A GPS-based control system for positioning a projection of a material dispensing nozzle (84, 86, 88, 90) onto a predetermined roadway mark path located on a roadway surface comprising: a vehicle having an attached paint carriage which is laterally movable which respect to the vehicle; a material dispensing nozzle attached to the paint carriage; a first GPS antenna mounted on the vehicle; a first GPS receiver responsive to the first GPS antenna; a first signal processor responsive to the first GPS receiver for determining the geographical location of the first GPS antenna; a second GPS antenna mounted on the vehicle; a second GPS receiver responsive to the second GPS antenna; a second signal processor responsive to the second GPS receiver for determining the geographical location of the second GPS antenna; a third GPS antenna mounted on the vehicle; a third GPS receiver responsive to the third GPS antenna; a third signal processor responsive to the third GPS receiver for determining the geographical location of the third GPS antenna; a linear motion and position sensor for determining the relative lateral linear displacement of the paint carriage with respect to the vehicle; a GPS location processor responsive to the first, second and third signal processors (1500a, 1500b, 1500c) and to the linear motion and position sensor for determining the absolute GPS location of the material dispensing nozzle; a coordinate transform processor for transforming the absolute GPS location of material dispensing nozzle into a location in a coordinate system other than GPS; a comparator for comparing the location of the material dispensing nozzle in the coordinate system other than GPS to a desired roadway mark path according to the coordinate system other than GPS; and a control system responsive to the comparator for controllably positioning the projection of the material dispensing nozzle onto the roadway mark path by laterally moving the paint carriage. a vehicle having an attached paint carriage which is laterally movable which respect to the vehicle; a material dispensing nozzle attached to the paint carriage; a first GPS antenna mounted on the vehicle; a first GPS receiver responsive to the first GPS antenna; a first signal processor responsive to the first GPS receiver for determining the geographical location of the first GPS antenna; a second GPS antenna mounted on the vehicle; a second GPS receiver responsive to the second GPS antenna; a second signal processor responsive to the second GPS receiver for determining the geographical location of the second GPS antenna; a third GPS antenna mounted on the vehicle; a third GPS receiver responsive to the third GPS antenna; a third signal processor responsive to the third GPS receiver for determining the geographical location of the third GPS antenna; a linear motion and position sensor for determining the relative lateral linear displacement of the paint carriage with respect to the vehicle; a GPS location processor responsive to the first, second and third signal processors (1500a, 1500b, 1500c) and to the linear motion and position sensor for determining the absolute GPS location of the material dispensing nozzle; a coordinate transform processor for transforming the absolute GPS location of material dispensing nozzle into a location in a coordinate system other than GPS; a comparator for comparing the location of the material dispensing nozzle in the coordinate system other than GPS to a desired roadway mark path according to the coordinate system other than GPS; and a control system responsive to the comparator for controllably positioning the projection of the material dispensing nozzle onto the roadway mark path by laterally moving the paint carriage.