Re: I despair
"Why not use independent sensors that "see" what's really there?"
Indeed, traffic lights with cameras and/or under-road sensors seem to work perfectly well around here, including turning green in plenty of time to drive through without slowing down if no other cars are around. Replacing that with a system that requires every vehicle to have a broadcast device fitted adds a huge amount of complication and vulnerability without adding any real benefit. And of course, since you can't rely on all vehicles actually having it, you still need an entire normal system working in parallel anyway.