It is not within the scope of this paper to go further into legibility studies. However, it can be seen that considerable information on the various characteristics affecting highway sign legibility has been obtained by experimental research. Further systematic studies of such factors as brightness, stroke width, and spacing are desirable in order to measure more carefully their interaction. However, for practical purposes the legibility distances of the standard alphabet letters recommended by the national Joint Committee on Uniform Traffic control Devises are well known. The reports in this area are all too few and mostly unsystematic in their approach. They do indicate, however, the importance of attention gaining factor since signs may not be seen anywhere near the threshold legibility distance either. There is also great importance to attention gaining characteristics where signs must be seen in competition with other objects such as advertising signs or sir features of the environment.
Abstract