In the first phase of this project, information will be gathered to provide a basis for the design of the luminaire to be developed later in the project. The information gathered will include data on systems being specified in Europe and on human performance measurements that have been made under the relatively low light level conditions typical of outdoor lighting.

Recent work by the Lighting Research Center (LRC) and others has shown that at a fixed photopic light level, off-axis reaction times are significantly shorter with scotopically rich sources, such as metal halide sources, than with scotopically poor sources, such as low-pressure or high pressure sodium. Work at a number of institutions, including LBNL, has also shown that the perception of brightness at a fixed photopic light level is also higher with scotopically rich sources.

Recent work at LRC has examined the issues of people's perception of security and brightness under these different types of lighting, and has provided some confirmation of the more theoretical results on reaction time and brightness perception. LRC has also studied search times for colored objects under the different lighting systems. This issue relates both to night vision versus day vision (scotopic versus photopic), and to the color rendering ability of the sources.

White sources, such as metal halide lamps, have higher color rendering ability and are scotopically richer than yellow sources, such as HPS or LPS. Combining the results of the studies on reaction time, perception of security and brightness, and search time for colored objects suggests the opportunity for scotopically rich sources to provide greater benefit for outdoor lighting.