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 Minnesota Department of Transportation installed the LEDs as part of the new St. Croix River bridge project. Because the lights don’t emit much — if any — heat, ice and snow can accumulate.

“It was the perfect storm, if you will, because we had the ice and the wind and the snow and the cold,” DeRosier said. “The wind blew it, literally, into the lenses.”

Problems were reported at Washington Avenue/Norell Avenue, Oakgreen Avenue/Greeley Street and Osgood Avenue. Police heard “lots of radio chatter” about possible and near-misses, especially on Oakgreen, but received only one report of an accident with physical damage — at Washington/Norell, DeRosier said.

“Thankfully, there were no serious accidents,” he said. “But it caused problems for people who wanted to go north and south across the highway and couldn’t get across because the traffic wouldn’t stop.”

MnDOT crews responded to the scene and cleared the lenses, DeRosier said.

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.”

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.”