TRB 2000 Human Factors Workshop
Photometry for Traffic Engineers

WORKSHOP TITLE
Photometry for Traffic Engineers

WORKSHOP ORGANIZERS
Frank Schieber, University of South Dakota
Susan Chrysler, 3M Traffic Control Materials

WORKSHOP DESCRIPTION
The quantification of effective light energy emitted or reflected from the roadway infrastructure is a critical skill required for many traffic engineering applications. Yet, light measurement from traffic control devices requires an appreciation of many problems and issues not typically addressed in general-purpose photometry texts or courses. This workshop will provide a tutorial introduction to principles of photometry tailored to the special needs of traffic engineers followed by hands-on demonstrations of the instruments and procedures necessary to accurately measure light from traffic signals, highway signs and roadway delineation treatments.

BIOGRAPHICAL STATEMENTS

Frank Schieber is professor of Human Factors and Engineering Psychology at the University of South Dakota. He has extensive consulting and research experience in the area of highway and vehicle human factors with an emphasis upon the visual problems of older drivers. He received his Ph.D. in Experimental Psychology from the University of Notre Dame.

Susan Chrysler is a Human Factors Specialist in the Visibility Research Group in the Traffic Control Materials Division Laboratory of the 3M Company in St. Paul, MN. She has conducted research in the areas of traffic sign legibility, aging vision, headlamp illumination patterns, and reading comprehension. She received her Ph.D. in Experimental Psychology from the University of Minnesota.

PRELIMINARY CAST OF PRESENTERS/TOPICS

Morning Tutorial Session

1. Photometry 101 (Frank Schieber)

Radiometry vs photometry; luminous intensity (headlamps in candelas); illuminance (street lighting in lux); luminance (signs; markings; etc in cd/meter-squared); psychophysics of contrast; visibility models.

2. Colorimetry (Dave Burns)

CIE Model (for dummies); CIE chromaticity coordinates; common measurement systems; CIE/MUTCD color specs; fluorescent colors (why they are a special case)

3. Retroreflectivity (Sue Chrysler)

The problem with headlights (angle of reflection = angle of incidence); history of retroreflective materials; measurement issues (geometry, etc.); luminance output as a function of operational viewing distance; {say something about FHWA min. retroreflectivity requirements if you like}

Afternoon Demonstrations

1. Simple (standard) photometric measurements of: luminous intensity; illuminance; luminance; demonstration of the "aperture" problem

2. Measurement and specification of chromaticity

3. Measurement of retroreflective materials.