The most common question asked about the truck is “What kind of truck is it?” In spite of Director, Victor Salva’s comments on the DVD, it’s not a REO. It’s a 1941 Chevy COE (cab over engine) flatbed, similar to the one pictured here.
Three matching trucks were pieced together for the film. A truck with the original six cylinder engine and was used throughout the film, including some of the chase scenes (this is the one I own). Another truck was modified with an eight cylinder automatic engine and was used primarily for the chase scenes. The third truck had no engine at all and was only used for static shots.

truck #2 left, truck #1 right
Another misconception is that the truck is an old army MASH ambulance because of its box van rear. In fact, the entire box was constructed by the design team and “aged” to match the condition of the cabs, right down to the fake rust bubbles.
Project illustrator and original Creeper designer, Brad Parker, was chiefly responsible for the truck’s unique style. Brad’s concept was to create a rolling suit of armor for the Creeper with an almost medieval look.

Brad's concept drawing
Brad Parker (left) and truck #1 owner, Tim
Production designer, Steven Legler, was responsible for turning Brad’s vision into reality. The following shots show some of Steven and his design teams’ handy work on the set.
behind the scenes with truck #2

truck #1 left, truck #2 right