"After twelve years of research, the Ford Motor Company has completed an experimental automobile with a plastic body. Although its design takes advantage of the properties of plastics, the streamline car does not differ greatly in appearance from its steel counterpart. The only steel in the hand-made body is found in the tubular welded frame on which are mounted 14 plastic panels, 3/16 inch thick. Composed of a mixture of farm crops and synthetic chemicals, the plastic is reported to withstand a blow 10 times as great as steel without denting. Even the windows and windshield are of plastic. The total weight of the plastic car is about 2,000 pounds, compared with 3,000 pounds for a steel automobile of the same size."
Lastly, here are some links on the hempmobile from Toronto Hemp, Drug Library and Marijuana Library.