Application of the visibility level (VL) concept is extended to street lighting by means of the 1989 Adrian model. Keck put small target visibility (STV), also based on the Adrian model, into a street lighting application program with certain limitations (plane targets and VL average). An alternative is given in this paper in which solid targets, hemispherical and facing the driver, replace the plane targets, and VL (minimum) replaces VL (average). The concept has been applied to dry road surfaces as defined by the CIE (Commission Internationale de l'Eclairage) and is now extended to wet road surfaces. Specific designs based on Scandinavian and English practice are developed to provide guidance by using the VL (minimum) as a criterion. (Author/publisher)
Samenvatting