In the DVD documentary, Spielberg observes that the fear of the unknown is perhaps the greatest fear of all and that Duel plays heavily to that fear. Throughout the film, the driver of the truck remains anonymous and unseen. His motives for targeting Weaver's character are never revealed.
To complement this concept, Remixed by Jorge has eliminated the reasuring voice over, we eliminated the restaurant stop and tightened up all the action.
Despite its simple plot, a low budget (only $375,000) and very short filming deadlines (originally 10 days), the movie maintains a high level of suspense due to Spielberg's taut direction, tight editing and the script's refusal to resolve the central mystery of the driver.