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Exit taper – a line of cones tapering into the kerb downstream of the working space. 

Lead-in taper – a line of cones tapering out from the kerb upstream of the working space.

Lighting-up time – the time between half an hour after sunset and half an hour before sunrise.

Longways clearance (L) – the distance between the end of the lead-in taper and the first traffic barrier placed across the lane.

Minor works – works with a planned duration of three days of less, excluding immediate or major works (see the Co-ordination Code of Practice for more details).

Mobile works – work carried out from a vehicle moving significantly more slowly than the general traffic.

Precautionary area – any part of any road, including side roads, that can be reached by following a route leading away from the centre of the crossing for a distance of 200 m or less.

Safety zone – additional space around the working space to ensure the safety of the workforce and highway users.

Short-duration static works – works carried out at one or more intermittent stops, each lasting less than 60 minutes (30 minutes in Scotland).

Sideways clearance (S) – the part of the safety zone between the working space and moving traffic.

Tapping rail – a rail at the base of pedestrian barriers used by visually impaired long-cane users.

Tramway path – the space needed by tramcars, which includes a safety zone around the tram.

TSRGD – Traffic Signs Regulations and General Directions, available at

Wig-wag signals – light signals (to diagram 3014) used to control traffic at level crossings, swing bridges, etc.