O9.6.8 Whenever convoy working is withdrawn, the reduced speed limit signs must be covered or removed until such time as convoy working resumes. Outside working hours temporary speed limit signs shall be covered or removed unless they are considered necessary to maintain safety within the site. A check should always be made to ensure that no conflicting signs remain in place at any time.
O9.6.9 Where safety concerns exist, consideration should be given to the need for a second temporary speed restriction (e.g. 40 mph) for use when the convoy works have been withdrawn temporarily.
O9.7RADIO COMMUNICATION
O9.7.1 There should be radio communications between the operators of the signals (or "STOP/GO" boards), operatives in the convoy vehicles, traffic control supervisor, and the works supervisor at all times. The role of traffic control supervisor may be combined with one of these other roles in appropriate circumstances. The main purposes of using radio communication are:
- to inform the signal (or "STOP/GO" board) operator of the time to effect a change;
- to tell the driver of the leading convoy vehicle when the end of the convoy has cleared the end of the 10 mph speed limit zone, allowing the speed to be increased; and
- to inform the works supervisor to suspend the work and re-establish the safety zone as necessary.
O9.7.2 All operatives should be fully conversant with the radio communication system and should be carefully briefed about their role and the agreed method of radio control.
O9.7.3 It has been shown that there are benefits to be gained by using precise predetermined radio instructions for the changing of the traffic control, dealing with emergency vehicles and other key steps in the operation of the convoy system.
O9.7.4 Operatives should take special care when operating radios that they maintain concentration on the driving task. Experience has shown that it can be beneficial to use an additional person in each vehicle to act as radio operator. This person also allows for frequent driver changes which aid concentration and alertness. Where an additional person is not provided, the radio should be capable of hands-free operation.
O9.8SIDE ROADS WITHIN THE SITE
O9.8.1 The works should be arranged to avoid junctions occurring within them. Where this is not reasonably practicable, the following procedures should be adopted.
O9.8.2 In all cases, except when there are high flows on the minor road, control of side road traffic should be provided by manually operated "STOP/GO" boards. (These boards must not be used during hours of darkness unless they are directly lit). The "TRAFFIC CONTROL AHEAD" sign to diagram 7010.1 should be erected on the minor road after a "road works” sign to diagram 7001. This procedure should be used only when traffic held at the works is visible to the joining traffic. The signs should be supplemented with convoy signs to diagrams 7025 and 7028 placed 100 m and 50 m respectively in advance of the junction. The "WAIT HERE" sign to diagram 7027 (using the “STOP SIGN” version of the legend) should also be placed at the junction stop or give way.
O9.8.3 The traffic control supervisor should advise the "STOP/GO" board operator at the side road by radio that the convoy is proceeding through the works. As the tail of the convoy passes his position the operator should signal the waiting side road traffic to join the convoy. The operator should ensure that vehicles joining from the side road do not travel in a different direction to the convoy. When the last vehicle in the side road queue has joined the convoy he should turn the sign to "STOP".
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