Advances in street and roadway luminaires, featuring light sources with long life expectancy, have shown superior photometric performance and energy-saving advantages compared to legacy high-pressure sodium (HPS) lighting. In recent years, the front runner has been the LED. Other light sources such as plasma devices and induction lamps have also seen modern developments for street and area lighting. However, to date, the conversion of conventional HPS-based lighting has been led by conversion to LED-based luminaires.
Organizations such as the IESNA, US DOE, ANSI and NEMA have all focused and developed guidelines for LED device performance prediction over time and especially depreciation- projection methodology. However, there have been few, if any, guidelines for reliability prediction models for power supplies in outdoor LED luminaires.