Controlled-Environment Evaluation of Fluorescent Strong Yellow-Green Pedestrian-Crossing Sign Prototypes

Abstract

Fluorescent strong yellow-green (SYG) is one of the most unassigned colors in the Manual on Uniform Traffic Control Devices (MUTCD). FHWA has recently been considering the SYG color for nonmotorized application in the W11-2 series of signs in MUTCD. A number of field evaluation studies on the impact of these warning signs on conflicts and user preferences have been undertaken. A controlled-environment evaluation of the SYG pedestrian-crossing sign prototypes under five different natural light conditions is presented. Factors that contribute to different driver performance in response to microprismatic fluorescent SYG signs relative to the commonly used enclosed-bead yellow signs are identified. Target value and legibility distance of the prototypes in a simulated driving environment on a pool of test subjects are assessed. A factorial analysis of variance design was used to obtain unbiased estimates of these parameters. The general linear model was used iteratively to eliminate factors that did not affect the model significantly. It was found that SYG pedestrian-crossing prototypes had better performances in terms of their legibility distances than the enclosed-bead prototypes although the target value did not show any difference. The results indicate that use of fluorescent SYG signs is likely to increase driver awareness of warning signs.