4STACK TYPE ADVANCE DIRECTION SIGNS
GENERAL DESIGN CONSIDERATIONS
4.1 Stack type signs are intended for use only at simple junctions and should not indicate more than three directions as the sign would then become difficult to read. Where four or more directions are to be signed a map type sign should be used. Stack type signs may supplement map type signs (i.e. where there are two advance direction signs on the approach to a junction and the first is a map type sign, the second may be a stack type sign).
4.2 There is some flexibility in the design of a stack type sign and figure 11-7 illustrates alternative layouts for the same junction. By careful arrangement of the directional panels the overall size of the sign can be minimised. In some cases, however, the smallest sign may not necessarily be the clearest and therefore should not be the automatic choice for a particular location.
DESIGN OF A SIMPLE STACK TYPE SIGN
4.3 The simplest type of stack type sign is one that indicates a single route, as shown in figure 4-1. The legend tiles will normally be 2.5sw from the top border and 1.5sw from the bottom border, in accordance with the basic sign design rules (see figure 2-4). Where the vertical dimension of the arrow determines the height of the sign, the legend is positioned so that the gap to the top border is greater than the gap to the bottom border by 1 sw. The arrow is always centred vertically on the sign, with a minimum gap of 2.5sw to the top and bottom borders. Figure 4-2 shows the design of a sign with a legend panel. Both the arrow and the panel are centred vertically on the sign. Figure 4-3 shows how a stack type sign is designed to accommodate a single line legend with a patched route number. This follows design principles similar to those shown in figure 3-10.
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