A signpost system includes a signpost system includes a signpost having a lower-most base end and an opposite upper end opposite the base end, a bore clamp including at least a traffic-side clamp member and a shoulder-side clamp member wherein the traffic-side clamp member is adapted to substantially mount flush into the traffic-side of the bore in the barrier and wherein the shoulder-side clamp member is adapted to mount onto the shoulder-side of the bore, and an elongate selectively adjustable tensioner extending from and between the clamp members for mounting the clamp members in the traffic-side and in the shoulder-side of the bore respectively, and wherein the shoulder-side clamp member is adapted for mounting to the base end of the signpost.