Description

Short technical description: Purpose: The Arens Photometric and Visibility Laboratory conducts evaluations of the photometric and colorimetric properties of traffic control devices, including signing and pavement marking materials and traffic signal lights, and supports human factors research used to establish the required levels that meet the visual needs of drivers. 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). Validation of field instruments used for measurement of traffic control devices can be performed by comparison with laboratory instruments. Laboratory Capabilities: In addition to basic photometric and colorimetric measurements, the Arens Photometric and Visibility Laboratory evaluates fluorescence and retroreflective properties of materials. Results of these evaluations support Federal guidelines issued in the Manual on Uniform Traffic Control Devices as well as the development of consensus standards promulgated by the American Society for Testing and Materials International. Unique features: Laboratory Equipment: Gamma Scientific 940D Computerized Photometric Range System; an auto–ranging gonio–photometer that includes a three–axis goniometer for placement of samples and an Observation Angle Positioner (OAP) for angular separation of the light source and photometer. The goniometer is mounted on a rail, allowing the distance between the goniometer and the OAP to be adjusted from 1 meter to approximately 30 meters. 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 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). Specified type of facility: Road, Hardware, and Driver Visibility

Keywords

driver visibility, road and hardware visibility

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