This project developed and demonstrated a new type of self-de-icing LED signals for highway and railroad intersections, as a replacement for the existing LED signal lights that remain too cold on the signal lens to deice or melt snow and could cause accidents in snowy conditions. The self-de-icing LED signals adopt an innovative system architecture of “Integrated Light and Heat Arrangement of LEDs in Low Profile” that was patented (US 10,253,965 B2, US 10,215,441 B2, US 9,851,086 B2). The heat generated by the LED(s) is harvested by the passive heat exchanger and stored to heat the lens for melting snow and de-icing in wintery conditions. The prototype signals in red, yellow, and green light color consist of a new signal housing, three new light engines in different light color (R, Y, G), two custom-made LED drivers integrated with a remote temperature sensor for controlling the signal power output in light of the ambient air temperature and an on/off switch for winter and summer modes, new signal lens integrated with 96 small fresnel lenses for light collimation of individual LEDs, and insulation materials as part of the innovative system architecture. This project developed and tested four generations of fully working prototype signals in the laboratory and then on the roof with continuous improvements on their heating and lighting parameters with the desired specifications, followed by field testing on identified highway signalized intersections and rail track sections. The prototypes, once validated in the closed-course setting, were installed on pole-mounted side signals as backup to the existing primary signals and commissioned. A field monitoring system was built in-house for monitoring the real-time performance of the prototypes in field for melting snow and deicing with year-around data recording.
Seven states (Kansas, California, Michigan, New Jersey, Wisconsin, Pennsylvania, and Maryland) are participating in field testing and evaluation of the prototypes. The first field test site was set up in Kansas at the intersection of County Rd 458/US-59. More prototypes of the final products are in preparation for other test sites in California, Michigan, Wisconsin, Maryland, and New Jersey & Pennsylvania. Other agencies in private sector such as Union Pacific (UP) Railroad and Burlington Northern and Santa Fe (BNSF) railroad would be contacted for their participation in the project for testing railroad signals in the field. On-site demonstration of the prototype signals would be held for project partners and state DOTs to initiate the implementation process. The self-de-icing LED signal lights were designed to be swappable with the existing “cool” LED and incandescent signal lights without needs of extra installations other than “re-lamping”. As proven in the field test in Kansas, this system does not alter the function and sizes of the existing signal lights. No need to add additional wiring inside and outside of the existing signal controller cabinets, or change anything outside of the signal housing. The self-de-icing LED signal is expected to transform the use and operation of the existing signal lights in snowy regions in North America with significant benefits in safety and performance efficiency and overall user cost savings.
The final report is available.