their over-use could eventually devalue their attention-attracting benefits. A less garish way of increasing a sign’s conspicuity may be simply to provide a standard sign of larger size. Not only will this be more noticeable than a smaller sign, but it will also improve legibility and hence reading distance, which a yellow backing board cannot.
14.22 Grey backing boards can be used to mount an assembly of signs. The minimum space between any sign and the edge of the backing board should be 50 mm. The minimum space between any two signs should be 4sw, or 100mm where the signs do not have worded legends (except supplementary plates, see figure 14-8). Where there are more than two signs, the spaces between each of the signs should be equal. Signs of different lengths should be centred horizontally on the backing board. Two flag type signs pointing in opposite directions should normally be mounted side by side, but where site constraints require that one sign should be mounted above the other, the assembly may look more balanced if the shorter sign is positioned slightly off-centre. The various elements of the signs shown in diagrams 2020, 2021, 2021.1, 2114.1, 2116, 2117, 2913.4 and the destination panels in diagrams 2908, 2908.1 and 2909 may have the borders touching, but not overlapping. An example of the use of a grey backing board is shown in figure 14-7. Directional signs should not be mounted on yellow backing boards. This is needlessly visually intrusive, and if increased conspicuity is necessary, this is more usefully achieved by using a larger X-height for the sign.
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