When the vehicular traffic light signal at a “Pelican” crossing is showing a flashing amber light, every pedestrian, if he is on the carriageway, or a central reservation within the limits of that crossing (but not if he is on a central reservation which lies between two crossings which form part of a system of staggered crossings) before any part of the vehicle has entered those limits, shall have precedence within those limits over that vehicle and the driver of a vehicle shall accord such precedence to any such pedestrian.