, Michael E. Gray, Auto Upkeep: Basic Car Care, page 56,Some people think diesel fuel is only used in semi-tractors (Figure 9.3) or heavy equipment.
2008, Raymond P. Siljander, Introduction to Business and Industrial Security and Loss Control, 2nd Edition, page 75,Security seal use applies when carrying merchandise in semi-truck trailers (highway trailers) pulled by semi-tractors and when railroad flatcars carry the trailers, the latter referred to as piggyback (piggybacking).
