Arens Photometric and Visibility Laboratory
Manager: Carl K. Andersen (carl.andersen@fhwa.dot.gov)
PURPOSE
The Photometric and Visibility Laboratory (PVL) enables researchers
to evaluate the photometric and colorimetric properties of signing and marking
materials, including fluorescent materials. Studies of human-centered systems
related to visibility issues are also performed in this laboratory.
DESCRIPTION
The laboratory develops recommendations for the specification of materials, both
in photometric and colorimetric terms. The laboratory also evaluates
transport-related lighting and signing equipment, including automobile headlamps
(as they affect the visibility of signs and markings) and traffic control
devices (particularly the light-emitting diode and fiber-optic types).
Photometric calibration services are provided by the laboratory to ensure that
instruments are accurate, both for in-house work and for work conducted by
contractors.
MAJOR /UNIQUE COMPONENTS
- Gamma Scientific 940D Computerized Photometric Range System; a 15-meter photometric range that includes a three-axis goniometer for placement of samples and an Observation Angle Positioner for angular separation of the light source and photometer. The system is primarily used in the measurement of retroreflective materials, but may also be used for photometric measurement of small light sources, such as headlights and traffic control signal lights.
- Optronic Laboratory Type OL-754 double-monochromator spectroradiometer.
- Photo Research PR-650 array-type colorimeter.
- Photo Research Model 1980A Pritchard Photometer (luminance meter) with Cassegrain lens, with an effective aperture of 0.2 minutes of arc.
- Photo Research PR-880 Spot Photometer (luminance meter).
- Labsphere-type BFC-450 bispectral fluorescence colorimeter.
- Illuminance meters, used to provide validation measurements of laboratory instruments.
- NIST-calibrated luminous intensity standards, precision shunts, and voltmeters for calibration purposes.
- NIST-traceable Standard Calibration Source (luminance and color temperature).
ACCOMPLISHMENTS
PVL has conducted in-house studies and investigations in support of contract research studies, the development by the Operations Core Business Unit staff of the new edition of the Manual on Uniform Traffic Control Devices, and the work of other government agencies on
topics, including the measurement of the color characteristics of retroreflective materials for the revision of the 1979 Federal Highway Administration (FHWA) Color Tolerances, evaluation of pavement markings under automobile headlamps, photometric evaluation of a mobile sign retroreflectometer, evaluation of fluorescent signing materials and ultraviolet headlighting, and design of a universal, multipurpose, computer-controlled roadway lighting system for the Smart Road in Blacksburg, VA.
PARTNERSHIPS & CUSTOMERS
Our partners include other offices of FHWA, other Federal agencies (e.g., the National Highway Traffic Safety Administration, Federal Aviation Administration, National Parks Service, Consumer Product Safety Commission), State departments of transportation, Government contractors, professional/engineering organizations (e.g., ASTM, HITEC), and the manufacturers and users of signing and marking materials and light-emitting traffic control devices.
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