> Cyclist aren't massive nor hot, on a hot summerday they will be cooler than the road surface. I think a camera with object recognition or something similar should be able to do it.

I don't know the technical details on how it's done here in Stockholm, even less in the suburbs where I've lived but it feels like magic that in some traffic lights in busier intersections they'll just trigger by themselves with enough distance that when I arrive with the bike at the intersection the lights are turning green for me.

I have looked for cameras but couldn't find them, it's even more puzzling in a specific intersection close to my house where I bike along a 4-lane road with only fields of wheat and grass, and the intersection I cross leads to an industrial area, there are only the posts for the pedestrian/bike lights and those still turn green, no cameras in sight, no detection trap on the pavement.

In Stockholm, we have 2 sets of sensors dug :

1. induction coil sensor dug in road at the traffic light

2. radar sensor at 100-200m from the traffic light

It feels like magic because if you hit sensor (2) and there are no other competing cars, the traffic light changes for you and you don't have to slow down.

This is the best solution. In Dublin, they only have sensor (1) and it feels really slow in comparison. You keep having to stop and start.

Indeed, here in Linz the few intelligent traffic lights we have are mostly for cyclists and the detection works great. On the three bridges there are counters that differentiate between trucks, cars, cyclists and pedestrians and they also work great.