A system that includes an agricultural tractor that includes a steering mechanism for steering at least one surface-engaging member so as to cause changes in a direction of movement of the agricultural tractor； and an agricultural implement that is towed behind the agricultural tractor. The system further includes at least one forward sensor for sensing one or more objects or conditions located forwardly of the agricultural tractor and at least one lateral sensor for sensing one or more objects or conditions that when sensed are located laterally of the agricultural tractor or implement. The system further includes a controller that acts in dependence on at least one output of the at least one lateral sensor to take account of a presence of the one or more objects or conditions sensed by the at least one lateral sensor.
