Citation

Fitzpatrick JT. Highw. Res. Board bull. 1960; 255: 138-145.

Copyright

(Copyright © 1960, National Research Council (U.S.A.), Highway Research Board)

DOI

unavailable

PMID

unavailable

Abstract

Consideration of the perception factor in night visibility has led to the joint evaluation of a recognized guidance concept and new reflective materials recently installed at a typical interchange. The retro-reflective treatment was specifically designed to distinguish by color, brightness, and position the location and design of exit and merging ramps. High intensity delineation was used for distant identification. For close approach, paved ramp surfaces were reflectorized for 200-300 ft. Yellow delineation and road surfaces for merging zones formed an integrated system denoting the required caution. For maximum contrast with its complement, and based on airfield practice for off-ramp guidance, a similar system in blue was used for exit areas and pertinent destination signs. Silver through lane delineation was retained with standard green guide signs. To provide adequate differential between green and blue signs, a distinctive blue sheeting was employed. Color and brightness requirements also established criteria for delineation and reflective road treatments. With upper beams, the reflective blue roadway initially provides 6 foot-lamberts luminance at 200 ft, the yellow 40 ft-1 compared to the untreated pavement returning 0.08 ft-1. The substantial increase in road surface luminance offers markedly improved contrast over the surround in both color and brightness. Integrated, color-keyed reflective systems thus afforded, suggest a method for effectively providing the motorist's visual cue and guidance needs night and day.