You need proper TSP like you see with ION, not just extended greens.
Toronto's TSP system is not just extended greens. It can do everything a signal could possibly do to prioritize transit: extend greens, shorten greens, change the order of phases and add additional phases.
The difference between the systems is in the logic used to determine how/when to apply these actions. Like I said in the post you're quoting.
I've certainly seen traffic lights in Toronto that go to flashing countdown in a lot less than 7 seconds!
First of all, no you didn't - the minimum Walk in Toronto is 7 seconds. A signal will literally shut itself down if it detects a Walk duration shorter than that.
Second of all, what does that number prove about signal priority? Just because the countdown started doesn't mean you can give a green light to transit. There are still pedestrians in the intersection!
The issue is the TOTAL minimum duration of a pedestrian phase. That includes:
- Minimum Walk (almost always 7 s, but sometimes 8)
- Flashing Don't Walk (1.2 m/s, sometimes 1.1)
- Pedestrian All-red (at least 4 seconds, but usually equal to the amber+all red of the adjacent vehicle phase)
If you're just clearing pedestrians across the tracks, this is pretty short and it's totally practical to guarantee a green even with a TSP system like Toronto's that only detects trams within the same block (or occasionally an adjacent block). But if you're trying to get pedestrians all the way acros Finch Avenue it could take ages. So if you want to guarantee a green you either need to detect trams minutes in advance (like Waterloo does), do massive green extensions (like some US and Alberta light rail systems do), or cut the crossing up into multiple stages (like the Netherlands and France do).