OPTICAL PROPERTIES OF THE ATMOSPHERE AND HIGHWAY LIGHTING IN FOG

THE LIGHT TRANSMISSION AND POLAR SCATTERING PROPERTIES OF NATURAL AND ARTIFICIAL FOGS HAVE BEEN MEASURED. SINCE POLARIZATION EFFECTS IN SCATTER ARE VERY LARGE, CONSIDERABLE EFFORT HAS BEEN DEVOTED TO OBTAINING COMPLETE POLARIZATION INFORMATION. THESE DATA WILL BE USED TO DESIGN AND EVALUATE IMPROVED LIGHTING SYSTEMS FOR USE ON THE HIGHWAY IN FOG. FOR EACH PROPOSED SYSTEM, THE LUMINANCES AND CONTRASTS OF OBJECTS AS SEEN THROUGH THE FOG CAN NOW BE COMPUTED. THE SCATTERING CURVES HAVE ALREADY SUGGESTED SOME IMPROVEMENTS WHICH MIGHT BE MADE, AND THESE HAVE BEEN VIEWED IN A 3:1 SCALE MODEL SIMULATOR AT THE PENNSYLVANIA STATE UNIVERSITY AND IN A 25:1 SIMULATOR AT THE UNIVERSITY OF MICHIGAN. THESE TESTS HAVE DEMONSTRATED THAT VISIBILITY IN FOG CAN BE IMPROVED BY CHANGING THE CANDLEPOWER DISTRIBUTION OF STREET LIGHTS TO AVOID FORWARD SCATTER, BY EMPLOYING VEHICLE FOG LIGHTS WHICH ARE MOUNTED AS FAR AS POSSIBLE AWAY FROM THE DRIVER'S LINE-OF-VISION, AND BY INCREASING THE CANDLEPOWER OF TAILLIGHTS. QUANTITATIVE INFORMATION ABOUT THE IMPROVEMENTS TO BE GAINED BY THESE AND OTHER CHANGES WILL BE OBTAINED IN AN IMPROVED SIMULATOR NOW UNDER CONSTRUCTION. /AUTHOR/

• Record URL:
  http://onlinepubs.trb.org/Onlinepubs/hrbbulletin/191/191-002.pdf
• Supplemental Notes:
  • No 191, pp 7-16, 9 FIG, 1 TAB, 4 REF Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved.
• Authors:
  • PRITCHARD, B S
  • Blackwell, H Richard
• Publication Date: 1958

Media Info

• Media Type: Digital/other
• Pagination: 10p
• Monograph Title: Night visibility, 1958
• Serial:
  • Highway Research Board Bulletin
  • Issue Number: 191
  • Publisher: Highway Research Board

Subject/Index Terms

• TRT Terms: Atmosphere; Brightness; Fog; Luminous intensity; Optical properties; Polarization; Simulation; Street lighting; Taillamps; Training simulators; Vehicle lighting; Visibility
• Uncontrolled Terms: Change
• Old TRIS Terms: Scatter diagrams
• Subject Areas: Highways; Safety and Human Factors;

Filing Info

• Accession Number: 00220268
• Record Type: Publication
• Files: TRIS, TRB
• Created Date: Aug 19 1994 12:00AM