O11.4.8 Once the start point of the closure operation has been established, the location of the following should be identified:
- the assembly point, off the main carriageway, where the closure vehicles will assemble prior to the commencement of the closure operation; and
- the access point where the closure vehicles will enter the carriageway.
O11.4.9 At this stage, the number of vehicles necessary for the operation should also be determined. This is:
- usually one closure vehicle per lane plus a hard shoulder vehicle for the hard shoulder, where present;
- monitor vehicle;
- two advance warning vehicles; and
- if necessary, the signing equipment and/or vehicles necessary to close temporarily any access points.
O11.5CLOSING ACCESS JUNCTIONS
O11.5.1 Traffic access points in the path of the closure vehicles shall be securely closed for a brief period during the operation to prevent entry of traffic into the traffic-free zone ahead of the convoy. A Traffic Order will not be required for the slip road closure. The slip road is closed just before it is passed by the monitor vehicle and is reopened when the closure vehicles have passed it. See Section O11.18.
O11.5.2 The three options for closing the access slip road are shown in Plans MCC2, MCC3 and MCC4. The decision on which option to use at a particular site will depend on a number of factors including:
- the anticipated traffic flow on the slip road;
- the length of the slip road;
- the topography and sight lines at the junction (e.g. if the sight lines are poor then closing the slip road at its entry may be preferable); and
- the length, quality and signing of the diversion route should the slip road be closed.
O11.5.3 The usual option for closing the slip road, which is shown in Plan MCC2, will be a closure at its downstream end using a works vehicle (see paragraph O11.8.5) that is brought to a halt by a manually operated "STOP" sign to diagram 7023. There are two options for the type of works vehicle used:
- a vehicle fitted with impact protection; on a relatively short slip road linking a high-speed local road carrying high traffic flows to the motorway, it is likely that a risk assessment would show that a vehicle fitted with impact protection (see paragraph O11.8.5) would be most appropriate; or
- a vehicle not fitted with impact protection; on a slip road that is relatively long and that has good visibility and carries relatively little traffic, a vehicle with the same features as the one used to close the hard shoulder (see paragraph O11.8.4) is likely to be more appropriate.
O11.5.4 The option given in Plan MCC3, which involves personnel placing and removing coning and signing across a traffic lane, will only be appropriate when the traffic flows on the slip road are very low and a risk assessment has shown that this is the most appropriate option.
143
