LED traffic lights trouble in winter because they don’t melt … here might be a solution.
A team of Japanese scientists are turning a curious high school student’s experiments with yogurt container lids into a potential way to keep snow from building up on light-emitting diode traffic lights in cold climates.
The researchers from Kyoto University are developing a snow-repelling coating based on an idea from 17-year-old Mai Idoue, a third-year student at Nakui Agricultural High School in frigid Aomori Prefecture at the northern tip of the island of Honshu.
Authorities across Japan are increasingly replacing traditional bulb traffic lights with LEDs for their lower energy consumption and longer life, but heat generated by an LED chip is dispersed by a heat sink on the back side, making them prone to a build-up of snow on their surfaces that reduces visibility.
Having noticed the snowed-up lights on her commute to the school in Nambu, Mai guessed the water-repellent surface on the underside of certain yogurt lids might do just as good a job of repelling snow.
Looking into the lids’ design, she found they are coated in minute bumps, inspired by the surface of lotus leaves, which allow liquids to roll off.
“If applied to the surfaces or covers of traffic lights, this might make it harder for snow to stick,” Mai thought.
An experiment at school delivered promising results. When Mai stuck a lid with the lotus coating and an uncoated lid to the outside of a classroom window on a snowy day, she found that hardly any snow built up on the coated lid.
Mai’s observation took the grand prize at a Kyoto University contest held last November to solicit fresh ideas from high school and university students.
Her high school and the university signed an agreement in March to jointly develop the technology.
According to Aomori prefectural police, the LED traffic lights use just one-sixth of the electricity of bulb lights and are more durable, but their surfaces are about 20 degrees cooler.
This leaves police officers with the job of wiping accumulated snow off the lights with long poles.
“It may be a challenge to put (the idea) to practical use because snow quality and snowfall patterns differ from region to region, but we’d like to find solutions to these issues,” said Eiichiro Matsubara, materials science professor at Kyoto University’s Graduate School of Engineering.
The university team hopes to develop a prototype in time to test its effectiveness on the high school’s grounds next winter.