FOG ACCIDENT PREVENTION STUDY: VISIBILITY OF COLORED LUMINOUS AREAS IN FOG

A SERIES OF SUBJECTIVE VISIBILITY TESTS, PERFORMED WITH LUMINOUS-AREA, RED-LIGHT SOURCES OF DIFFERENT SIZES IN ARTIFICIALLY GENERATED FOG, SHOW THAT IN DAYTIME FOG OF 50-FT VISUAL RANGE AND NIGHTTIME FOG OF 100-FT VISUAL RANGE, THERE WAS NO APPRECIABLE DIFFERENCE IN VISIBLILTY BETWEEN 2-IN. -DIAMETER AND 6-IN. -DIAMETER SOURCES OF EQUAL INTENSITIES. IN NIGHTTIME FOG OF 500-FT VISUAL RANGE, THE LARGER SOURCE WAS FOUND TO BE SOMEWHAT MORE VISIBLE THAN THE SMALLER ONE. ANOTHER SERIES OF SUBJECTIVE TESTS WERE PERFORMED UNDER VARIOUS VISIBILITY CONDITIONS TO DETERMINE THE VISUAL DETECTION CONTRASTS FOR RED, AMBER AND GREEN LUMINOUS AREA TARGETS VIEWED AGAINST CORRESPONDINGLY COLORED BACKGROUNDS. THE RESULTS SHOW THAT UNDER CLEAR-WEATHER CONDITIONS, DAYTIME OR NIGHTTIME, THERE WAS NO APPRECIABLE DIFFERENCE IN TARGETS-TO-BACKGROUND DETECTION CONTRASTS FOR THE THREE COLORS. IN FOG OF 100- 150-FT VISUAL RANGE, HOWEVER, FOR AMBER BEING INTERMEDIATE BETWEEN THE OTHER TWO COLORS. THESE DIFFERENCES WERE MORE PRONOUNCED IN DAYTIME FOG THAN IN NIGHTTIME FOG OF THE SAME DENSITY. /AUTHOR/

• Supplemental Notes:
  • Hpr, B-1-9, 4841-285
• Corporate Authors:

  University of California, Berkeley

  Institute of Transportation and Traffic Engineering
  Berkeley, CA  United States 

  California Division of Highways

  Bridge Department
  Sacramento, CA  United States  05914

  Bureau of Public Roads /US

  400 7th Street, SW
  Washington, DC  United States  20590
• Publication Date: 1969-4

Subject/Index Terms

• TRT Terms: Color; Daylight; Detection and identification; Detectors; Fog; Night visibility; Prevention; Safety; Testing; Traffic crashes; Visibility
• Subject Areas: Highways; Safety and Human Factors; Security and Emergencies;

Filing Info

• Accession Number: 00219724
• Record Type: Publication
• Source Agency: Bureau of Public Roads /US
• Files: TRIS
• Created Date: Sep 22 1994 12:00AM