Ridden Horses Road Sign Post Mounted 550.1 R2/RA2 (Face Only)The use of diagram 550. 1 should alert drivers of where it is common for accompanied or ridden horses crossing or using the road ahead. This is common in country lanes or where bridleways cross a road. Where wild horses are present, "Wild Horses Likely In Road Ahead" 550 should be used, or where horse drawn vehicles are common, "Horse Drawn Vehicles Likely In Road Ahead" 550. 2 is used instead. This warning sign can be used with a supplementary plate