For what it’s worth, I don’t think it’s necessary to record every detail about signal phasing. But without a way to record protected turns and a consensus on turn-on-red restrictions, this feels like the tail wagging the dog. The result is that shared_green=yes and shared_green=no end up being required in so many cases based solely on intersection geometry, yet a data consumer won’t be able to make strong assumptions based on either value.
As far as I know, protected turns must be verifiable: either the vehicular signal has an arrow lens instead of a ball lens, or the intersection has a separate signal with a sign saying it’s a dedicated left turn signal. Otherwise, the motorist has no way to know that oncoming traffic could stop for them.
Conversely, some jurisdictions use a flashing yellow phase or put up signs to remind motorists to yield to oncoming traffic, which affirms that the turn is unprotected, though this isn’t universal.
Jofban
(Jofban)
22
Yeah, I also have difficulty to find crossings with shared_green=no. Even the examples I know are mostly trivial (i.e. following the rule that through traffic doesn’t share green with crossing pedestrians and for one reason or another, no right turn into it is possible).
