Abstract: In a vehicle housing with a chassis and ground-engaging wheels suspended therefrom, the improvement of an elongated housing including modular front and rear sections, a top or roof section, and side sections on opposite sides of the housing, each section having inner and outer substantially rigid plastic skin members in closely spaced parallel relation to one another and a lightweight filler material between the skin members, beam members at spaced intervals to one another along the side sections, flanges interconnected along the adjoining peripheral edges of the sections, and a floor section rigidly mounted on top of the chassis with connecting members for rigidly attaching the front rear as well as side sections to outer peripheral edges of the floor section.