Current published standards for vehicular and pedestrian traffic control signal heads which are issued by the Institute of Traffic Engineers (ITE) do not contain provisions for use of the more accurate instrumental test methods or for fully evaluating the chromaticity of the thermoplastic lens materials. The present standards are based upon the use of certified limit filters, for determination of chromaticity and transmittance. Certified limit filters are no longer available for purchase from the National Bureau of Standards. Procedures for the calibration of both limit and reference filters are contained in this report along with historical and spectral transmittance data on the limit glasses which were used as the basis of the present standards. The report proposes the instrumental measurement of chromaticity to be the specified test method, and that color 'calibration' filters of the material being tested be used to calibrate the colorimeter rather than limit filters. This report further proposes elimination of lens transmittance requirements to be replaced with luminous intensity requirements for each vehicular signal type and color and luminance requirements for pedestrian signals. Revisions are proposed for the ITE standards to accomplish these changes.
Development of Standards and Tests for Acceptance of Traffic Signal Lenses
1977
116 pages
Report
No indication
English
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