Field Evaluation of Light Performance for New Light Sources in Roadway Lighting Applications

Indiana Department of Transportation (INDOT) is getting a lot of interest from vendors pushing the new light sources such as light emitting diode (LED), induction, and plasma for roadway lighting applications. Before adopting the new lighting technologies, INDOT intended to determine if the new lighting technologies meet required light performance and if they are cost effective, particularly with the existing lighting poles. Moreover, it is necessary for INDOT to establish standardized guidelines for evaluating the new lighting technologies prior to the formal adoption. To address these issues and gather first hand data, INDOT initiated a study to evaluate the total performance of these new lighting technologies. This paper presents the field evaluation of light performance with both conventional and high mast roadway lightings. Several luminaires, including LED, plasma and induction luminaires were selected to replace the existing high pressure sodium (HPS) lamps in both conventional and high mast lightings. Illuminance measurements were made over on both the existing and new light sources to identify light distributions. Light performance metrics, including illuminance level and uniformity ratios, were calculated to make quantitative comparisons between the light performances of the HPS and new light sources. Such information will be useful to state highway and city street agencies in making decisions on their lighting policies and developing technical specifications for use of the new lighting technologies in roadway and street lightings. Also, such information is useful for manufacturers to improve their luminaire design and integration to better fit the needs of roadway and street lightings.