As for your grade-separation: First, I would add the DVP ramp terminal to your list of key locations. I also think there comes a time when over 80% or 90% of the line is already grade-separated - it make sense to make the whole thing fully grade-separated.
We agree that we need more grade separation than is planned. But I don't think there is necessarily much benefit from going from mostly grade-separated to completely grade-separated. Some intersections could provide absolute or near-absolute transit priority, so it would make no difference to speed if they were grade separated.
I don't think the DVP is a particular threat to transit speed despite its high volume, because it could be an intersection with absolute transit priority. Thanks to its simple two-phase cycle, all it would take is to modify the
current design to include median pedestrian refuges (
like this).
If the transit vehicle detector is located 237 metres* ahead of the intersection, transit vehicles can be guaranteed a green light given a cruising speed of 60 km/h.
In the current design, the crosswalk is roughly 25 metres wide, so its 21 second countdown would require LRVs to be detected 487 metres away. Absolute priority could not be implemented because there are LRT stops and other signalized intersections within that distance, preventing signals from predicting LRVs' exact arrival time.
*CALCULATION (in case you were wondering):
Using standard City of Toronto values:
Walking speed = 1.2 m/s
LRT ROW width = 7m (estimate by me, couldn't find exact value)
Therefore pedestrian countdown = 6 s
Maximum signal reaction time (time from detection to transit green) = Ped Countdown + Amber + All-Way-Red = 6+3+3 = 12.
But to make the detector distance more reasonable, I assume that there is some kind of advance indication about when a green light will be provided, such as a flashing red transit signal during the AWR which would reduce the effective signal reaction time to 9 s.
At 60 km/h, a vehicle covers 150 m in 9 seconds. So LRT will get flashing red 150 metres after it is detected.
But the driver needs to obtain confirmation from the signal further away from the intersection than the vehicle's minimum stopping distance, otherwise they need to start braking on the chance that the light does not turn green in time. Assuming a deceleration of 1.6 m/s[SUP]2[/SUP] (from ALRV specs), the stopping distance from 60 km/h is 87 m.
Therefore if the vehicle is detected 237 metres in advance of the signal, it can be reasonably expected to not even slow down. The exception is if they are detected less than 6 seconds after the start of the DVP off-ramp phase, since the city requires is a minimum green length of 7 seconds (6 for turn signals). But even then, the signal would turn green at most 7 seconds later than normal, which is before the LRV comes to a complete stop.
