I am trying to find a film that had futuristic cars that were powered by human beings (possibly that could not talk or a sub species). What I can remember is that a girl is picked up either unconscious or sleeping and is put into the boot of a car as a power source. Possibly 1980's.

Not sure if it matches exactly, but maybe:
Blood Car - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Blood_Car)