SIDE LIGHTS AND LOW-BEAM HEADLIGHTS IN BUILT-UP AREAS

WITH WELL LIGHTED STREETS, LOW-BEAM HEADLIGHTS MAKE NO NOTICEABLE CONTRIBUTION TO PERCEPTIBILITY OF OBJECTS. WITH POORLY LIGHTED STREETS, LOW-BEAM HEADLIGHTS MAKE A POSITIVE CONTRIBUTION WITHOUT LEADING TO AN ADEQUATE PERCEPTIBILITY LEVEL FOR OBJECTS OF WHICH SMALL DETAILS HAVE TO BE OBSERVED. CYCLISTS AND PEDESTRIANS ARE SUCH OBJECTS. SIDE LIGHTS MAKE A NEGLIGIBLE CONTRIBUTION TO THIS. GLARE CAUSED BY APPROACHING CARS' LOW-BEAM HEADLIGHTS IS UNACCEPTABLE WITH ALL PREVAILING STANDARDS OF STREET LIGHTING, ESPECIALLY IF THERE ARE A LARGE NUMBER OF APPROACHING VEHICLES. SIDE LIGHTS HARDLY EVER CAUSE GLARE, BUT IN MANY CASES ARE NOT CONSPICUOUS ENOUGH. IF THE QUALITY OF STREET LIGHTING IS BETTER, MORE MOTORISTS VOLUNTARILY USE SIDE LIGHTS. THE INCREASE FROM ABOUT 35% TO ABOUT 80% LOW-BEAMED HEADLIGHTS DRIVERS IN THE BUILT-UP AREA OF UTRECHT DURING THE EXPERIMENTS HAD NO DEMONSTRABLE EFFECT ON THE TOTAL NUMBER OF TRAFFIC ACCIDENTS. NOR WERE ACCIDENTS HAZARDS IN THE DARK (THE DAYTIME/NIGHT-TIME RATIO) SIGNIFICANTLY CHANGED. THE SIMULTANEOUS USE OF SIDE LIGHTS AND LOW-BEAM HEADLIGHTS IS MISLEADING AND CONFUSING AND MAY BE A MAJOR SOURCE OF TRAFFIC ACCIDENTS IN THE DARK. IN VIEW OF THE RESULTS GIVEN ABOVE, THE ACTUAL PERCENTAGE OF LOW-BEAM HEADLIGHTS AND SIDE LIGHTS APPARENTLY HAS LITTLE EFFECT. THE LOW-BEAM HEAD-LIGHTS STANDARDISED IN MOST WEST EUROPEAN COUNTRIES (THE E LAMPS) ARE IN GOOD AGREEMENT, THOUGH THERE MAY BE CONSIDERABLE DIFFERENCES DUE TO MAL-ADJUSTMENT AND OBSOLENCENCE. THERE ARE, HOWEVER, BIG DIFFERENCES BETWEEN CAR SIDE LIGHTS. MANY ARE NOT CONSPICUOUS ENOUGH. THIS IS CONCLUDED, INTER ALIA, FROM THE DISPROPORTIONATELY SMALL NUMBER OF CASES INVOLVING LOW-BEAMED HEADLIGHTS DRIVERS AND PEDESTRIANS. EVEN A LOW INTENSITY OF SIDE LIGHTS SUFFICES FOR DETECTABILITY OF A SINGLE CAR UNDER LABORATORY CONDITIONS. INTERACTIONS BETWEEN SIDE-LIGHT DRIVERS AND PEDESTRIANS ARE THEREFORE ATTRIBUTABLE ESPECIALLY TO THE EXISTENCE OF DISTRACTING LIGHT SOURCES, FOR INSTANCE OTHER VEHICLES WITH HIGH INTENSITY LIGHTING. THE BEHAVIOR OF PEDESTRIANS CROSSING ROADS (EXPRESSED AS DESIRABLE CROSSING TIME AND FREQUENCY OF ERRONEOUS DECISIONS) IS NOT MEASURABLY DEPENDENT UPON THE INTENSITY OF THE CAR'S LIGHTS UNDER LABORATORY CONDITIONS WITH A SINGLE CAR APPROACHING ALONG AN OTHERWISE CLEAR ROAD. NOR DOES IT DEPEND UPON THE AVERAGE STANDARD OF STREET LIGHTING. FAULTY DECISIONS IN PRACTICE--ESPECIALLY WRONGLY CROSSING WHEN A XAR WITH SIDE LIGHTS IS APPROACHING--MUST THEREFORE BE THE CONSEQUENCE OF DISTURBING INFLUENCES, SUCH AS CARS WITH HIGH-INTENSITY LIGHTS. THE RESEARCH HAS INDICATED THAT BOTH LOW-BEAMED HEADLIGHTS AND SIDE LIGHTS HAVE CERTAIN DRAW-BACKS. IT IS ADVISABLE TO SEEK A LIGHTING SYSTEM FOR THE FRONT OF MOTOR VEHICLES WHICH LACKS THESE DRAWBACKS BUT PRESERVES THE ADVANTAGES. THIS CAN, FOR EXAMPLE, BE ACHIEVED WITH A LIGHT OF AN INTENSITY BETWEEN THE PRESENT LOW-BEAMED HEADLIGHTS AND SIDE LIGHTS, GUARANTEEING ADEQUATE CONSPICUOUSNESS WITH AN ACCEPTABLE DEGREE OF GLARE. THE USE OF SUCH 'NEW STYLE SIDE LIGHTS' HOWEVER, IMPLIES THAT THE PUBLIC LIGHTING MUST ALSO BE TAKEN INTO ACCOUNT. ALTERNATIVES SHOULD BE INVESTIGATED. /SRIS/

• Supplemental Notes:
  • 69 Pp, 23 FIG, 13 TAB, 24 REF
• Corporate Authors:

  Institute for Road Safety Research, SWOV

  Bezuidenhoutseweg 62
  The Hague,   Netherlands  2594 AW
• Authors:
  • SCHREUDER, D A
• Publication Date: 1968

Subject/Index Terms

• TRT Terms: Bicycles; Low beamed headlamps; Motorcycles; Pedestrians; Street lighting; Vehicle lighting
• Old TRIS Terms: Low beamed headlights
• Subject Areas: Highways; Pedestrians and Bicyclists; Safety and Human Factors;

Filing Info

• Accession Number: 00220895
• Record Type: Publication
• Source Agency: Nat Safety Council Safety Res Info Serv
• Files: TRIS
• Created Date: Nov 3 1970 12:00AM