DOMINANT CONTRAST AND VERTICAL ILLUMINANCE FOR PEDESTRIAN ILLUMINATION

摘要

Characterizing the night time visibility of pedestrians is a complex matter. Whereas most studies found in the literature relate visibility to contrast, street lighting design standards use vertical illuminance 1.5 m above ground as a design target. The objective of this manuscript is to examine dominant contrast and vertical illuminance as metrics for pedestrian illumination. A computer simulation was made to find whether vertical illuminance values at various heights correlate with dominant contrast. A procedure to find dominant contrast experimentally as well as using computer simulation is shown. A mathematical model to find dominant contrast index (DCI) is proposed.