J. Josefowicz, & D. Ha, LED Roadway Lighting Ltd. (2008) Vision & Exterior Lighting: Shining Some Light on Scotopic & Photopic Lumens in Roadway Conditions (*pdf). Halifax, NS. White paper reviewed and approved by Dr. Samuel M. Berman.
This white paper was written during my co-op work term for LED Roadway Lighting Ltd. in conjunction with Dr Jack Josefowicz and approved by lighting specialist Dr Samuel Berman.
The LED light spectrum was compared to
that of a conventional streetlight and the whiter spectrum of the LEDs
was proved to be more advantageous to nightvision as compared to the
warm orange glow of most conventional streetlights. It was written to
fill a gap in industrial knowledge on the interpretation of roadway
lighting standards as some LED companies were reducing their overall
light levels below standard lighting specifications to promote higher
energy efficiency levels, on the erroneous assumption that scotopic
lumens could be added to photopic lumens. Being the only paper
clarifying this fact and catering specifically to LED lighting, it
received quite a lot of attention in industry.
More detail can be found in the white paper, available for download or from the LED Roadway Lighting Ltd. website.