OBSTACLE VISIBILITY IN RURAL NIGHT DRIVING AS RELATED TO REFLECTIVE QUALITIES OF THE ROAD SURFACE

NIGHT DRIVING VISIBILITY DISTANCES WERE MEASURED IN A SERIES OF EXPERIMENTS. THE TYPE OF ROAD SURFACE WAS THE MAIN INDEPENDENT VARIABLE. TWO ROUGH AND TWO SMOOTH ROAD SURFACES WITH A LARGE VARIATION IN THEIR RETROREFLECTIVE QUALITIES, WERE USED. THESE REFLECTIVE QUALITIES WERE VARIED BY MEASURING VISIBILITY DISTANCE IN BOTH DRY AND WET ROAD SURFACE CONDITIONS. THE SIZE OF THE OBSTACLE USED WAS 0.4 BY 0.4 METRES AND THE LUMINANCE FACTOR WAS VARIED BETWEEN 3% AND 26%. VISIBILITY DISTANCES WERE DETERMINED IN THE FOLLOWING FULL SCALE SIMULATED DRIVING SITUATIONS: A) LOW BEAM WITHOUT OPPOSING LIGHT B) LOW BEAM OPPOSING LOW BEAM C) HIGH BEAM WITHOUT OPPOSING LIGHT. THE VISIBILITY DISTANCE IN THE DIFFERENT DRIVING SITUATION DEPENDS ON DIFFERENT FACTORS. IN MEETING SITUATIONS ON DRY ROADS THE VISIBILITY DISTANCE IS DIRECTLY DEPENDENT ON THE LUMINACE FACTOR OF THE OBSTACLE WHEREAS ON WET ROADS, THE ROUGHNESS OF THE ROAD IS MOST INFLUENT. IN SITUATIONS WITHOUT MEETING LIGHT THE VISIBILITY DISTANCE TO A DARK GREY OBSTACLE INCREASES WITH DECREASING RETROREFLECTION OF THE ROAD SURFACE. IN MEETING SITUATIONS A LOW DEGREE OF SPECULAR REFLECTION (LOW GLARE) OF THE ROAD SURFACE IS MORE IMPORTANT THAN A HIGH RETROREFLECTION (HIGH BRIGHTNESS).

• Corporate Authors:

  Uppsala University, Sweden

  Uppsala,   Sweden 
• Authors:
  • Elmers, G
  • Rumar, K
• Publication Date: 1973

Language

• English

Media Info

• Features: Figures; References; Tables;
• Pagination: 32 p.

Subject/Index Terms

• TRT Terms: Brightness; Contrast; Driving; Dryness; Glare; Hazards; Headlamps; Low beamed headlamps; Luminance; Moisture content; Night; Night visibility; Obstructions (Navigation); Opposing traffic; Pavements; Reflectivity; Retroreflection; Roughness; Rural highways; Sight distance; Surface course (Pavements); Surfacing; Texture; Visibility; Visibility distance; Wet weather
• Uncontrolled Terms: Dry conditions; Wet conditions; Wet pavements
• Old TRIS Terms: Retrodirective reflection
• ITRD Terms: 6794: Contrast (visual); 1340: Dipped headlight; 1855: Driving (veh); 1677: Glare; 1342: Headlamp; 525: Luminance; 615: Meeting traffic; 9052: Night; 5926: Reflectivity; 3053: Surface texture; 2972: Surfacing; 6783: Visibility; 6793: Visibility distance; 3015: Wet road
• Subject Areas: Highways; Pavements; Safety and Human Factors; I23: Properties of Road Surfaces; I83: Accidents and the Human Factor;

Filing Info

• Accession Number: 00080863
• Record Type: Publication
• Source Agency: Transport and Road Research Laboratory (TRRL)
• Report/Paper Numbers: No. 137 R&D Rpt.
• Files: ITRD, TRIS
• Created Date: Mar 26 1975 12:00AM