essential in the interests of smooth and safe traffic flow; with downward-pointing arrows associated with the relative place-names and route-numbers, it is the only really sound method of indicating the appropriate traffic lanes, and because of its size and position it should be visible from a considerable distance. It would also be out of the range of mud splash . We consider that its disruptive effect on the landscape can be kept to a minimum by the careful design both of the sign itself and of its supporting structure; the sign we recommend is illustrated in figure 35.
106. We recommend that the third sign should also be an overhead sign and should be sited just beyond the point of bifurcation of the two arms of the junction. In this position it would fulfill the same function as the final advance direction sign and supplementary exit sign at ordinary junctions along the motorway.
107. We recognise that the recommendations we have made in the two preceding paragraphs for overhead signs may encounter opposition in some quarters, and in general we see no reason why these signs should be erected before traffic volumes have reached the size at which the maximum visibility they offer becomes necessary. We think that in the meantime roadside signs more closely comparable with the half-mile and final advance direction signs for ordinary intermediate junctions will probably be sufficient. Because of the even greater need for correct lane discipline at these junctions of two motorways, however, and because both arms of the junctions are of equal importance, the half-mile and final advance direction signs we recommend here (figure 39) differ in several respects from their counterparts for other intermediate junctions. To save space we have dispensed with the junction symbol altogether and adopted the American device of 'stacking' the place- names and route-numbers with an arrow alongside each word-group pointing in the appropriate direction. (There is already provision for signs of this basic type in the Traffic Signs Regulations, 1957.) We have added the instruction 'Get in lane'; we do not, however, favour the inclusion of 'm' in the half-mile sign, because it would add to the height of an already tall sign, because an indication of distance has already been given on the mile sign (paragraph 103), and because if the instruction 'Get in lane' is followed it is not strictly necessary. The half-mile and final signs will thus be identical; the final sign should be sited at the point where the motorway begins to widen to form the two arms of the junction. We do not think that these signs are so clear as either the overhead signs we have recommended in paragraphs 105 and 106 or the roadside signs we have recommended in paragraphs 86-88 for ordinary intermediate junctions, and we do not think they should be used in place of those signs unless there are very sound reasons (e.g. small traffic volumes at junctions of two motorways, insufficient space combined with small traffic volumes at other junctions) for this course.
108. It so happens that at one of the forks in the first section of the London-Yorkshire Motorway there is a bridge carrying an all-purpose road over the motorway at almost precisely the point where the roadside final direction sign would be sited, and we consider that the opportunity should be taken to place a direction sign on the parapet of this bridge in order to be able immediately to assess the effectiveness of overhead signs in this country. We understand that while the Royal Fine Art Commission would not object to this if it was considered
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