As a motorcyclist, I'm going to disagree completely if the standard technology that is used to detect cars is used. Generally there's some sensor in the road that detects a large metal object above. If you're riding a 400 pound motorcycle, it doesn't trigger.

I've sat at lights for several cycles trying to get a left turn signal, only to be required to run the light (illegally) to get through while traffic built up behind me. Not cool. They need a better way of sensing cars.