LED Traffic Lights Can’t Melt Snow

LED Traffic Light

Put this one in the “didn’t see that coming” bin. Virtually everywhere you drive these days chances are you will see one or more LED traffic lights at important intersections. They’re the ones that look like a pattern of bright dots.

Cities around the country have installed these new traffic lights for several very good reasons. They are very energy-efficient using about 90% less energy than their incandescent counterparts and, more importantly, they last tens of thousands of hours, thus saving municipalities a bundle in maintenance costs.

Wisconsin, for example, which has put LED traffic lights at hundreds of intersections, saves about $750,000 per year in energy costs. LEDs installed seven years ago are still burning, while most incandescent bulbs have to be replaced every 12 to 18 months.

All of this sounds terrific! However, a negative side effect, that most of us never saw coming, is that these highly efficient traffic lights sometimes do not generate enough heat to melt the snow and ice that might obscure them.

Not every storm causes snow to stick to the lights, but when the wind is right and the snow is wet, drivers should be aware of this possibility. States reporting this type of problem, thus far, include Wisconsin, Minnesota, Iowa, and Illinois.

This unforeseen but serious problem has now been blamed for dozens of vehicle accidents and at least one death. Because of this, authorities in several states are testing possible solutions, including installing weather shields, adding heating elements like those used in airport runway lights, or coating the lights with water-repellent substances.

Short of some kind of technological fix all that can be done in most cases is to have crews clean off the snow by hand, which is a bit labor-intensive. In some areas, for example, city crews use air compressors to blow snow and ice off blocked lights. Obviously, this type of labor-intensive work can eat into the savings that municipalities had hoped for.

One reason for there not being more traffic accidents is that most drivers know they should treat a traffic signal with obstructed lights as a stop sign. In short, if the traffic signal is obscured by snow and ice, always err on the side of caution and stop.

Tom Farin

Tom Farin is the founder of Pegasus Lighting. Dr. Farin has been in the field of lighting since 1987. He has extensive training and experience in lighting, physics, mathematics and education, acquired at the undergraduate level, in graduate school, and in the field. It is Dr. Farin's interest and expertise in education that has driven the overall design of the www.PegasusLighting.com site - with its heavy emphasis on lighting terminology, lighting techniques, and thorough information on each lighting product.