118. We have asked ourselves what action a driver is expected to take when he sees this sign. In cases where general slight subsidence is already in progress the road surface will presumably be uneven. The appropriate warning for this seems to us to be the sign for Uneven road (figure 47), supplemented, if appropriate, by a plate giving the distance over which unevenness is to be expected (figure 70).
In places where there is material danger of the road subsiding it should presumably be closed to traffic but if the danger exists only as a remote possibility we do not consider that a warning sign would serve any useful purpose. We do not overlook the relatively wider danger of road subsidence in mining areas but we hope that measures can be taken other than the vague and alarming traffic sign at present prescribed .
119. We see no need for this sign and recommend instead use of the temporary sign at figure 137. It should be used either when there is an obstruction or when there is simply a rough or unfirm surface requiring reduced speed.
120. We have set out in paragraphs 192 to 198 our suggestions for a single and homogenous system of warning devices for road works.
121. Our Regulations do not prescribe a sign to indicate to drivers that they are approaching old people's homes or homes for the blind or otherwise disabled, nor is there a Protocol sign for this purpose. But requests are frequently made for signs of this type and we have considered them.
Experience shows that where a sign is erected to draw attention to conditions which are not constant, it is soon likely to be ignored. The occupants of these homes do not cross the road at any particular times of day and more often than not they do so singly, as other pedestrians would. We think that the elderly and infirm might find themselves in greater danger if they put their faith in the protection of signs than if they depended upon their own caution. We there fore recommend against the introduction of signs for old people's homes and similar institutions where crossing is spasmodic.
122. With the extended use of bare overhead conductor wires in railway electrification schemes, the number of places where live wires cross roads is increasing. Safety gauges with warning bells are sometimes provided over these roads to warn drivers of vehicles with high loads, but roadside warning signs are not at present prescribed in the Regulations and, since in this country prohibitory Orders do not normally specify a vehicle height limit, the prohibitory height limitation Protocol sign cannot be used. In view of the danger we think that roadside warning signs are very necessary and that the same sign should give warning of the presence of a gauge where this exists. There is no Protocol equivalent and we therefore recommend that the sign at figure 65 be erected
at and in advance of railway level crossings where there are overhead live wires.
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