Duel
Spielberg directs this edge-of-your-seat TV movie about a man terrorized by a crazed truck driver while driving to work. The film is based on a script written by novelist Richard Matheson, and stars Dennis Weaver.
I was intimately familiar with the work of Richard Matheson because I was a complete, obsessive-compulsive Twilight Zone follower, and so I knew of his work on the Twilight Zone and some of his really great episodes of that.