A motor vehicle is provided with a driving status discrimination device, which includes a steering angle sensor for detecting the rotational angle of a steering wheel and a microcomputer for reading and processing the steering angle signal each time the vehicle runs a predetermined distance. The microcomputer identifies one of steering angular ranges of intervals to which each detected steering angle belongs so as to record the frequency at which the steering wheel was turned to each steering angular interval. The microcomputer modifies the frequency for each steering angle interval with a weighting coefficient determined for the steering angular interval and then, calculates a total or integrated value of the modified frequencies for the steering angular intervals. Further, the microcomputer discriminates town street driving from mountain road driving based upon the integrated value so that the assisting power generated by a power steering mechanism of the motor vehicle can be controlled based upon the result of such discrimination.