Tuesday, December 15, 2009

A green light?

From the laws of unintended consequences department:

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 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.

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.

Now, I understand that we want to save energy, and that using energy-efficient lights in situations where lights are burning nearly all the time makes sense. But does it make sense to put lights in cold climates which then have to be painstakingly cleaned by hand? How much energy does that use?

And if a technological fix is adopted, will the energy spent by the fix plus the lights be similar to the energy used by the old incandescents? What will the fix cost, and how does that compare to the cost of the old bulbs?

While it's praiseworthy to want to conserve energy, that doesn't always mean rushing to adopt some new change just because it's more energy efficient. Only when we've considered the full impact of the new technology should we proceed. I find it amazing that in some places these LED traffic lights have been used for more than a decade--and, presumably, for more than a decade road crews have painstakingly gone out after each blanketing snow or ice storm to clear the lights so that traffic can proceed safely.

We don't want to rush to give a green light to all new, presumptively "green" technology, until we've considered all the consequences. When energy savings can be found without risking public safety or increasing costs to an unbearable level, adopting them makes sense--but we need to make sure we're not increasing risks or costs too much before we hail these new inventions as "solutions" to the older, less efficient technologies they're replacing.


Tarcisius said...

Ah, but if they have to be cleaned off, doesn't this "create jobs?" /sarcasm

Red Cardigan said...

Excellent point, Tarcisius!

Badger said...

We get fewer than two dozen snowfalls a year. Of those, maybe a half dozen to a dozen would affect stop lights.