An automatic steering control system was designed, installed, and tested on a coal mine shuttle car. The system utilizes sensors and associated signal processing electronics developed under a previous phase of this contract. The automatic steering system performs the routine guidance functions of turning corners and straight-through tramming. The shuttle car driver retains full authority of speed, braking, load, and unload functions and at any time may exercize his option with manual override or steering. Steering information is generated from signals derived from the existing lateral guidance sensor subsystem, and all operational features of the previously developed open-loop system are retained. Aboveground system tests were conducted in a simulated mine constructed of wood panel ribs. Results were in good agreement with prior hybrid computer simulations undertaken to validate the basic control system over a broad range of conditions and to select system parameter values.