I am looking for a movie that I remember I once saw when I was younger. I am not sure of the title or the year of the film, but I do remember that it involved some sort of dystopian future and there were military cargo trucks that drove themselves and would travel on long open desert roads stopping for nothing in their path with the exception of living objects. Whenever one of the trucks would encounter an obstacle, it would emit a computerized voice informing the obstruction that it was "In Violation". If the obstruction was a living object, the truck would come to a complete stop, however if the obstruction was inanimate, it would plow right through and continue its course. I remember one of the vehicles was carrying two people who managed to stowaway, and eventually the truck is hijacked after a small band of "soldiers" or "renegades" had forced the truck to stop after placing a live cow in the road. I only remember seeing the film once, several years ago on either Showtime or HBO, probably sometime between 1988-1992, though it could be much older than that. I do know that it is not "Maximum Overdrive". Any ideas and any insight would be appreciated. Thanks in advance.