stop light radio static.

[sde]

a lot of times when i pull up to a stop light, my radio station (not a very powerful one) gets overcome with static.

what do stop lights emit that causes this?

[Belisarius]

Got me - been using XM for the better part of 8 months now. If I go behind a good-sized hill it cuts out, but that's about it (apart from parking structures).

Does it happen at all stop lights, or a particular one? Does it happen when you just stop, regardless of a light or not?

[sde]

i mainly notice it on my way to work. it's only at stop lights. i only have a 6 mile commute, so maybe it's just something about the stop lights in the area.

[DJMaze]

mostly stoplights use leds instead of bulbs since leds are better when the sunlight hits them.
These leds do produce frequencies that could pollute radio frequencies but the question does remain which.

Here in the Netherlands we have no issues, maybe it's because of the flat land.