Page:UK Traffic Signs Manual - Chapter 8 - Part 2- Traffic Safety Measures and Signs for Road Works and Temporary Situations) - Operations 2009.pdf/21

 *For longer site lengths a convoy working system should be used, see Section O9 and Part 1: Design, Section D7, Convoy Working.

For roads with a permanent speed limit of 40 mph or less the lateral clearance should be not less than 0.5 m.

The dimensions given above are the normal minimum lateral clearances required. Where it is reasonably practicable to provide additional clearance this should be done. In reaching a decision on what additional space, if any, may be provided, due regard should be paid to any possible consequences for the safety of road users and also to possible additional costs, including extra delay to road users. The latter will arise if there is insufficient capacity in the road space left available to traffic.

The provision of adequate lateral (sideways), longitudinal (longways) and vertical safety clearances between moving traffic and the works is an important element of temporary traffic management design and is dealt with in detail in Part 1: Design, Section D3.2.

Lateral and longitudinal clearances are measured at ground level, but apply above ground up to the headroom dimensions given in paragraph O3.2.19. The lateral clearance is measured horizontally between the edge of the working space and the edge of the carriageway in use by vehicles. It should be noted that the areas within the coned tapers should be regarded as parts of the safety zone as shown in Figure 3.1.

NOTE: The safety zone extends to the outside edge of the cones or the traffic edge of any road markings or studs that are present separating the live traffic lanes from the work area. 19