Purple "Rain" – LEDs casting a purple glow on Oregon Highway 34

    If you’ve recently driven on Oregon Highway 34, you may have noticed the street lights going from the typical halogen-type that cast the nostalgic “yellow” and buzz noise have been replaced with the more modern LED-style light.

Photo by Skylar Wilkerson
Intersection with Oregon Highway 34/Denny School Rd.

But there’s something different about them … as they cast a purple glow?

 

At a Glance: What: Purple “Rain” – Purple LEDs casting a purple glow on Oregon Highway 34 Why: A manufacturer defect in the LEDs The Cause: LEDs naturally emit blue/purple light. They are typically covered in a phosphor coating to turn that light white. When the coating degrades or fails, the original purple hue leaks through. What’s Next: Replacing the affected fixtures in the next 10-12 weeks is estimated at $20,000 for time and materials. Website: www.oregon.gov/odot/engineering/pages/illumination.aspx For More Information: www.oregon.gov/odot/pages/media-contacts.aspx

    Taking notice of these off-colored lights during a drive home one night in the rain, one could only be mesmerized by the purple “rain” cast by the light reflecting through them. The only thing that was missing was Prince, singing “Purple Rain.”

Photo by Skylar Wilkerson
Intersection with Oregon Highway 34/Langmack Rd.

    Some of the questions the lights raise: Have these caused any accidents? What is the cause of these lights going purple? Are they being replaced?

    After reaching out to the Linn County Road Department through email, County Roadmaster Amy Ramsdell replied, “By law, we are not able to perform work on another road authority’s network without their written consent.” She went on to state in the email, “The Linn County Road Department will not be replacing lights on the Oregon Department of Transportation network.”

    ODOT Public Information Officer Mindy McCartt wrote, “The purple hue you’re seeing on the streetlights near Oregon 34 at Goltra Road and Denny School Road is a known issue affecting some LED fixtures nationwide. In this case, it is due to a manufacturing defect where the phosphor coating on the LED degrades over time.”

    McCartt went on to state, “LED lights naturally emit a blue or purple light, and the coating is what converts that to the standard white color. When the coating fails, the light can appear purple.”

    “These particular lights were installed by a contractor about nine years ago and are outside the standard warranty period,” McCartt wrote. “ODOT maintenance crews recently inspected the site and confirmed that all but two of the fixtures have a purple hue. Replacing all the affected fixtures is estimated to cost approximately $20,000 in time and materials. Because of the volume of business ODOT does with the supplier, we are exploring options to obtain discounted replacement fixtures. That process requires verifying the age and manufacturing batch using serial numbers. We estimate the repairs will take place within the next 10–12 weeks.”

    McCartt also addressed the safety concern for these lights: “We are not aware of any crashes specifically attributed to the purple lighting at this location. While the color is unusual, the lights are still functioning and providing illumination.”