Photometric indicators of headlamp performance.

Details

• Creators:
  Sullivan, John M. ; Flannagan, Michael J.
• Corporate Creators:
  University of Michigan. Transportation Research Institute
• Subject/TRT Terms:
  Automobiles--Lighting--Testing Headlamps Photometry
• Publication/ Report Number:
  UMTRI-2009-18
• Resource Type:
  Tech Report
• Geographical Coverage:
  Michigan
• Corporate Publisher:
  University of Michigan. Transportation Research Institute
• Abstract:
  The visibility of an object is largely determined by the relative contrast between the
  
  object and its background. Thus, it might be assumed that without consideration of
  
  environmental conditions surrounding a target illuminated by a headlamp, target visibility may
  
  not be accurately assessed. That is, methods that consider only illuminance characteristics of
  
  headlamps (e.g., distribution and intensity of light) may assess headlamp performance
  
  differently from methods that include roadway and viewing conditions in the appraisal.
  
  In this report, headlamp performance ratings are first generated using CHESS, a
  
  software application that determines visibility by simulating headlamp illumination, roadway,
  
  and target characteristics, using target contrast. The CHESS ratings were then compared with
  
  ratings obtained by two alternative illuminance-based ratings methods. The first method, the
  
  lux-area method, computes road area at or above an established lux threshold. The second
  
  method, the distant-light method, computes the average lux level within a predefined forward
  
  road area centered on the midline of the vehicle. Twenty-two tungsten halogen (TH) headlamps
  
  were evaluated using each method and their performance ratings were compared with the
  
  CHESS ratings. The simple illuminance-based measures were found to be closely correlated
  
  with the CHESS ratings. The distant-light method produced the highest correlations.
  
  
• Format:
  PDF
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha256:d8e8fd6370b4ad62128a34ad0c8f2454f9d2ff7d631490bfb6670f14fddff2b5
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/16996/dot_16996_DS1.pdf
• File Type:
  [PDF - 751.45 KB ]