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Photometric indicators of headlamp performance.

File Language:
English


Details

  • Creators:
    Sullivan, John M. ; Flannagan, Michael J.
  • Corporate Creators:
    University of Michigan. Transportation Research Institute
  • Subject/TRT Terms:
  • 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
  • Download URL:
    https://rosap.ntl.bts.gov/view/dot/16996/dot_16996_DS1.pdf
  • File Type:
    Filetype[PDF - 751.45 KB]
  • Collection(s):
    US Transportation Collection
  • Main Document Checksum:
    urn:sha256:d8e8fd6370b4ad62128a34ad0c8f2454f9d2ff7d631490bfb6670f14fddff2b5
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