Regulation 7 Placing of traffic signs
Where a build-out, chicane, island, pinch-point, rumble device or any combination thereof is constructed in a road, the roads authority for that road shall place and maintain traffic signs in such positions as are requisite for the purpose of providing adequate warning of the presence of such traffic calming works, unless those works are—
(a)
so constructed as themselves to provide adequate visual warning for persons using the road concerned; or
(b)
constructed on a road the speed limit on which is 20 miles per hour or less.