What is preventing them to let through traffic go before left turns? The light at Lake Shore and Windermere is setup like that.
I'm trying to remember, I haven't been in the city much by car since COVID hit, but yes, Lake Shore and Windermere (I think it was Ellis or Humber Station which also use it) use the lagging FPLT, a rarity in Ontario. I'm no traffic engineer (at least yet) but I've always wondered why they are reluctant to use lagging FPLT especially in transit ROW situations.
Again, one of those streets, it's either Humber Station or Windermere uses lead/lag FPLT, that is one side gets a leading fully protected left turn, and at the end of the cycle, the other side gets a lagging fully protected left turn.
Someone explained to me once the concept is based on "driver expectancy", here in Ontario, we always expect a protected turn, whether it's FPLT or PPLT, to be leading, that is to occur before the main signal (generally for going straight) turns green.
Lagging PPLT movements are incredibly rare in the city on a side note, I think Lake Shore/Yonge is the only example I can think of, except in that case, the protected turn doesn't protect against oncoming traffic but against pedestrians.
I could get into a glossary of all these terms, but I thought way back when, the endgame for the Crosstown (maybe not entirely because of the significant grade separated underground portion), Finch West, and all other Transit City routes as being rebranded as 500 series routes. Ever since 2008 when I looked at this, I've always wondered, what exactly makes the 512 St Clair different from the Finch West LRT other than stops being further apart? Remember, the Harbourfront route was once Route 604 and appeared on the full map (not the subway diagram) as a service being on par with the subway/RT.
Every time I ask that question, many people got extremely angry so I didn't bother. That student in the BlogTO echoes the same thoughts I had at his age regarding this and it's something to be considered.
(If someone needs definitions for FPLT, PPLT, and so on, I can give them on another thread)