OBSTACLE VISIBILITY WITH EUROPEAN HALOGEN H4 AND AMERICAN SEALED BEAM HEADLIGHTS

IN A SERIES OF FIELD EXPERIMENTS NIGHT DRIVING VISIBILITY DISTANCES ARE MEASURED FOR EUROPEAN HALOGEN HEADLIGHTS (EH4) AND AMERICAN SEALED BEAM HEADLIGHTS (ASB). THE TESTS HAVE BEEN CARRIED OUT FOR VARIOUS RELEVANT TRAFFIC SITUATIONS. THE RESULTS SHOW THAT THE EUROPEAN MORE INTENSE HIGH BEAM GIVES A 15% LONGER VISIBILITY DISTANCE TO A GREY OBJECT, .4 M BROAD 1.0 M HIGH ON STRAIGHT ROADS WHILE IN SHARP CURVES THE DIFFERENCE IS NEGLIGIBLE. WITH LOW BEAM OPPOSING LOW BEAM IT WAS FOUND THAT THE DIFFERENCE IN LIGHT DISTRIBUTION (EH4: SHARP CUT OFF, ASB: DIFFUSE CUT OFF) GAVE THE FOLLOWING VISIBILITY RESULTS: 1. IT IS UNDER NORMAL CONDITIONS ALWAYS A CONSIDEABLE ADVANTAGE (30 - 40%) TO HAVE ASB AND A SLIGHT DISADVANTAGE TO MEET ASB (10%) COMPARED WITH EH4; 2. THE ASB ADVANTAGE IS LARGER THE HIGHER THE LUMINANCE FACTOR OF THE OBSTACLES; 3. UNDER CONDITIONS OF MISAIMED HEADLIGHTS IT IS ALWAYS A CONSIDERABLE ADVANTAGE TO HAVE ASB. 4. THE TWO SYSTEMS GIVE ROUGHLY EQUAL VISIBILITY IN SHARP CURVES WITH AN ADVANTAGE FOR ASB IN SHARP CURVES TO THE LEFT. 5. SUBJECTIVELY EH4 WAS ESTIMATED SUPERIOR TO ASB ALSO IN SITUATIONS WHERE THEY GIVE SHORTER VISIBILITY DISTANCES. A SPECIAL GLARE EVALUATION CARRIED OUT BY PEDESTRIANS AND OPPOSING DRIVERS CLEARLY SHOWS HIGHER PERCEIVED GLARE FOR ASB. BUT NO INDICATION OF REAL DISCOMFORT OR IRRITATION WAS OBTAINED. FINALLY THE INVESTIGATION DEMONSTRATES THAT LOW BEAM VEHICLE LIGHTING VISIBILITY IS FAR FROM ACCEPTABLE IN RELATION TO NORMAL SPEEDS IN NIGHT TIME DRIVING. STRONG EFFORTS SHOULD BE MADE IN INCREASING THE VISIBILITY DISTANCE FURTHER. POLARIZED HEADLIGHTS OFFER A GENERAL SOLUTION TO THE PROBLEM IN THE LONG RUN. BUT IN THE MEANTIME A BETTER MEETING LIGHT - THE AMERICAN SEALED BEAM OR A MODIFIED VERSION OF IT - WOULD CONSTITUTE A CLEAR IMPROVEMENT.

• Supplemental Notes:
  • 2 APP
• Corporate Authors:

  Uppsala University, Sweden

  Department of Psychology, Tradgardsgaten 20
  75220 Uppsala,   Sweden 
• Authors:
  • Rumar, K
  • Helmers, G
  • Thorell, M
• Publication Date: 1973

Media Info

• Features: Figures; References; Tables;
• Pagination: 22 p.
• Serial:
  • Issue Number: 133

Subject/Index Terms

• TRT Terms: Brightness; Glare; Halogens; Headlamps; High beamed headlamps; Low beamed headlamps; Night visibility; Pedestrians; Polarized light; Visibility
• Old TRIS Terms: High beamed headlights; Low beamed headlights
• Subject Areas: Highways; Pedestrians and Bicyclists; Safety and Human Factors;

Filing Info

• Accession Number: 00224312
• Record Type: Publication
• Files: TRIS, ATRI
• Created Date: Aug 20 1973 12:00AM