Originally Posted by
livedarklions
You're technically right, but inductive loop triggers do exist and they require a very large amount of metal to trigger the light change. Still requires a lot more metal than I can carry on a bike, so in practice no difference in effect--I'm just not magnetic enough to trigger the light because I'm not carrying hundreds of pounds of metal..
...
The sensors can be adjusted to be triggered by bikes, even non-metal bikes. (Maybe not all but plenty in Portland trigger nicely.) But someone has to do this. Spec the appropriate sensor, set it correctly and see to it that we know where to place our bikes. Paint a marker after re-paves for example. I don't believe any of this is especially difficult but even in bicycle-centric Portland, this doesn't happen in many places.