An installation head is mounted on a vehicle and moves along and adjacent to a roadway as the vehicle moves along the roadway. The head has a loading station at the bottom of a vertical loading chamber and a slide that slides along a floor to move markers out of the loading station into a setting station. A setting ram forces markers down onto adhesive prepositioned on the roadway. A plurality of heads may be positioned on the vehicle and may form opposite rows for simultaneously installing markers on opposite sides of a traffic lane. An indexed marker that interlocks with adjacent markers to prevent tilting may be used to maximize the reliability of the system. Various types of delivery devices may be used to deliver markers to the loading station. These include a delivery platform or carrousel positioned above the loading chamber to deliver markers down into the loading chamber. They also include a collating tape that delivers markers into the loading chamber through a side opening.