Page:UK Traffic Signs Manual - Chapter 8 - Part 2- Traffic Safety Measures and Signs for Road Works and Temporary Situations) - Operations 2009.pdf/20



At some sites, during the first few days of operation, low traffic capacity may be experienced until drivers become accustomed to the situation. It is important not to make inappropriate changes which may increase the risk to the workforce and road users during this period.

The extent of all excavations and temporary obstructions should be kept to a minimum and the aim at all times should be to complete the works as quickly and safely as practicable.

On motorways and dual carriageway roads subject to the national speed limit, operatives shall not make their way into and out of any traffic management arrangement using their own personal vehicles unless the vehicle is fully compliant with the appropriate requirements of Section O5.

The number of vehicles entering and leaving a site should be kept to a minimum at all times. Only essential works vehicles complying with the requirements of Section O5 should be allowed within the site. Provision for the parking of operatives’ personal vehicles should be made off site whenever possible.

For all roads with a permanent speed limit of 50 mph or more, the lateral clearance between the edge of the working space and that part of the carriageway being used by traffic should be not less than 1.2 m.

On single carriageways if the nature of the road is such that a lateral safety clearance of 1.2 m cannot be achieved, then the lateral safety clearance should be as wide as practicable with an absolute minimum of 0.5 m.

Where the lateral safety clearance is less than 1.2 m then a temporary mandatory speed limit of 40 or 30 mph will need to be put in place, using physical safety measures, in association with enforcement of the speed limit where appropriate, to ensure that traffic passing through the site does not exceed the temporary speed limit. These safety measures may include chicanes, temporary speed ramps, traffic control etc. Solely relying on a temporary mandatory speed limit as a safety measure is not deemed sufficient.

On roads other than motorways, if there is insufficient space to provide the minimum lateral safety clearance of 0.5 m, there are a number of available options.
 * If practicable, the road can be closed and traffic diverted along a suitable diversion route (see Part 1: Design, Section D3.15).
 * If diversion of traffic would be impracticable, traffic speeds must be reduced to below 10 mph and an agreed safe method of working imposed on the site; this must be agreed with the Highway Authority.
 * For short lengths of shuttle working, i.e. 50 m or less, on single carriageways, chicanes can be used. At least one chicane is required in each direction of the minimum size to allow a large vehicle to pass through slowly, and traffic must first be brought to a halt by positive traffic control and then released in small batches by careful use of "STOP/GO" signs or manually controlled portable traffic signals. See also Part 1: Design, Section D5.12.
 * On single carriageway roads with low traffic flows an extended all-red period with portable traffic signals or "STOP/GO" boards may be used. See Part 1: Design, Section D5.13. For a definition of "low traffic flows", see Glossary (Appendix 2). 18