Abstract
Two related issues must be considered in assessing roadway visibility. Suitable criteria defining roadway visibility must be established, and practical measurement techniques must be developed to measure compliance against the criteria. This paper addresses both issues. It makes recommendations for setting roadway visibility criteria based upon a model of visual speed and accuracy, and for utilizing photometric image analysis systems to evaluate roadway applications. This paper appears in transportation research record no. 1247, Visibility criteria for signs, signals, and roadway lighting.