DESIGN CRITERIA
Plan TS4: Transition section (single to dual), works starting 850m or more downstream of the start of the dual carriageway, 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 and on the central reserve 800m in advance of the first cone of initial lane closure;
- a "lane closed ahead" sign (7202) with supplementary plate "400yds" (7208) placed on the near side and on the central reserve 400m in advance of the first cone of initial lane closure; and
- a "lane closed ahead" sign (7202) with supplementary plate "200yds" (7208) placed on the near side and the central reserve 200m in advance of the first cone of initial lane closure.
Consideration should also be given to providing a "no entry" sign (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.
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