Some Factors Influencing the Night Visibility of Roadway Obstacles

Interest in the night-visibility of the roadway scene is wide spread and has been the subject of numerous research efforts of which this paper is only a small segment. We at the University of California have been working in various phases of this field continuously on an organized basis since 1919. This report covers one phase having to do with street lighting and its evaluation in terms of the visibility of objects under specified conditions of observation. The work included in this paper has been partially sponsored by the Illuminating Engineering Research Institute in a grant made to the University of California in 1952. This paper is a summary of the accomplishments made during the period of the grant (August 1952 to August 1955) and of the concurrent work done by graduate students with University support.