The Adrian/CIE Visibility Model: A Visibility Level Calculator & Future Research

Diminished visibility in dim light degrades performance and safety on real-world tasks that depend on the timely detection of visual targets. The goals of this paper are to: 1. review factors that affect nighttime visibility, with an emphasis on driving, 2. provide the reader with online access to an automated modified Adrian/CIE visibility level (VL) calculator (VLC), and 3. suggest future research for enhancing the objective measurement of visibility. Recognizing that luminance contrast is the primary sensory determinant of nighttime visibility, several contrast-detection models have been proposed to quantify visibility in dim lighting. Of these, the Adrian (1989) model accounts for comparatively more of the important variables and has been the most widely accepted. The mathematical steps for calculating target VL in the modified Adrian/CIE model are presented and the VLC user interface is explained in step-by-step order. The VLC provides an easy-to-use tool for calculating target VL. Several additional factors that affect VL that are not currently included in the model provide important research opportunities for enhancing the measurement of target visibility in nighttime conditions. The VLC is an open-access application intended to foster the measurement of VL in professional practice and to foster research to advance the utility of the Adrian/CIE model.