Abstract: The invention is concerned with an improvement in a hydraulic steering system for an articulated vehicle of the type which comprises a main steering valve system which directs fluid introduced thereto from a fluid source to a steering motor system responsive to an output of a steering pump apparatus. The improvement comprises an articulation angle pump and an associated conduit system connecting the articulation angle pump parallel to the steering pump system to make the steering valve system responsive to a difference in flow between the steering pump system and the articulation angle pump. Alternately or additionally the improvement can comprise a hydraulic accelerometer and associated accelerometer conduit system in parallel to the steering pump system to make the steering valve system responsive to the output of the steering pump system plus a signal determined by the hydraulic accelerometer.