Plan T52: Transition section (single to dual), works starting between the start of the dual carriageway and 600 m downstream, approach signing on the single carriageway road
The principles for the approach signing are:
- a "road works" sign (7001) with supplementary plate "1 mile" (572) placed on the near side 1600m in advance of the works lead taper;
- a "road works" sign (7001) with supplementary plate "800yds" (572) placed on the near side 800m in advance of the first cone of initial lane closure;
- a "road works" sign (7001) with supplementary plate "400yds" (572) placed on the near side 400m in advance of the first cone of initial lane closure;
- a "road narrows” sign (517) with supplementary plate "200yds" (572) placed on the near side 200m in advance of the first cone of initial lane closure;
- a "keep right" sign (610) at the start of near side coning to Detail B, followed by coning to Detail C1;
- coning to Detail C1 at off side on the edge of hatched area;
- a "keep right" sign (610) and lane closure barrier sign (7105) should be placed in the closed carriageway at the start of the closed lane; and
- a "keep left" sign (610) at the start of the road markings hatched area, this should be protected from impact from opposing traffic by a short cone taper to Detail B within the hatched area.
Consideration should also be given to providing a "no entry" sign to diagram 616 on the off side at the end of the opposing traffic dual carriageway section.
Where sight lines on the single carriageway road are particularly poor, such as on a left-hand bend, a duplicate set of signs should be placed on the other side of the single carriageway.
The above is for a near side lane closure. For an off side lane closure the advance sign to diagram 517 should indicate the road narrows on the right ahead, the near side " keep right" sign to diagram 610 is not required, the off side lane closure coning (Detail B) commences at the start of the central reservation road marking hatching, no near side coning is required, and the "keep left/right” sign to diagram 610 should indicate that traffic should pass to the left.
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