If the light is green you go. If it’s yellow, prepare to stop. If it’s red, come to a full stop.
But what do you do if your traffic signal is white?
Some Long Island drivers had to deal with that conundrum Thursday morning, as windblown snow collected in traffic- light fixtures and obscured the signal. The problem was observed along parts of Route 110 and New York Avenue, north-south arteries that traverse the Town of Huntington in western Suffolk.
The cause is linked to traffic signals that use LEDs, or light-emitting diodes, instead of incandescent bulbs. LED lights are brighter, last longer and save energy. But they also generate less heat and the snow on them doesn’t melt as fast.
“It’s a new phenomenon ever since they put up the LED lights because they don’t produce the same heat,” said Lauren Lembow, spokeswoman for the Town of Huntington.
The issue is not confined to Huntington — or Long Island for that matter — but has been observed in the Northeast and in Canada.
“It is something that I guess those of us who live in what seems to be a never-ending winter are experiencing — when you don’t see a traffic light you have to assume it’s a red light,” said John Bullough, a scientist who is director of transportation and safety-lighting programs with the Lighting Research Center at Rensselaer Polytechnic Institute in update Troy.
LED traffic signals are a smart choice energy-wise because they have about 25 times longer life than incandescent bulbs and use 10 percent to 15 percent of the power, leading to less maintenance and fewer breakdowns, Bullough said.
Older traffic lights were powered by filament-burning bulbs behind colored glass, and they generated heat as well as light.
“If anyone encounters a traffic signal that is either not functioning or covered with snow, they should treat the intersection as a ‘four-way’ stop and then proceed through the intersection with caution,” said Stephen Canzoneri, the state Transportation Department’s spokesman on Long Island.
The LEDs produce light on a specific wavelength to replicate a color, and the heat coming off them is confined to a chip, Bullough said. The traffic signals can be improved, he said, by directing the heat to the surface, as has been done with taxiway and runway lights.
“In principle, there’s nothing to say they [manufacturers] couldn’t have fixtures made that conduct that heat out,” Bullough said.
While the technology catches up with cold-weather needs, Bullough said there’s one old-fashioned fix used in some places: Send snow-clearing crews out with very long broomsticks.