A control system for positioning a marker over a pre-existing roadway surface mark. The control system has an electromagnetic radiation source attached to the marker for producing a mark pattern on the roadway surface. An imager permits the control system to image both the pre-existing roadway surface mark and the mark pattern produced by the electromagnetic radiation source. A computer is responsive to the imager for producing an error signal based upon the location difference between (a) the image of the pre-existing roadway surface mark and (b) the image of the mark pattern produced by the electromagnetic radiation source. An actuator is responsive to the error signal for positioning the marker over the pre-existing.