Additional data is presented on seeing factor effectiveness ratings for roadway lighting. Such ratings provide an essential basis for highway engineering evaluation of traffic, economic, and human benefits. Field measurements for different roadway lighting systems are continuing, are significant, and should be reported for the guidance of highway engineers interested in improving night motor vehicle transportation. Preliminary tests show that about twice as much pavement brightness is required for equivalent l-m visibility when the target is dynamic (0.1- to 0.2-sec exposure) instead of static. This is based on ratings by eight observers. Measurements made with the new blackwell portable visual task evaluator are reported and compared with those obtained with the finch visibility meter. Experience gained at hendersonville using the first prototype model of this meter retarded measurements earlier this year. More extensive data are now available and are presented. /author/
Samenvatting