We have also considered the claims of plastics and laminated glass fibre both of which are as yet little used in the construction of traffic signs in this country. Although these materials are less easy to reflectorise than metal they do have the advantages of being light in weight, easily maintained and not subject to corrosion; also, because they can be made translucent, they can be used for the construction of internally illuminated signs. Provided that signs in these materials can meet the requirements of British Standard No. 873, particularly as regards weathering, we think there should be more widespread trials of these materials.
Tubular steel posts are in common use as supports for traffic signs on all purpose roads in this country. They combine strength with a relatively small cross section and they are easily cut to suit special requirements. These factors, coupled with their ease of handling and erection make them particularly suitable for the mounting of signs in urban areas, especially where space may be restricted.
On motorways concrete posts have been employed with success for the mounting of large advance direction signs, but concrete has hitherto been little used in this country to mount signs on all-purpose roads. On visits abroad we have observed with interest the use of concrete for supporting high-mounted signs and also the single pillar concrete mounting for low signs. We have consulted our sign making industry regarding the economic attractions of this material abroad and the extent to which they would be valid in this country. We see no reason to recommend any widespread change to the use of this material for sign supports in this country.
285. However carefully traffic signs are designed and sited much of their value will be lost if they are not well maintained.
The amount of maintenance required depends to a large extent on the materials used, and capital cost frequently has a bearing on the extent of subsequent maintenance. We recommend that the attention of responsible authorities should be drawn to the disadvantages of automatically accepting the lowest tender for the supply of traffic signs and that they should be reminded that higher first costs may well be justified by savings in maintenance costs.
286. The general standard of maintenance of signs and their lighting equipment leaves much to be desired. It is most important that signs should be regularly cleaned and painted . Low mounted direction signs are particularly liable to be obscured by dirt thrown up from the carriageway in wet weather. When more of these signs are low mounted, as we recommend, in order to be seen in dipped headlights, there must be increasing attention to keeping them clean. This may entail more staff and costs unless improved mechanical cleaning equipment can be produced.
287. Traffic signals and sign lighting equipment should both be checked by specialist staff to ensure that intensities do not fall below specifications; they should also be inspected regularly after dark to detect faulty lamps and equipment.
288. When waiting and loading restrictions are to a greater extent indicated by yellow markings at the edge of the carriageway, these markings will need constant inspection and renewal to ensure that they do not become obliterated.
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