13.20 The design of the centre panel is carried out by combining the elements shown in figure 13-9. The design details for combining these elements are shown in figure 13-10. Where there are three or more lanes on the approach to the lane change, the stems at the base of the arrows should, wherever possible, be equally spaced with a minimum dimension of 400 mm centre to centre. The minimum dimension from the centre line of the arrow shaft to any border, central reservation symbol, red block or hard shoulder symbol is 200 mm.
13.21 Diagrams 7230 to 7239 inclusive show lane changes within the same carriageway (i.e. not involving contra-flow). The design principles are the same as those for the contra-flow signs described in paras 13.19 and 13.20 except that the central reservation symbol is not used.
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