mistersg1
Active Member
I am new here, and some of you may recognize me from AARoads, I post there occasionally and well, I have been following the transportation crisis we have on our hands for over 10 years now. If there was a proper channel to properly introduce myself on the site I would do it lol.
Ok, "Split Phasing" as it's called by the FHWA, or "Separate Phasing" as what it's called by the MTO is a type of signalling I'm very much not a fan of. For those unaware of what this entails, I could show ring and barrier diagrams explaining what a split phase is, but it's best to explain it like this.
Consider Street A runs NB-SB, and Street B runs EB-WB, this intersection is a standard intersection where the two streets meet at 90 degrees.
A split phase is when one street gets its own phase for both directions, for instance, if ONLY EB on Street B could move while WB on Street B faces a red, and then afterwards, ONLY WB on Street B can move while EB faces a red, this is a split phase.
So an intersection sequence would go like this, everything is RED unless specified otherwise:
Street A gets a green light, which turns to yellow and then red
Street B in WB direction ONLY gets a green ball + green left arrow, which then turns to yellow and then red
Street B in EB direction ONLY gets a green ball + green left arrow, which then turns to yellow and then red.
Generally, split phases will happen in places such as for example, in a dual left turn scenario, one of the left lanes is an option lane (you can go left or straight from that lane) In the GTA, split phases generally occur at former T intersections in which the ending street gets extended, as is the case at Spadina/Fort York/Bremner. IMPORTANTLY usually one ped crossing for one of the street B movements is removed, this is indeed the case at the aforementioned intersection.
So let's consider Spadina/Bremner/Fort York
The expansion of CityPlace west of Spadina led to an extension of Fort York Boulevard. Before as we know, Bremner and Spadina met at a T intersection....Bremner's approach to the intersection at the time for lane movements from left to right was, left turn, left turn, right turn.
Along comes the extension of Fort York, and now Bremner's approach to the intersection is currently, left turn, left turn, option lane (straight or right turn), Fort York's approach has two lanes, one left turn lane, and an option lane, straight or right.
So how does this intersection currently operate, this is how the flow goes starting with Spadina's phases:
Spadina (depending on if any vehicles are occupying the left turn lanes) will have a fully protected left turn movement, when this phase ends, the main signal along with the transit signal will display a green ball, and the walk sign will appear....of course, these signals turn back to red.
(Forgive me, I can't remember who moves first, Bremner or Fort York, but I think it's Bremner)
Bremner gets its share of the split phase, green left arrows and green balls are displayed, also, during this phase is the ONLY time the ped signal crossing the north side of the intersection displays a walk sign. This phase cycles back to red like normal.
Fort York gets its share of the split phase, a green ball + green left arrow is displayed, as Fort York is seen as the lesser movement for vehicles wanting to turn left, the traffic engineers must have decided that a pedestrian phase on the south side of the intersection would extend the Fort York phase too much.
And there you have it, anyone who has seen how this intersection operates during PM rush notices a few obvious things, because of the influx of a dual left turn lane onto Spadina, Spadina gets overloaded from traffic from Bremner and traffic travelling south reguarly on Spadina thus runs into a situation where only 3 or 4 vehicles per lane can clear the intersection when facing the green. In essence, those who rat run, and use say Wellington to reach Simcoe, and then make a right onto Bremner are essentially butting the line on Spadina to reach the Gardiner.
The south side should have a pedestrian phase, and this is what I propose, the Bremner approach is redesignated to left turn, straight, right turn, this will be an inconvenient movement for drivers to reach the precious middle lane of Spadina, on top of that Spadina will not get as much as a load from left turning traffic.
Indeed, the split phase should be removed, and Bremner and Fort York should have a fully protected simultaneous left turn, after the simultaneous fully protected turn phase ends, a green ball should appear and a ped signal on both sides of the intersection should display a walk sign.
The real problem to this is if I recall correctly, Fort York has a very small left turn lane that only allows a couple of vehicles to queue (If I remember right).
