Plan DZD4: Works zone showing a buffer zone
The principles for marking the running lanes on the primary carriageway alongside the works area are:
- coning to Detail F is used — if existing carriageway markings are suitably located and in good condition then Detail C1 may be used; and
- a sign indicating the number of lanes open to traffic (7205) with distance plate (7209) is required; this combination is repeated every 1/2 mile on the near side of the carriageway.
If a section of the works zone is used purely for access then consideration should be given to placing a "keep left/right" sign (610) on the approach to any works area located after the access. The designer shall assess if additional 610 signs are needed where specific risks in the works zone or changes in road geometry would justify additional guidance to road users.
The principles for marking the running lanes on the secondary carriageway are:
- if the running lane is adjacent to a buffer zone, then cylinders and studs to Detail H are used; (coning to Detail E is used at the diversion of the primary carriageway, to and from the buffer zone, whilst coning to Detail F is used on the secondary carriageway in advance of and following the buffer zone);
- where the diverted carriageway is adjacent to a buffer zone, signs indicating the number of lanes open to traffic and off side contra-flow working (7203) with distance plate (7209) are placed on the central reservation for primary carriageway traffic using the secondary carriageway; if HGV restrictions apply then this sign is replaced by the restriction sign (7201 .1) which can incorporate symbols 7280 to 7284.1 and 7288 as appropriate;
- in the secondary direction a sign indicating the number of lanes open to traffic and off side contra-flow working (7203) with distance plate (7209) is required; this combination is repeated every 1/2 mile on the near side; and
- if a temporary vehicle safety restraint barrier is used to separate opposing flows, signs to diagram 7203 must be replaced by diagram 7205 (or 7204 if the hard shoulder is used as a running lane).
A temporary mandatory speed limit will be in place; signs to diagram 670 should be continued from the lead-in zone; for the spacing of speed limit repeater signs, see Table 3.4, Note 1.
No relaxations apply.
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