Abstract: An electro-hydraulic steering system for vehicles such as roller type surface compacting machines which have a steerable ground-engaging unit at each end of the chassis. The system combines a conventional orbital type steering valve, two conventional solenoid actuated hydraulic valves and two conventional lock valves with an electric control circuit that includes simple console-mounted selector switches, a foot pedal-controlled switch and a simple cam-actuated switch that is automatically actuated in consequence of shifting the control lever of the vehicle's transmission from "forward" to "reverse" and vice versa, in a manner which gives the operator unprecedented flexibility in his choice of steering mode.