Does the Valley line currently operate with full signal priority, or do trams stop at red lights?
A list has previously been posted if which intersections have priority or not. Contrary to another post, at Downtown signals the LRT does not have priority. It might seem like the train does, but that's just because it departs the stations when the traffic light is favorable. 97 St often stops trains.
And while at the majority of intersections the LRT has priority, that doesn't necessarily mean it gets automatic greens. If the train ends up out sync with the lights it will get slowed down. As an example, I've seen a train approaching an LRT signal that was a flashing vertical bar which means basically the same as a flashing pedestrian signal. Finish crossing if started, but stop if you haven't started. We stopped, but only briefly as the traffic light aborted it's sequence and we got a solid vertical bar and the traffic light remained green. Or, on approaching 34 Ave with a flashing vertical bar, we stopped, traffic light went red, east/west traffic recieved a green, but it was a short green. North/south traffic and the LRT then recieved proceed signals with no directions getting turn signals.
So, although it is considered full signal priority at a lot of intersection, it is not always non-stop. Pedestrian crossings are the worst for this. Pedestrian crossings are always walk signals unless a train requests it. If you are out of sync, the pedestrian crossing often won't start to cycle until the train has pulled up to it and stopped.
Additionally, the signal system is supposed to have a 4 minute count down timer at each intersection before the next train is allowed through in the same direction. I did see this working with Monday's issues. Often though the train will just be held at a station rather than being stopped at a random traffic light.