Toward adding visibility quality to the road lighting design computer programs

In this paper the visibility level (VL) formulation of Adrian and the visibility index (VI) formulation of Blackwell are examined to add the visibility quality to the road lighting design computer programs. The description of the visual critical object under tangible traffic conditions has been made for the VL and VI values can be calculated. Finally, a table representing the visibility levels together with the recommended values of road lighting parameter for the different road categories is arranged