Page:UK Traffic Signs Manual - Chapter 4 - Warning Signs. 2013.pdf/18

 These signs may be used on all roundabouts other than mini-roundabouts. In practice it will not be necessary to use them at the very smallest roundabouts, provided the speed limit is 30 mph or less, the diagram 606 arrow being sufficient. They should normally be used whenever the diameter of the central island exceeds 8 metres.

3.21 It the sign is used in the central reserve or on the off side of a slip road on the immediate approach to a roundabout, it should not be sited where it would impair the driver’s view of circulating trafic.

Diagrams 515.1 and 515.1A are made from flexible material and designed to recover when struck by a vehicle. In other respects these signs are similar to diagram 515. Their use at particularly vulnerable locations might help to reduce maintenance costs.

The sign to diagram 515.2 is formed of block paving on the perimeter of a roundabout. It must always be accompanied by a vertical sign to diagram 606 facing each approach, but the paving may be used together with or in place of diagram 515 or 515.1A. This arrangement may be used on any roundabout with a diameter of 4 metres or more. The larger width of chevron (600 mm) should be used when the space between adjacent chevrons is equal to or greater than 1200 mm. In such cases either eleven or thirteen courses should be used. The white blocks must be reﬂectorised. Authorities considering such installations should take the maintenance implications of dirt and weed control into account. 17