O4.7.4 Care shall be taken to ensure that any lights are not misleading to rail, water or air traffic. In case of doubt the railway, harbour, port, river or airfield authority should be consulted.
O4.7.5 Lights using flammable substances, e.g. paraffin, should not be used.
O4.7.6 Warning lights must conform to the National Annex to BS EN 12352:2006. The external surface of the warning light body visible to road users shall be coloured lemon, colour reference no. 355, or golden yellow, colour reference no. 356 of BS 381C:1996, and the lights must also comply with the mounting height requirements of regulation 55(2) (in Northern Ireland, regulation 44(2)).
O4.7.7 Warning lights must show an amber light and may be placed at regular intervals along the line of an obstruction. However, when a vehicle restraint barrier is used, coloured reflectors should be placed at 18 m intervals along the side of the barrier in lieu of warning lights. Such reflectors must conform to diagram 560 or 561 in terms of their dimensions as well as their colour (red on the near side, amber on the off side of a dual carriageway or on a one-way road). Rectangular reflectors must be at least 35 mm wide, with a minimum area of 45 square centimetres, and circular reflectors must be at least 75 mm in diameter. Reflectors shall be cleaned frequently in order to maintain their effectiveness.
O4.7.8 Under normal circumstances, lights should be installed on stands or cones, and not at road level. The height of the centre of the lens of each light shall not exceed 1500 mm above the road surface where the speed limit is 40 mph or less, or 1200 mm where the speed limit is more than 40 mph.
O4.7.9 If there is any possibility of the lights masking the retroreflective cone sleeves then the lights should be placed on separate stands or cones midway between traffic cones.
O4.7.10 Lights should be switched on in a place of safety before being put into position.
O4.7.11 Reflectorised cones and markers should be used as an addition to, and not instead of, lights. Lights showing a steady light may be used on any road with or without street lighting. Alternatively, where lights are used within 50 m of an illuminated street light on a road with a speed limit of 40 mph or less, lights flashing at 55-150 flashes per minute may be used. Flashing warning lights must not be used on an unlit road unless specifically authorised.
O4.7.12 During the hours of darkness, any barriers to diagram 7105 provided to delineate the edge of the works may be illuminated by a means of either internal or external lighting. If not illuminated then they must be reflectorised in accordance with regulation 19. They may be marked by warning lights showing an amber light. See paragraph O4.7.6 for details.
O4.7.13 Care should be taken to ensure that the intervals at which bulbs and batteries are changed, and the type of replacement used, are in accordance with the manufacturer’s specification.
O4.7.14 High intensity flashing warning lights (with a peak intensity in excess of 100 candelas) showing an intermittent light are prescribed by the Regulations. They are used only to draw attention to the hazard existing at a particular site and they warn drivers to take special care. These flashing warning lights may be used only in combination with prescribed traffic signs and not as a means of delineating the works. These high intensity flashing lights are defined as warning light types WL5 and WL6 in the National Annex to BS EN 12352:2006 "Traffic control equipment. Warning and safety light devices".
O4.7.15 High intensity flashing warning lights of the uni-directional type may be used to supplement signs indicating road works, or the beginning of a temporary traffic diversion. They may also be used in association with police or weather condition signs to warn drivers to take special care. Excessive use of these lights on any one site will reduce their effectiveness and care should be taken to use them only to draw attention to signs indicating particularly hazardous situations. It should be noted that several unsynchronised flashing warning
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