Current solutions to the snow-clogged signal lights include manual labor of brushing snow off of the signal lens and spraying de-icing chemicals on the lens to prevent the buildup of snow and ice. These manual methods are laborious, adding an annual maintenance cost of $30.60 /signal light. Chemicals may also be harmful to the signal lens and the local environment. Most of the electricity consumed by the LEDs actually becomes heat (70%) rather than light. The self de-icing LED signal light has self-efficacy for prevention of the buildup and accumulation of ice, sleet, and snow on the lens of the signals during wintery conditions. There is no need of additional heat generators (e.g., resistance wires or infrared LEDs) and sensors to control them. The self de-icing LED signal light harvests both the light and the heat generated by the same LED, thus, is more energy efficient than the existing “cool” LED signal light. Given that 39 states and over 70% of the population of the United States and the entire country of Canada are located in snowy regions that receive at least five inches of snow each year, this problem of snow-clogged “cool” LED signal lights in cold winter is a very typical and expansive problem in which a viable retrofit has not been developed or tested that does not compromise the efficiency, brightness, and operation complexity of the system. The new self de-icing LED signals have two significant benefits, including (i) safety and performance efficiency and (ii) overall user cost savings, which are expected to transform the use and operation of the existing signal lights in snowy regions in North America. Once validated in this proposed project, the self de-icing LED signal light is expected to be a viable retrofit to the existing “cool” LED signal lights and other obsolete energy inefficient incandescent signal lights installed at the highway signalized intersections and railroad wayside and at-grade crossings. Additionally, the self de-icing LED signal light is expected to extend into other rail applications (e.g., commuter or light rail), or in other surface transportation applications including airport taxiway/apron lighting and seaport applications located in cold weather zones. Although the self de-icing LED signals are targeted for colder weather regions, they can certainly be installed in warmer climate where they may see only a limited number of cold weather days.

This proposed project will develop multiple prototypes of a new type of self de-icing LED signals for highway signalized intersections and railroad signaling applications and validate them using the field tests. The innovative concept — “Heated Lens Lighting Arrangement” — was thoroughly tested in 2014. A non-provisional patent application (No. PCT/US14/53503) was filed on Aug 29, 2014. The self de-icing LED signal light is aimed to solve a well-known problem of the existing LED signal light that does not generate sufficient heat in the forward direction towards the lens of the signal necessary to melt snow and ice. Snow and ice can easily accumulate on the lens within the signal hood in wintery conditions and block light to the drivers of vehicles or locomotive engineers. This can decrease the performance of signalized intersections and railroads and also result in collisions in inclement weather conditions. This is a problem in the snowy regions in North America for which a viable retrofit has not been developed or tested.

This proposed research project will develop and test different types of prototype self de-icing LED signals over a project period of three years. Such a long project period is needed because the prototypes need to be tested first in a closed-course setting and then in the field in sequence of two cold winter seasons. The prototypes will cover all types of the existing LED signals used in highway signalized intersections and railroad signaling applications, including highway intersection traffic signals (8” and 12”), repeater signals (100 mm), arrow signals (12”), pedestrian signals (12”, 16”x18”), railroad wayside signals (5 ½”, 8”, 12”), rail transit signals (12”), rail level crossing signals (6”, 8”, 12”) in red, green, yellow, lunar, and white light colors. The plan of work includes nine tasks divided into four stages: (i) laboratory development and tests of the prototype self de-icing LED signals, (ii) tests of the prototypes on the roof of the engineering complex and refinements, (iii) field tests of the prototypes on identified highway signalized intersections and rail track sections as well as on-site demonstration, and (iv) project briefing and final report.

$300,000 is needed for this study. We are looking for 5-6 partners to committ $20,000 per year for three years. 100% SPR Funding has been requested. The TRB Rail Safety IDEA program has committed $50,000 and the TRB NCHRP Highway IDEA program has committed another $50,000, totaling $100,000 to fund an associated project, Self-Deicing LED Signals for Railroads and Highway Intersection.