Details:

Creators:
Sullivan, John M. ; Flannagan, Michael J.
Sullivan, John M. ; Flannagan, Michael J. Less -
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:

Supporting Files

• No Additional Files

More +