Abstract: Modular motor vehicles are provided with a plurality of independently operable functionally different automobile and truck type core vehicles and a plurality of interchangeable functionally different body and chassis modules attachable to the core vehicles. The core vehicles utilize standardized first engagement means including frames and adapter plate elements connected to or "unitized" into the core vehicles. Said first engagement means of the cores have positioning elements and alternating connecting elements at standardized predetermined spacing and location defining a structurally rigid bed for the modules. The modules incorporate a second engagement means, located and spaced to compliment said first engagement means, making it possible to easily align, connect and disconnect the modules with respect to the core vehicles. The modules incorporate a third engagement means to align and connect the multiple-piece modules together.