Page:UK Traffic Signs Manual - Chapter 8 - Part 1 (Traffic Safety Measures and Signs for Road). Designs 2009.pdf/140



NOTES:
 * 1) The signs shown are those specifically required for chicanes and a 10mph mandatory speed limit. These supplement normal signing for either "STOP/GO" boards or temporary portable traffic signals.
 * 2) The principles in this plan are only appropriate for short lengths of shuttle working, i.e. 50m or less. For longer lengths, a convoy working system must be used, see Section D7, Convoy Working.
 * 3) In the event that the signs are on "STOP/STOP" for any reason, e.g. a materials delivery, there is a risk that drivers might be able to see both "STOP" and "GO" signs facing them. Therefore, the "STOP/GO" signs should be sited to minimise the risk of drivers seeing both "STOP" and "GO" signs facing them.

On single carriageway roads with low traffic flows an extended all-red period with portable traffic signals or "STOP/GO" boards may be used to allow a short period for certain works tasks to be carried out on the whole of the carriageway. For a definition of "low traffic flows", see Glossary (Appendix 2). Examples of work where the use of an extended all-red period that may be appropriate are installing traffic management, including temporary safety barriers, white-lining and tree felling.

To minimise queuing on the approach to the works, the all-red period used should always be the minimum needed in order to carry out the works task. As part of the design process, it is essential to first establish the likely traffic flow at the site when the works are planned in order to calculate the maximum number of vehicles that are likely to be delayed in a queue. Table 5.7 below gives example queue lengths for a range of all-red periods, depending on the traffic flow. 139