Design of the Signage and Traffic Management Scheme
Detailed design of the layout, including the choice of signs to be used, is required to provide clear communication with road users. Five communication principles for good signage and markings are:
- Conspicuous – the sign has to be seen. (e.g. placing a sign behind a tree or bridge pier is not acceptable).
- Clear – the size and color of the letters and symbols, need to be legible and of sufficient size that can be easily read at an appropriate distance.
- Comprehensible – the sign needs to be understood (e.g. too many words on the sign may prevent the whole message being read by an approaching motorist).
- Credible – the message conveyed by the sign has to be believable to drivers, otherwise they will tend to ignore it (e.g. a Carabao warning sign in a highly urbanized area would probably be ignored).
- Consistent – similar traffic situations should use standard signs that are consistent with the Manual. If signs have consistent colour, shape symbols and words, this will reduce driver reaction times, improve driver understanding and increase the level of safety.
The signs need to convey the appropriate message and be placed to provide sufficient advanced warning to give drivers adequate time to read the signs and react. The following sequence is required:
- Provide advanced warning e.g. “Roadwork Ahead” • Provide information e.g. “Lane Closed”
- Give instructions on action required e.g. “Keep Left”
- Guide drivers where to go e.g. “Traffic cones”
Confusion can occur by using excessive signs so this needs to be avoided. Use only the number of signs necessary. The signage layout and traffic management needs to ensure that there is no doubt in the drivers mind regarding the information given and the actions required.