Why are the streetlights purple on I-96 near Lansing?

The streetlights on I-96 near Okemos Road

When driving on I-96 just east of Lansing, the streetlights suddenly change from their normal hue to a purple glow.

For a short stretch near the Okemos Road exit, the freeway looks like it is under a blacklight.

But is there a reason the streetlights are purple? Well, not really – it's not intentional or intended. 

According to the Michigan Department of Transportation, the LED bulbs are five years old and at the end of their lives. The voltage is correct, but as these lights age, their LED panels diminish, causing them to change color.

The same thing happened to streetlights along I-69 near Saginaw Road.

MDOT said the bulbs are expected to be changed soon.