We've probably all heard the term "tractor trailer" used when talking about massive semi-trucks. The two names get tossed around so often that they've become interchangeable, begging the question of ...

SAN DIEGO (FOX 5/KUSI) — A semi tractor-trailer jackknifed while traveling on northbound Interstate 15 Saturday morning, according to a Sig Alert from California Highway Patrol. The incident was first ...