Japanese LED traffic lights just too cool when snow falls

February 23, 2015
Energy saving traffic lights in Japan are failing to melt snow covering them

Energy-saving LED traffic lights seemed like a cool way to cut back on electricity costs, but Japanese police said Monday they might just be too cool—because they don't melt snow.

Light-emitting diodes (LEDs) account for around 45 percent of all of Japan's stop-and-go signals and that proportion is growing as local authorities cotton on to their economising possibilities compared with regular incandescent lights.

But in wintery northern Japan the lights have encountered a problem—drivers can't see them because they don't get warm enough to melt accumulated snow.

Akira Kudo of Aomori Prefectural Police said snow has to be removed manually between December and mid-February during blizzards.

"We don't have enough staff members to remove as more and more LED lights are being introduced," he said.

LED lighting is becoming ever more popular in public and private spaces because of its lower energy consumption.

The technology has been big news in Japan since three local-born physicists won the Nobel Prize last year for the development of the blue LED, the breakthrough that to the white LED now commonly used worldwide.

Children make snowmen in Iiyama city, Nagano prefecture on February 15, 2015

Explore further: Researchers find LEDs attract more flying invertebrates than conventional lighting

Related Stories

Ornamental plant seedlings grown with LED lights at Purdue

October 29, 2014

Purdue University researchers' success in using red and blue LEDs as the only source of light to grow ornamental plant seedlings indoors has led to a new phase of determining whether they can reduce production time with more ...

Giving LEDs a cozy, warm glow

November 19, 2014

When the 2014 Nobel Prize in physics was awarded this October to three Japanese-born scientists for the invention of blue light emitting diodes (LEDs), the prize committee declared LED lamps would light the 21st century. ...

Taiwan saves electricity with new traffic lights

September 28, 2011

Authorities in Taiwan said Wednesday they had changed more than 690,000 traffic lights throught the island in a project that will save enough electricity to power more than 60,000 homes.

Recommended for you

Fish-inspired material changes color using nanocolumns

March 20, 2019

Inspired by the flashing colors of the neon tetra fish, researchers have developed a technique for changing the color of a material by manipulating the orientation of nanostructured columns in the material.


Adjust slider to filter visible comments by rank

Display comments: newest first

not rated yet Feb 24, 2015
This doesn't seem to be an issue with LED traffic lights in Canada. I wonder what exactly is different.
5 / 5 (2) Feb 24, 2015
This doesn't seem to be an issue with LED traffic lights in Canada. I wonder what exactly is different.

There's heaters installed in them.

De-icing system for traffic signals:

There are simple heating wires with positive temperature coefficient, which are self-regulating in terms of temperature, much like the rear window heaters in cars. A simple thermostat switches them on below a pre-determined temperature where the heat from the LED bulb itself is insufficient to keep the glass clear.

These types of heaters are also necessary in cold and humid environments to prevent frost and fogging of the bulbs. Otherwise there would be ice and water build-up around and inside the enclosures which leads to corrosion and high maintenance costs.

Of course it wastes a bunch of energy, but what can you do?
5 / 5 (1) Feb 24, 2015
This has however been a perennial problem all around the world ever since LED lights started to become substituted for incandecent bulbs in traffic lights.

For example, a news article from 2010:

It's down to the city planners whether they'll install heaters on the bulbs or not, and of course it saves money not to, or they may be ignorant of the option in the first place. Usually the lowest bidder wins and the traffic lights use plain LEDs that can and do get frozen during the winter.

not rated yet Feb 24, 2015
Thank you. That was informative.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.