traffic signal actuators

[Eden]

There are two types of signal actuators: the new optical ones (lives on top of the light, and looks similar to a red-light camera), and the old magnetic ones. I'm pretty sure it's impossible to trigger a magnetic actuator unless you have a steel frame.

This is a common misconception, but the buried type of traffic detectors use induction (similar to a metal detector), not magnetism or weight. Any type of metal will set off an induction loop, so an aluminum or ti frame should set one off just as easily as a steel one (I suppose if you could drag around a bike made of gold that would work too ) . Even a CF bike, if it has metal rims/spokes will set trigger a traffic light that is set up to be sensitive enough.

If you can see the cut out in the road the best place to position yourself is along the edge of the cutout, front wheel angled along the top of the cutout, the whole bike leaned a bit into the loop. Basically making the metal parts of your bike look as big as possible to the detector.