What do you guys think, I'm no expert, and while I am a mature student of civil engineering, I have never taken any such courses in traffic engineering in my life, I have learned all the terms from observing intersections and independent research on the net.
Ok, "Split Phasing" as it's called by the FHWA, or "Separate Phasing" as what it's called by the MTO is a type of signalling I'm very much not a fan of. For those unaware of what this entails, I could show ring and barrier diagrams explaining what a split phase is, but it's best to explain it like this.
Consider Street A runs NB-SB, and Street B runs EB-WB, this intersection is a standard intersection where the two streets meet at 90 degrees.
A split phase is when one street gets its own phase for both directions, for instance, if ONLY EB on Street B could move while WB on Street B faces a red, and then afterwards, ONLY WB on Street B can move while EB faces a red, this is a split phase.
So an intersection sequence would go like this, everything is RED unless specified otherwise:
Street A gets a green light, which turns to yellow and then red
Street B in WB direction ONLY gets a green ball + green left arrow, which then turns to yellow and then red
Street B in EB direction ONLY gets a green ball + green left arrow, which then turns to yellow and then red.
Generally, split phases will happen in places such as for example, in a dual left turn scenario, one of the left lanes is an option lane (you can go left or straight from that lane) In the GTA, split phases generally occur at former T intersections in which the ending street gets extended, as is the case at Spadina/Fort York/Bremner. IMPORTANTLY usually one ped crossing for one of the street B movements is removed, this is indeed the case at the aforementioned intersection.
So let's consider Spadina/Bremner/Fort York
The expansion of CityPlace west of Spadina led to an extension of Fort York Boulevard. Before as we know, Bremner and Spadina met at a T intersection....Bremner's approach to the intersection at the time for lane movements from left to right was, left turn, left turn, right turn.
Along comes the extension of Fort York, and now Bremner's approach to the intersection is currently, left turn, left turn, option lane (straight or right turn), Fort York's approach has two lanes, one left turn lane, and an option lane, straight or right.
So how does this intersection currently operate, this is how the flow goes starting with Spadina's phases:
Spadina (depending on if any vehicles are occupying the left turn lanes) will have a fully protected left turn movement, when this phase ends, the main signal along with the transit signal will display a green ball, and the walk sign will appear....of course, these signals turn back to red.
(Forgive me, I can't remember who moves first, Bremner or Fort York, but I think it's Bremner)
Bremner gets its share of the split phase, green left arrows and green balls are displayed, also, during this phase is the ONLY time the ped signal crossing the north side of the intersection displays a walk sign. This phase cycles back to red like normal.
Fort York gets its share of the split phase, a green ball + green left arrow is displayed, as Fort York is seen as the lesser movement for vehicles wanting to turn left, the traffic engineers must have decided that a pedestrian phase on the south side of the intersection would extend the Fort York phase too much.
And there you have it, anyone who has seen how this intersection operates during PM rush notices a few obvious things, because of the influx of a dual left turn lane onto Spadina, Spadina gets overloaded from traffic from Bremner and traffic travelling south reguarly on Spadina thus runs into a situation where only 3 or 4 vehicles per lane can clear the intersection when facing the green. In essence, those who rat run, and use say Wellington to reach Simcoe, and then make a right onto Bremner are essentially butting the line on Spadina to reach the Gardiner.
The south side should have a pedestrian phase, and this is what I propose, the Bremner approach is redesignated to left turn, straight, right turn, this will be an inconvenient movement for drivers to reach the precious middle lane of Spadina, on top of that Spadina will not get as much as a load from left turning traffic.
Indeed, the split phase should be removed, and Bremner and Fort York should have a fully protected simultaneous left turn, after the simultaneous fully protected turn phase ends, a green ball should appear and a ped signal on both sides of the intersection should display a walk sign.
The real problem to this is if I recall correctly, Fort York has a very small left turn lane that only allows a couple of vehicles to queue (If I remember right).
What do you guys think, I'm no expert, and while I am a mature student of civil engineering, I have never taken any such courses in traffic engineering in my life, I have learned all the terms from observing intersections and independent research on the net.
