advertisement

Energy-efficient traffic lights can't melt snow

Tuesday, December 15, 2009 | 4:35 p.m. CST; updated 4:58 p.m. CST, Tuesday, December 15, 2009

MILWAUKEE — Cities around the country that have installed energy-efficient traffic lights are discovering a hazardous downside: The bulbs don't burn hot enough to melt snow and can become crusted over in a storm — a problem blamed for dozens of accidents and at least one death.

"I've never had to put up with this in the past," said Duane Kassens, a driver from West Bend, Wis., who got into a fender-bender recently because he couldn't see the lights. "The police officer told me the new lights weren't melting the snow. How is that safe?"

Many communities have switched to LED bulbs in their traffic lights because they use 90 percent less energy than the old incandescent variety, last far longer and save money. Their great advantage is also their drawback: They do not waste energy by producing heat.

Scott Bitterman, a Columbia traffic engineer, said the city uses LED traffic lights in all of its stop lights and has been through winter with them before. He said he is not aware of any problems with snow covering the lights in Columbia.

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, "as far as I'm aware, all that can be done is to have crews clean off the snow by hand," said Green Bay, Wis., Police Lt. Jim Runge. "It's a bit labor-intensive."

In St. Paul, Minn., for example, city crews use air compressors to blow snow and ice off blocked lights.

Some communities began installing cool-burning LEDs more than a decade ago, and it wasn't long before drivers started complaining about the problem.

Illinois authorities said that during a storm in April, 34-year-old Lisa Richter could see she had a green light and began making a left turn. A driver coming from the opposite direction did not realize the stoplight was obscured by snow and plowed into Richter's vehicle, killing her.

"Would the accident have occurred if the lights had been clear? I would be willing to bet not," Oswego Police Detective Rob Sherwood said.

Authorities said dozens of similar collisions have been reported in other cold-weather states, including Iowa and Minnesota.

Not every storm causes snow to stick to the lights, but when the wind is right and the snow is wet, drivers should beware, said Gary Fox, a traffic engineer for the city of Des Moines, Iowa.

Exactly how much a technological fix will cost is unclear, but it will surely cut into the savings and the energy efficiency many cities are enjoying.

Wisconsin, which has put LED bulbs at hundreds of intersections, saves about $750,000 per year in energy costs, said Dave Vieth of the state Transportation Department. LEDs installed seven years ago are still burning, while most incandescent bulbs have to be replaced every 12 to 18 months, he said.

"With LEDs we have energy savings in excess of 80 percent, and we don't have to have crews replacing them as often," Vieth said. "So it's clear the overall savings are pretty significant."

In Minnesota, authorities are more than halfway to their goal of upgrading the state's 1,300 or so traffic lights to LEDs. The Transportation Department occasionally gets reports of an obstructed light, but often by the time a highway crew arrives, the wind has knocked out the snow and ice, said traffic systems specialist Jerry Kotzenmacher. Minnesota is experimenting with weather shields.

One reason there have been so few deaths is that drivers know they should treat a traffic signal with obstructed lights as a stop sign, traffic experts say.

"It's the same as if the power is out," said Dave Hansen, a traffic engineer with the Green Bay Department of Public Works. "If there's any question, you err on the side of caution."

—Missourian reporter James Patrick Schmidt contributed to this report.


Like what you see here? Become a member.


Show Me the Errors (What's this?)

Report corrections or additions here. Leave comments below here.

You must be logged in to participate in the Show Me the Errors contest.


Comments

Leave a comment

Speak up and join the conversation! Make sure to follow the guidelines outlined below and register with our site. You must be logged in to comment. (Our full comment policy is here.)

  • Don't use obscene, profane or vulgar language.
  • Don't use language that makes personal attacks on fellow commenters or discriminates based on race, religion, gender or ethnicity.
  • Use your real first and last name when registering on the website. It will be published with every comment. (Read why we ask for that here.)
  • Don’t solicit or promote businesses.

We are not able to monitor every comment that comes through. If you see something objectionable, please click the "Report comment" link.

You must be logged in to comment.

Forget your password?

Don't have an account? Register here.

advertisements