This is actually how (some) couriers worked in Neal Stephenson's Snow Crash. They latched on to the back of passing cars/trucks with magnetic harpoons and hitched a free ride until they needed to head another way.
You should, it's a great book. Published before Stephenson became (apparently) famous enough to ignore his editors and stopped cutting down his material... Both "Snowcrash" and "Diamond Age" are very good.