Page:UK Traffic Signs Manual - Chapter 8 - Part 2- Traffic Safety Measures and Signs for Road Works and Temporary Situations) - Operations 2009.pdf/117

 When working vehicles or personnel are operating on the hard shoulder a block vehicle with a LMCC is required. The working vehicles should carry a "keep right" sign to diagram 610, which should be 1500 mm diameter unless this is not practicable in which case the largest possible sign should be used. The block vehicle on the hard shoulder should carry a sign to diagram 7403 or the recommended alternative light arrow sign. See Section O10.8 below. The light arrow sign shall not display any form of arrow when on a twoway single carriageway road and, other than at the scene of an incident, the light arrow sign shall not display any form of arrow when on a hard shoulder of a dual carriageway. If the works vehicle carrying the sign to diagram 7403 (or the higher visibility alternative) is substantial (e.g. a gully emptier or sweeper) and is fitted with a LMCC, the block vehicle may be dispensed with.

Regulation 14 gives details of the signs that may be attached to vehicles. The light arrow sign is not listed in regulation 14 and so needs separate signs authorisation and type approval from the appropriate Secretary of State.

Signs on the carriageway should always be vehicle or trailer-mounted and attended at all times. Signs on the verge may be vehicle or trailer-mounted or static and need not be attended.

All traffic signs used in connection with this technique must comply with the relevant requirements of the Traffic Signs Regulations and General Directions 2002 (TSRGD), the Lighting Regulations and BS EN 12899-1:2007 "Fixed, vertical road traffic signs" and BS 8408:2005 "Road traffic signs. Testing and performance of microprismatic retroreflective sheeting materials. Specification".

The sign prescribed for use with the advance sign vehicles is diagram 7402 using 300 mm wide arrows; see working drawing P7202 for design details. Working drawings for the design of the signs shown in the plans and other prescribed signs are available for download free of charge from the Department for Transport website: www.dft.gov.uk/roads/signs.

The MLC signs to diagrams 7402 and 7403 must be reflectorised in their entirety, including the yellow background in which the flashing amber lamps are installed. The material, when rated in accordance with BS 8408 "Testing and Performance of microprismatic retroreflective sheeting – Specification" shall have a performance index of not less than 3.0 for a V1 vehicle (passenger car), using angularity A1, luminance index B and a sign location correction factor of 1.0. It shall achieve this performance index rating for each of the distance ranges D1, D2 and D3. It is not necessary to provide sign lighting luminaires when signs are reflectorised in accordance with this specification (except in Northern Ireland). Care and maintenance of the sheeting material should be in accordance with the manufacturer’s guidelines. See also Section O4.3.

The sign to diagram 7403 may be used with the block vehicle, but a higher visibility light arrow alternative sign is recommended. This sign incorporates a flashing light arrow to supplement the message given by the "keep left/right" sign to diagram 610. The design and operation of the sign must have type approval and special signs authorisation. A description of this sign is given in Section O10.8. The light arrow sign shall not display any form of arrow when on a two-way single carriageway road and, other than at the scene of an incident, the light arrow sign shall not display any form of arrow when on a hard shoulder of a dual carriageway.

On the light arrow sign and the sign to diagram 7403, the arrow on the "keep left/right" sign to diagram 610 must be capable of indicating either "keep left" or "keep right". To avoid displaying an incorrect instruction during set up and removal of the MLC, the rotation of the arrow, or covering of the sign, should be carried out remotely from the driver’s cab, with a means for the driver to verify the arrow direction or state of the sign. 115