A PRESCRIPTION FOR ROAD WAY LIGHTING

THE RESEARCH REPORTED WAS DIRECTED TOWARD APPLYING THE CIE METHODS (CIE REPORT NO. 19) TO ROADWAY TASKS. AN ASSESSMENT WAS MADE OF THE VISIBILITY OF REALISTIC TARGETS IN DIFFERENT LOCATIONS ON A SIMULATED 8-LANE URBAN FREEWAY ILLUMINATED BY REALISTIC LUMINAIRES AT REALISTIC SPACINGS AND MOUNTING HEIGHTS, AS WELL AS BY A SYSTEM PROVIDING GENERALLY UNIFORM ILLUMINATION. THE RELEVANT INFORMATION CRITERION WAS DEFINED AS THE VISIBILITY OF THE TARGET THAT ENABLED AN OBSERVER TO "JUST BARELY DISCERN SOMETHING ON THE ROADWAY THAT SHOULD BE HEEDED." FROM THIS VALUE, THE EQUIVALENT CONTRAST (C) WAS DETERMINED. THE VALUES OF C WERE IN TURN USED TO DETERMINE THE VISIBILITY LEVEL (VL). TO TAKE INTO ACCOUNT THE EFFECTS OF SPATIAL PATTERNS (NONUNIFORMITIES), THE EFFECTIVE VISIBILITY LEVEL (EFVL) HAD TO BE DETERMINED. THE TWO FACTORS INVOLVED IN DETERMINING EFVL WERE THE DISABILITY GLARE FACTOR AND THE TRANSIENT ADAPTATION FACTOR, BOTH DESCRIBED IN DETAIL IN CIE REPORT NO. 19. IT SHOULD BE NOTED THAT EFVL VALUES WERE BASED ON AVERAGED REFERENCE DATA OBTAINED FROM 20 TO 30 YEAR -OLDS. THE EFVL VALUES OBTAINED FOR AN OLDER AGE GROUP WERE HIGHER. FUTURE RESEARCH WILL BE DIRECTED TOWARD STUDYING DIFFERENT ACTUAL VISUAL TASKS ON THE ROADWAY IN TERMS OF EFVL. FOR EXAMPLE, AN INVESTIGATION WILL BE CONDUCTED ON DETECTION DISTANCES FOR A STANDARD MULTIDIMENSIONAL TARGET AT DIFFERENT EFVL.

• Authors:
  • Blackwell, O M
• Publication Date: 1974-2

Media Info

• Features: Figures; References;
• Pagination: p. 38-41
• Serial:
  • Lighting Design and Application
  • Volume: 4
  • Issue Number: 2
  • Publisher: Illuminating Engineering Society

Subject/Index Terms

• TRT Terms: Glare; Shape; Street lighting; Visibility; Visual perception
• Old TRIS Terms: Shape factor
• Subject Areas: Highways; Safety and Human Factors;

Filing Info

• Accession Number: 00222382
• Record Type: Publication
• Files: TRIS
• Created Date: Mar 23 1974 12:00AM