MnDOT’s Energy-Saver Lights Snarl Traffic in Storm

MnDOT’s rush to go green just hit what could be more than a bump in the road. The Pioneer Press points out this week’s ice and snow storm exposed an embarrassing downside to the widespread use of LED traffic control lights in cold weather states like Minnesota.

Drivers found out the hard way that LEDs don’t let off enough heat to melt ice and snow on traffic lights like conventional bulbs. That can turn the high tech lights into something of a roadway hazard in themselves.

Energy-efficient traffic lights on Minnesota 36 in Oak Park Heights caused a major problem for eastbound drivers Tuesday morning after the lenses became encrusted with ice and snow overnight.

“They couldn’t see the red light,” said Police Chief Brian DeRosier. “They kept going through the stoplights because they thought they were green.”

The energy-saving lights were part of the new St. Croix River bridge. MnDOT personnel eventually came out to dusted off the ice-glazed lights before anyone got hurt. But it turns out that MnDOT was apparently already well aware of the problem and potential hazards posed by the high-efficiency LEDs.

 A MnDOT spokeman said Minnesota and other northern states are looking for solutions.

“This is a common issue anywhere there are LED lights and snow and ice,” said Kevin Gutknecht, the agency’s director of communications.

The new LED stoplights are 90 percent more energy-efficient than older, incandescent lights, but “they emit much less heat,” he said. “Incandescent lights emitted enough heat to help melt off snow and ice.”

The question is how many more Minnesota highways and roads have LED traffic lights that could produce a similar safety hazard in severe weather. And what’s MnDOT going to do about it?

Oak Park Heights Mayor Mary McComber said she hopes MnDOT comes up with a plan — and quick.

“This was just the first big (weather) incident of the winter,” she said. “We can’t have this happen all winter.”