Use of LED or Other New Technology to Replace Standard Overhead and Sign Lighting (Mercury and/or Sodium)
CAIT project no.: 148 RU9090
Fiscal Year: 2003/2004
Rutgers-CAIT Author(s): Patrick J. Szary, Michael Strizki, Nadereh Moini, Ali Maher
External Author(s): Edward S. Kondrath
Sponsor(s): NJDOT, FHWA-USDOT
The New Jersey Department Of Transportation (NJDOT) has an increasing concern that the quality and energy use for roadway lighting is outdated. The current lamps and energy usage is based on old practices and technologies. To research the state-of-the-art, NJDOT has contracted Rutgers/Center for Advanced Infrastructure and Transportation (CAIT). The main issues to be addressed include: 1) Introduce the existing and latest technologies in roadway lighting, and evaluate the current and proposed alternatives (taking into consideration illumination, visibility, maintenance, spectral power distribution, lumen depreciation, mean life, and color rendering). In addition, the research team is to provide NJDOT with the field verification on two key issues: visibility and color rendering, which are implemented on Sodium and white light sources. 2) Present the life cycle cost analysis on the introduced technologies and compare them to current lamps used in street lighting (High Pressure Sodium), with the proposed alternatives. Thus, the study will provide not only the most cost effective alternative to using High Pressure Sodium in roadway lighting, but also the most practical. Based on the research, white light sources demonstrated superior light quality. QL, Icetron, Restrike HPS, and LEDs were all shown to be equivalent or superior in light quality based on Lumen Effective Multiplier (LEM). Also, based on the Life Cycle Cost Analysis (LCCA) the QL, Icetron, Restrike HPS, and LEDs had superior cost savings. However QL, Icetron, and LED may not meet current light distribution specifications; which are currently being revised on a national level.
In summary, Restrike HPS lamps are recommended for immediate implementation; whereas QL, Icetron, and LED should wait for acceptance on a national level. In some situations where lighting is not specifically governed by the specifications, and NJDOT would like to further evaluate the technologies, QL type lamps are recommended for implementation.