IES LM-68-00

This Lighting Measurements Guide provides guidance to transportation and illuminating engineers who need to test the photometric performance of traffic signals in situ. It is a revision of LM-68-95, developed by the IESNA in cooperation with the Institute of Transportation Engineers (ITE). This update includes a recently-developed method for field measurements of traffic signals using a luminance meter, as well as information about field testing self-luminous traffic control devices. Techniques are also described that are useful when photometrically testing traffic signals in a laboratory.