Abstract: A system for controlling a cutting machine for cutting rumble strips in a road surface includes a rotatable cutting head, a cylinder for driving the cutting head out of and into contact with the road surface, and a controller. The controller is programmed to execute an input/output function for varying a proportional gain and an error amplification signal over a range of forward speed of the cutting machine. An I/O function is based on six predetermined cutting machine speed values; wherein a proportional gain and a depth increment are specified for each speed value. The respective speed values increase progressively. As an actual forward speed of the cutting machine varies between two of the six predetermined input speed values a linear interpolation is applied between the next lower and the next greater speed value to vary the instantaneous proportional gain and depth increment to be applied by the controller.