USA Today recently put out a great in-depth report on short-haul trucking out of LA, called "Rigged". These are not the 18-wheelers you pass on a cross-country road trip, but rather trucks that take goods from a port in Southern California to local warehouses and rail yards: "one small step on their journey to a store near you."
After taking on unexpected debt at the behest of their employers, these short-distance truckers became embroiled in what has been described as a modern day form of sharecropping: coerced into debt by employers who then used that debt to exploit them, and to keep the workers captive.