Page:UK Traffic Signs Manual - Chapter 3 Regulatory Signs. 2008 (Second Impression 2008).pdf/24

COMPULSORY AND PROHIBITED MOVEMENTS

Where a sign to diagram 606 pointing to the left or to the right is required, it is always sited opposite the junction or on the central reservation of a dual carriageway road (see figures 4-1 and 4-2), unless it is mounted on a traffic signal head. When pointing upwards, the sign to diagram 606 is sited immediately before the junction, not in advance and not on the far side of the junction (except when mounted on a secondary signal head).

A sign to diagram 609 is usually mounted in advance of a junction at a distance of approximately 50m. This distance might need to be varied if another junction intervenes or where there are other constraints. In one-way roads that are wide enough for two lanes of traffic, the sign should be sited on both sides of the road. Where the ahead manoeuvre is prohibited and traffic can either turn left only or right only (see paras 4.8 and 4.10), the sign should be sited immediately before the junction on the left hand side (see figure 4-7) and may be duplicated on the right hand side of a one-way road or on a central refuge in a two-way road.

A prohibited turn sign to diagram 612 or 613 is always sited immediately before the junction on the left hand side. Where there are two or more approach lanes and a "no right turn" sign is likely to be obscured by vehicles in the near side lane, the sign should be duplicated either on the right hand side of the road or on any central refuge. There might be other situations where it would be helpful to duplicate either the "no right turn" or "no left turn" sign, e.g. where the near side lane is reserved for buses and the left turn is prohibited. On dual carriageways, signs should normally be mounted on both the left hand side and the central reservation. At a signal-controlled junction the sign should be mounted on the primary and secondary signal heads.

The sign to diagram 606 pointing to the left may be used without a traffic regulation order on central islands of roundabouts, where it is normally accompanied by the deviation of route sign to diagram 515 (see Chapter 4, paras 3.12 to 3.22). On very small roundabouts, other than mini-roundabouts, the sign may be mounted in a traffic bollard, in which case it will normally have a diameter of 270mm.