Where normal traffic management arrangements are not feasible because of restricted highway width, and diversion is impracticable, convoy working may be used. In this method, traffic is brought to a halt in advance of the works and is then led slowly in single file past the works by an appropriately signed works vehicle. If convoy working is to be used, the highway authority will need to be consulted well in advance of the works being undertaken.
Where there is little or no safety zone clearance, traffic speeds past the working space must be reliably reduced to 10 mph or less, and an agreed safe method of working imposed on the site. A risk assessment of the actual work activity and the effects of convoy working on the workforce and highway users must be conducted in order to determine whether this system is appropriate for the particular task and location.
Convoy working may be used during the hours of daylight or darkness and can be used on:
- single carriageway roads where traffic travels either in a single direction or in alternating 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 traffic speeds are low.
Planning for convoy working
The planning should include:
- early liaison with the highway authority. If the speed limit is to be reduced, a Temporary Traffic Regulation Order will be required;
- reference to Chapter 8 of the Traffic Signs Manual;
- consideration of how to keep disruption to a minimum;
- consideration for pedestrians, cyclists and other vulnerable road users;
- arranging the works to avoid junctions within the convoy section;
- a queue management strategy, including levels of congestion that trigger special action, and safe methods for the withdrawal of convoy working;
- determining the method to be adopted for the management of any side road traffic;
- establishing suitable locations for the convoy vehicle to pull out of the running lane at the end of the works;
- termination or suspension of any bus stops within the convoy section; and
- provision for access and services to premises within the convoy site.
Warning: The planning, installation and operation of a convoy working system must be undertaken by appropriately competent personnel. Convoy working can only be used with the approval of the highway authority.