1overcosc
Active Member
That's Toronto's fault for not managing them properly. A well designed signal priority system can give greens >95% of the time.
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That's Toronto's fault for not managing them properly. A well designed signal priority system can give greens >95% of the time.
nfitz
Superstar
But we live in Toronto. Let's go with what works here, not works on paper.
TheTigerMaster
Superstar
Metrolinx had better hold Transportation Toronto's feet to the fire, regarding signal priority. They can't screw up things on the LRT lines like they did with the 512 a few months ago.
crs1026
Superstar
That approach would pretty much preclude a lot of tried and true solutions from other places. One being transit priority and after-intersection stops.
I have no stats on how much of it we have in TO, versus how much other cities have, but transit people tell me Toronto is not a leader, and the traffic folks are resistant. Spadina being a good example.
Portland is a place that comes to mind where it is really well implemented - the downtown is a grid with short blocks and hence many stop lights. The streetcars just sail thru it all.
- Paul
reaperexpress
Senior Member
Installing near-side stops is basically a permanent exclusion of TSP ever working efficiently. I did a review of signal operation on King Street near the end of last year, and found that there was very little we could do to reduce wait times at traffic lights because the signal simply can't know when the vehicle is going to enter the intersection in order to provide a green at that time. At the same time, I looked at a couple signals on St. Clair, and they seemed to be working fairly effectively.
It doesn't make sense to build an anti-TSP design based on your impression the current staff. New staff is hired much more frequently than we rebuild our infrastructure. Even now, there are city employees (such as myself!) trying to increase the effectiveness of our current 1980's-era TSP system, and others looking to find a modern replacement for it.
There are two main reasons that the TTC's TSP system is so ineffective and inefficient.
Firstly, each signal separately detects vehicles, so it only gets one city block of advance notice that a streetcar is coming. That works out to around 10-15 seconds at cruising speed. Given that it takes up to 20 seconds to change a red light to green (~12s pedestrian countdown, 4s amber, 2s all-way red), most signals' TSP system is incapable of truncating a red quickly enough for an approaching streetcar to pass through on green.
Secondly, traffic signal operations in Toronto prioritize pedestrians to a very high degree. In order to avoid unnecessary delay, the city prefers to use a TSP algorithm that provides green extensions with a "walk" display, rather than a "don't walk" display. That's something that sounds great in theory, but is disastrous in practice.
To provide a green extension with a "walk" display, decisions about providing green extensions must be made before the start of the pedestrian countdown - 8 to 15 seconds before the start of the actual extension. Given that we only have 10 or so seconds advance notice that a streetcar is coming, you can start to see how our TSP is so horrendously ineffective.
Part of the issue that has existed over the past 20+ years is that we had very little flexibility to adapt the TSP parameters for each intersection based on its individual characteristics. We simply had 4 combinations of walk and don't walk extensions with either 15 or 30 seconds of each. With our new central signal control system that was installed over the past few years, that is no longer a constraint and we can specify anything we like, though at the moment we are still operating with the mostly-arbitrary values carried over from the old system.
In my spare time, I came up with a calculation to determine the optimal parameters at each signal based on the advance notice it gets of an approaching streetcar and the duration of its pedestrian countdown. I have yet to try and get it implemented, but based on a bit of talking to co-workers I think I will be able to do so.
TheTigerMaster
Superstar
Interesting. Do you have any insight on how well signal priority will worth with ECLRT, FWLRT and ELCRT?
nfitz
Superstar
Pretty much. The delayed greens for streetcars after they've stopped at near-side stops work well. The far-side don't. Let's move on ...
SaugeenJunction
Senior Member
W. K. Lis
Superstar
TheTigerMaster
Superstar
Woah. Why does 4406 look so different in the last photo? The wonders of lightning.
Jonny5
Senior Member
They really don't work well for near-side stops. It often causes more delay, not less. That's not working well at all.
drum118
Superstar
4407 & 4408 arrived early on a CP train at Weston Station this morning around 2:30 am while I was shooting and video the various runs of the UPX trains.
Wasn't sure when 4407 was to leave Thunder Bay, but check the trains as they went by and one of then had 4407 on it.
Shock to see 4408 that was about 10 cars behind 4407 considering I haven't heard any news on it at all these day.
Mid April will be when these new cars enter into service. 3 cars entering into service within in one months is great.
Photos and videos to follow shortly.
Wasn't sure when 4407 was to leave Thunder Bay, but check the trains as they went by and one of then had 4407 on it.
Shock to see 4408 that was about 10 cars behind 4407 considering I haven't heard any news on it at all these day.
Mid April will be when these new cars enter into service. 3 cars entering into service within in one months is great.
Photos and videos to follow shortly.
nfitz
Superstar
This morning of all days, photos or it's not real ...
yrt+viva=1system
Senior Member
I'm really liking these photos of the PCCs in their modern day reincarnation! It would be cool if some had a flickr gallery of all 204 reincarnations! 
TheTigerMaster
Superstar
So streetcars don't go to heaven after all; they're reincarnated