Page:UK Traffic Signs Manual - Chapter 8 - Part 2- Traffic Safety Measures and Signs for Road Works and Temporary Situations) - Operations 2009.pdf/102



Where the highway width is so restricted as to prohibit the provision of the appropriate lateral clearance detailed in Section, and diversion of traffic would be impracticable, traffic speeds should be reduced to not more than 10 mph and an agreed safe method of working imposed on the site. Convoy working provides such a method.

The design aspects are dealt with in Part 1: Design, Section D7 and the operational details, including the method of operation, are described in this section.

This method of working should preclude the use of workers in the safety zone wherever possible. Incursions into the safety zone increase the risk to workers and passing traffic on the highway.

Convoy working can be used on:
 * single carriageways where traffic travels either in a single direction, or in alternating opposite directions;
 * individual carriageways of two-lane all-purpose dual carriageway roads, where traffic travels in one direction only and works have reduced the traffic to single file; and
 * carriageways during surface dressing operations when it is considered necessary to ensure compliance with speed limits which have been implemented to protect newly-laid surface dressing.

Convoy working can be used for both day and night working.

Convoy working shall not be used on motorways.

Convoy working has been used successfully on single carriageways with two-way peak hour flows of 900 – 1000 vehicles/hour and on dual carriageways, where the one-way hourly traffic flow has typically not exceeded 600 vehicles/hour during the period of convoy working.

On single carriageways it has been found that, at flow levels approaching the value quoted in paragraph O9.1.7 above, it may be necessary to restrict peak-time working or make provision to withdraw the convoy periodically to disperse queues. In this event the work activity should also be suspended until the passing speed of traffic can again be reduced to 10 mph or less.

Those responsible for the design or implementation of a convoy working system should ensure that the proposed arrangements will prevent any traffic from exceeding 10 mph whilst passing the working space.

Signs to diagram 7003.1 giving advance notice of the commencement of the works shall be displayed at least seven days before work begins. If convoy working is to take place at night on a dual carriageway road, the "Night-time works Expect delays" sign to diagram 7002.1 should be placed two miles upstream of the works. This should be left in place during the day.

A limited number of works, such as gully cleaning, cats eyes replacement or cone maintenance may be carried out in the running lane between convoys under the protection of red-red signals or "STOP/STOP" boards. The traffic signals or manually operated “STOP/GO” boards at both ends of the works should be turned to "STOP" during this process.

Where works are allowed to encroach into the running lane, the traffic control supervisor should check by radio with the works supervisor that the running lane is clear before releasing the convoy. Similarly, the works supervisor should not allow works to recommence until the traffic control supervisor has confirmed 100