While listening to an FM radio station (frequencies between 88 and 108 MHz) in my car, I've noticed that as I pull up to a red light, there's an increase in the amount of noise. It's very noticeable when I'm listening to a station that's somewhat far away, so I'm at the edge of the region in which reasonably noise-free reception is possible.
As I'm approaching the red light, and stopping, the lights in the perpendicular direction are green. When those green lights turn yellow, the noise suddenly drops. Then when those lights have turned red and the lights in my direction turn green, the noise comes back. Then I go through and as I get farther from the green light, the noise fades.
It's not a single weird intersection; I've heard it in multiple locations. The noise increase and decrease is perfectly synchronized with the change of light color. I believed it was a coincidence for a while, but I've heard it too many times now. It's a real effect. Being near a green light causes radio noise. Why?