Plan DZB9: Lane-change zone for a lane closure and lane width restriction ahead on a dual carriageway road for which the national speed limit applies
Four pairs of advance signs are required:
For lane restrictions, other than simple lane closures, the "Restrictions ahead" signs (7201 and 7201 .1) are used incorporating symbols 7281 to 7288:
- 800 and 600 yards signs — top panel "GET IN LANE" (7262) and bottom panel "800/600 yards" (7271) on the near side and off side, placed 800 m/600m in advance of the works; and
- 400 and 200 yards signs — top panel "STAY IN LANE" (7263) and bottom panel "400/200 yards" (7271) on the near side and off side, placed 400 m/200m in advance of the works.
Where a temporary mandatory speed limit is in place, one pair of temporary speed limit signs is required, followed by repeater signs:
- the temporary speed limit sign (670), which will generally be 50mph, is to be placed on the near side and on the central reservation 50m in advance of the first sign indicating lane closures or restrictions (e.g. signs to diagram 7201, 7202, 7201.1), and
- for a temporary speed limit of 50mph the distance between successive signs on the same side of the carriageway should not exceed 700m, with a maximum of 450m between consecutive repeater signs on alternate sides of the carriageway. For temporary mandatory speed limits of 40mph or less, see Table 3.4, Note 1.
For entry taper details see Plan DZB8. Consideration should be given to the use of backlit sequentially flashing warning lights on the tapers to highlight the taper coning and distinguish it from the long straight stretches of coning (see paragraph D3.12.2).
Signing to Detail A is located on the hard shoulder opposite the "keep left/right" sign (610) at the start of the taper and opposite the end of the taper.
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