Abstract: A self propelled scale testing vehicle (20). The vehicle (20) includes a platform (22) supported about the surface of the ground by four wheels (34), the platform including a generally horizontal top surface portion for removably retaining plurality of calibration weights (24, 26). A low, sturdy rail structure (28) is positioned of the perimeter of the platform (22) for retaining the calibration weights (24, 26) thereon. A DC motor (48) is interconnected to the front two wheels of the vehicle (20) by a direct drive mechanism (50). A DC battery power supply (46) is electrically interconnected to the DC motor (48) for providing power thereto. A mechanical brake assembly (44) is interconnected to the direct drive mechanism (50) and includes drum (76) and shoes (80, 82). Mechanical steering mechanism (42) is interconnected to the back two wheels, the steering mechanism including a chain (102) and sprocket (104, 106) assembly. An operator platform (40) is provided proximate the back end of the vehicle (20).