AN INVESTIGATION OF HEADLIGHT GLARE AS RELATED TO LATERAL SEPARATION

REPORT COVERS STUDY OF HEADLIGHT GLARE IN 3 PARTS: COMPILATION OF CURRENT STATUS OF KNOWLEDGE, FIELD TESTS OF DISABILITY GLARE, AND FIELD TESTS OF DISCOMFORT GLARE. ALTHOUGH LIMITED IN SCOPE, THE STUDY SHOWED THAT THE 94-FOOT LATERAL SEPARATION PROVIDED THE MOST TOLERABLE LEVELS IF BOTH DISABILITY AND DISCOMFORT GLARE ARE CONSIDERED FOR A HIGH BEAM MEETING SITUATION. DISCOMFORT GLARE WAS THE CONTROLLED FACTOR. LOW BEAMS ON THE OTHER HAND PROVIDED COMFORTABLE SEEING UNDER ALL CONDITIONS, BUT RESTRICTED THE SEEING DISTANCES SUCH THAT NONE OF THE LOW REFLECTANCE TARGETS WAS VISIBLE AT A DISTANCE EXCEEDING THE SAFE STOPPING DISTANCE AT 40 MPH. HIGH REFLECTION TARGET COULD BE SEEN IN TIME TO STOP FROM 50 MPH AT LATERAL SEPARATION WIDER THAN 33 FEET. ALTHOUGH INCREASES IN LATERAL SEPARATION APPEARED MORE EFFECTIVE IN REDUCING DISABILITY GLARE THAN POLARIZED HEADLIGHTING, THE VALUE OF POLARIZED HEADLIGHTING FOR THE 6-FOOT LATERAL SEPARATION (TWO-LANE HIGHWAYS) CANNOT BE IGNORED. IN ALL BUT ONE CASE, POLARIZATION OF CURRENT HIGH BEAM HEADLAMPS PROVIDED INCREASED SEEING DISTANCE AT THIS SEPARATION. FURTHERMORE, 64 PERCENT OF 240 OBSERVATIONS INDICATED NO DISCOMFORT AND 30 PERCENT INDICATED LITTLE OR SOME DISCOMFORT. THE EFFECTIVENESS OF POLARIZATION IN TERMS OF DISABILITY AND DISCOMFORT GLARE IS EVIDENT. /BPR/

  • Corporate Authors:

    Illinois Department of Transportation

    Division of Highways, 2300 South Dirksen Parkway
    Springfield, IL  United States  62764

    University of Illinois, Urbana-Champaign

    Urbana, IL  United States  61801
  • Publication Date: 1967-6-19

Subject/Index Terms

Filing Info

  • Accession Number: 00219687
  • Record Type: Publication
  • Source Agency: Bureau of Public Roads /US
  • Report/Paper Numbers: Irh-87
  • Files: TRIS
  • Created Date: Oct 31 1994 12:00AM