Quick answer
The power unit (engine + cab) of a tractor-trailer combination, which pulls one or more trailers.
Class 8 tractors are the standard OTR power unit in U.S. trucking.
Learn more: The Complete Truck Equipment Guide
Glossary
Tractor
Related terms
- Conestoga TrailerA flatbed trailer with a retractable tarp on rolling rails that protects freight while allowing side and overhead loading.
- Dry VanThe most common enclosed trailer in U.S. freight, typically 53 feet long, used for general non-temperature-controlled freight.
- Flatbed TrailerAn open trailer with no walls or roof, used for steel, lumber, building materials, and oversize freight.
- Heavy HaulFreight that exceeds standard weight or dimension limits, requiring permits, route surveys, and often escorts.
- Hot ShotSmaller-scale expedited freight hauled by a Class 3–5 truck (typically a dually pickup with a gooseneck trailer).