provision, however, for an inscription defining the danger to be substituted for this symbol. We have already followed this course in our recommendations for the signs at, for example, figures 60 and 62. Nevertheless we can envisage circumstances in which this Protocol sign would be useful and we therefore recommend that it be adopted in the form shown in figure 69.
We consider the exclamation mark to be more arresting than the Protocol symbol. This sign should be supplemented by a plate as at figure 69a indicating the nature of the danger.
129. This sign, which takes the form of a circular cluster of reflecting studs, is mounted on a post between 2 feet 6 inches and 4 feet 6 inches above the level of the carriageway. It gives a useful indication of the line of the carriageway on bends or where the ground falls away beyond the verge and it can also be used to mark obstructions near the kerb. Red reflectors are used to mark the nearside edge of the carriageway and white reflectors the offside edge. We recommend the continued use of this sign but suggest that it should be permissible for it to have a rectangular shape of the same area in reflecting material. Where a post is specially provided for the sign it should be coloured in black and white horizontal bands.
It would be helpful if these signs were referred to as 'hazard markers' to avoid confusion between them and the much lower markers used on motorways and some other roads. The latter have proved to be very helpful to drivers , especially in fog, and we recommend that wider use be made of them particularly on Primary roads but trials will be necessary to determine the best design, appropriate siting and correct spacing.
130. Protocol informatory signs are basically rectangular. We consider them under two main headings-directional signs and others.
131. The purpose of directional signs is to enable drivers to find their way to their destination . There are three kinds:
(i) advance direction signs, which give a driver information as to his route before he reaches a road junction;
(ii) direction signs, which give route information at a junction; and
(iii) route confirmatory signs, which give confirmation after a junction as to the identity of the route.
132. Our present directional sign system derives basically from the Report of the 1933 Traffic Signs Committee who recommended inter alia, that map type advance direction signs should be introduced, with route numbers and place names displayed in panels; that route numbers should be placed above place names and that numbers should have a height three times greater than the letter height of the place names; lastly, that chequer symbols should be employed to show, where appropriate, that the route mentioned is reached indirectly.
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