13.17 The length of the vertical arrow is generally 480 mm (see figure 13-6). However, when the sign incorporates diagram 7287 (lane closed), the arrow length is increased to 720 mm,' the total length of diagram 7287 (stem plus red bar) is 420mm (see figure 13-7). Where a sign to diagram 7201 is manufactured so that the arrow head can be changed to a red bar, all arrows should have a length of 720 mm whether or not the red bar is displayed. This type of sign is likely to be used where a closed lane is opened to traffic during peak hours. As the sign to diagram 7201.1 does not use the red bar symbol, a flap type variable message sign, with a reduced number of arrows, could be used where a lane is closed for part of the day.
13.18 The length of the white contra-flow arrow (diagram 7288) will normally be 720mm, including the black edge. Figure 13-8 shows how this arrow is placed alongside an upward pointing arrow.
DESIGN OF SIGNS SHOWING LANE CHANGES
13.19 Diagrams 7210 to 7218 inclusive show lane changes which occur in contra-flow situations. The central reservation is represented by the solid black symbol and the areas of closed carriageway by red blocks. Where traffic is directed onto a hard shoulder, a thin black line is used to denote the division between the hard shoulder and the normal running lane. Figure 13-9 shows the basic design details for the curved arrows, red blocks, central reservation symbol and hard shoulder demarcation line. The table in figure 13-4 is applicable to these signs when determining the position of the arrows. The vertical edges of the central reservation symbol, red block and hard shoulder line should be treated in the same way as the sign border when using the table. A horizontal bar may be used where two or more unsegregated lanes lead to the same named destination or route (see diagram 7212). The design of this bar is the same as for diagram 7201 (see figure 13-6). The 150mm radius on the red block is applied only where there is a curved arrow immediately adjacent. Where there is a hard shoulder line between the red block and the arrow, a non-radiused corner is used. A non-radiused corner is also used in diagram 7240, where the bifurcation arrow does not have a fillet (see figure 13-18).
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