to that of the capital letters on the sign. The survey referred to earlier confirmed that route numbers are understood and relied upon by a considerable proportion of drivers and we believe that a distinctive yellow colouring will enable them to be picked out more easily. In the past, route numbers have been larger than the letters of place names. We believe that this is unnecessary and we recommend that the numbers and letters be the same height as the capitals of place names so that the whole message of a sign is legible at the same distance. This reduction in the size of route numbers relative to place names will save a certain amount of space on the sign, with reduction in costs and gain in amenity.
144. In order to give a driver as much help as possible in selecting his route, we recommend that the route symbol used should indicate the essential features of the lay-out of the junction or roundabout. We recommend that the relative importance of the intersecting routes should be indicated by difference in thickness of the arms of the symbol. Primary routes should be shown by a route symbol of 6 stroke-widths, class III and unclassified roads by one of 2½ stroke-widths, and all other classified roads by one of 4 stroke-widths. A stroke-width is the width of a vertical stroke in a capital letter of the appropriate alphabet.
145. The use of the chequer symbol to denote routes which may be joined indirectly is clearly not possible in its present form on signs without panels. In considering whether such a symbol is still needed we asked the Social Survey to investigate the extent to which its meaning is understood. They reported that the majority of drivers have some understanding of and therefore derive some help from the chequer symbols though only a small proportion fully understand its meaning. This led us to the conclusion that it is of sufficient usefulness to justify its retention in some form.
After a number of experiments we concluded that destinations not lying on the numbered route indicated first on the advance direction sign should be distinguished by having brackets round the route number. These should be in yellow on green background signs and black when the background is white, so that they are of the same colour as the route number. Brackets should also be used where appropriate on other directional signs.
146. We have considered the criteria to be adopted in determining what place names should be included on directional signs and recommend that on Primary routes they should normally include only the next place of traffic importance since on these high speed roads it is essential to reduce the legend on a sign to the minimum. Exceptions will be necessary but should be made sparingly. A decision as to which places should rank as places of traffic importance should we think, rest with the Departments concerned in consultation with local authorities. This could be done at the same time as the selection of Primary routes and should lead to the establishment of a national network of Primary routes together with uniformity in the selection of place names.
On directional signs on other than Primary routes it will be less practicable and desirable to confine place names to places of traffic importance and on
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