Traffic Queues Likely Ahead Post Mounted Sign - Dia 584 R2/RA2 (Face Only)The queues likely road sign to diagram 584 is designed to be used only on high speed roads where you may suddenly come across unexpected queueing traffic. For example where traffic builds to a junction over the brow of a hill, round bends or on a busy motorway junction. The sign should be placed far enough ahead of where the danger may be to give the driver enough warning that stationary traffic could be just around the corner. Queues are to be