Page:UK Traffic Signs Manual - Chapter 5 Road Markings. 2003 (Sixth Impression 2009).pdf/95

 The length of the section of controlled area from the Give Way or Stop line to the terminal line inclusive (the marked controlled area, L in para 15.18) equals NX + (N+1)150 + Y + Z, where N = the number of zig-zag lines, X = the longitudinal limit of each mark (see figure 15-3), Y = the width of the Give Way or Stop line and Z = the width of the terminal line (all dimensions in millimetres). For a 2 m mark, X = 1.979 m, and the length L for eight 2 m marks is 17.585 m. Where a longer approach marking is required, e.g. where visibility is poor or the speed of traffic is high, the number of marks may be increased up to a maximum of 18. The aim should be to lay at least the standard pattern of eight 2 m marks on both sides of the crossing. Where site constraints prevent this, the length of the zig-zag marks may be varied to a minimum of 1 m and the number of marks reduced to a minimum of two. Zig-zag marks shorter than 2 m should be used only to indicate a controlled area of fewer than eight marks. Even then marks as near as possible to the maximum 2 m length should be provided, using a smaller number if necessary; each mark in each zig-zag line must be substantially the same length as the other marks in the same line.

For controlled area lengths between 2.750 m and 17.585 m, the appropriate number of zig-zag marks should be determined from table 15-1. The longitudinal limit of each mark (X in figure 15-3) is obtained from the formula X = $L - 350 - Y - 150 N⁄N$ where L = the overall length available for marking, Y = the width of the Give Way or Stop line and N = the number of marks required from table 15-1 (all dimensions in millimetres).

Crossings on major roads should be located away from conflict points at uncontrolled junctions. The controlled area may extend across the mouth of a side road but it should never stop between the two projected kerb lines of the minor road. If this would otherwise occur, the zig-zag lines should be extended to the projection of the far kerb line of the side road.

Crossings on minor roads close to junctions will tend to restrict the layout of the controlled area markings. To preserve the effectiveness of a junction Give Way or Stop line, the terminal line of the zig-zag markings should not normally be less than 1 m from it. This distance may be reduced to 500 mm if necessary to enable the minimum pattern of markings to be laid. The controlled area should never extend beyond the nearer kerb line of the major road. It should be the aim to provide room for at least one vehicle turning into the minor road to wait at the crossing without obstructing traffic on the major road. More vehicles should be accommodated if there are large numbers turning. If signalled pedestrian crossings are sited too close to junctions, drivers might mistake a vehicular green signal for a priority signal over traffic on the major road.

Where part of a lay-by lies within the controlled area, the zig-zag markings should be laid along the edge of the main carriageway. However, the restrictions extend to the back of the lay-by.

Normally all zig-zag lines in a pattern should comprise the same number of marks. However, the Pedestrian Crossings Regulations allow for an exception to this rule to provide maximum coverage of the controlled area where the distance available for the marks on each side of the carriageway is unequal. 93