Roads: Traffic Signals

[reaperexpress]

In Ontario, there is a delay of about 3± seconds, when the traffic signals turn red in one direction before the other direction turns green (or the left turn phase). During that delay, the other direction transit vehicles should be given their priority. At the end of those 3± seconds, the transit signal should end and the other direction turns green (or the left turn phase begins). If the transit vehicle is still in the intersection, the left turn vehicles can still edge into the intersection and wait for the transit vehicle to clear before attempting to complete their left turn.

The all-red clearance interval exists to provide enough time for vehicles to clear the intersection if they are unable to stop on amber. Violating it represents a major safety hazard.

That said, there is some logical basis for two of your suggestions: that streetcars can get a green earlier than left turns, and that left turns can get a green soon thereafter.

On an intersection with two-way traffic, the centre of the intersection will become clear before the edges. So with a median ROW, transit could technically get a green slightly before general traffic.

But in Ontario we calculate the all-red based on clearing the entire intersection before any subsequent phases start. In contrast, some jurisdictions such as the Netherlands calculate clearances based on the conflicting phase that follows. So if a particular movement would become clear a second earlier than another, it would get a green a second earlier. And if the stop bar is set back quite far for a subsequent movement (which it often is in NL due to side-of-road bicycle paths), then that movement would get a green a little earlier to compensate. I think this is called two-dimensional clearance timing but I can't find much documentation on it.

For example let's look at St Clair and Caledonia, a pretty typical median ROW example and calculate the clearances for cars separately from transit. Based on Ontario Traffic Manual Book 12 section 3.6, the clearance for all-way red is
t = 3.6 (W +l)/V
where W is the width of the intersection in metres, l is the length of the design vehicle (6 metres for a passenger car), V is the speed limit in km/h (50 on Caledonia) and 3.6 is the conversion factor from km/h to m/s.
From the stopbar to the far side of the crosswalk along Caledonia is 35.9m, which means that the time to clear the entire intersection is 3.02 seconds from start of amber. Clearances should always be rounded up, but this could possibly be rounded down to 3 on a judgement call.
From the stopbar to the far side of the streetcar ROW is 20.2m, which means that the time to clear the streetcar ROW is 1.88 seconds from start of amber. That would round to a 2 second all-red.

So technically streetcars could get a 1 second head start without violating all-red clearances if we used two-dimensional clearance calculations.

Because of the geometry of the interactions between the streetcars and left turns, you could probably get away without much all-red clearance between the end of the inserted transit phase and the start of the left turn phase. As you noted, it is not a safety issue, since people will not accelerate into the side of a streetcar already blocking their way. But there isn't much benefit to starting the green early, since the left turners will still be unable to proceed until the streetcar is out of their way, regardless of the colour of the light. A 6 second clearance might be a bit much for a 15 metre CLRV, but once we start running 30 metre Flexities on St Clair, even a 6 second clearance would likely have the green for left turns starting before the streetcar is out of the way. The best source of time saving would be to allow extremely short minimum greens for streetcars- maybe 4 seconds. The green would continue only until the moment the front of the streetcar crosses the stopbar, from which point the streetcar's clearance time would be consistent enough to begin the left turn exactly at the right moment (about 2 seconds before the streetcar is out of the way).

The bottom line is that while there is some logical basis for your concept, the real-life numbers simply don't work out for it to be a strategy on its own. The efficiencies you note might be able to save a second or two, but that falls well short of the dozen or so seconds it takes a streetcar driver to react to a green light and travel far enough through the intersection for left turns to proceed. In the end, what you are suggesting is basically an inserted phase with maybe a second or two saved through improved efficiency. These are valid comments regarding increasing intersection efficiency, but it doesn't change the fact that the City needs to approve the use of inserted or rotated phases to prioritize streetcars over left turns.

 

[Napoleon]

Note: there are no red traffic signals arrows in Ontario.

I really wish they had red arrows in Ontario. I think they would be especially useful in decluttering intersections like Queen's Quay. Having to put a "Not turn on Red" sign up is a much subtler visual cue than a red arrow.

Odd in the video that the woman is driving with flip-flops on. That's always been described as a no-no to me.

 

[LNahid2000]

How many Ontario motorists don't follow the rules in this video?

Note: there are no red traffic signals arrows in Ontario.

lol I rarely see motorists stop before the line at stop signs and red lights. They don't seem to understand that the line is there for a reason.

 

[W. K. Lis]

I've seen cars stop PAST the stop line and wonder why the traffic signals don't change, even after the pedestrian countdown signals get to zero. If there is no car or even a bicycle over those black lines behind the stop line, the traffic signals don't change.

 

[Johnny Au]

I've seen cars stop PAST the stop line and wonder why the traffic signals don't change, even after the pedestrian countdown signals get to zero. If there is no car or even a bicycle over those black lines behind the stop line, the traffic signals don't change.

Which intersection was this photo taken?

 

[reaperexpress]

I've seen cars stop PAST the stop line and wonder why the traffic signals don't change, even after the pedestrian countdown signals get to zero. If there is no car or even a bicycle over those black lines behind the stop line, the traffic signals don't change.

If only. That picture is likely not from Ontario - the loop placement and line painting looks wrong.

Here, the loop usually extends well past the stopbar and into the crosswalk. Rather than penalizing drivers for stopping past the stopbar, this placement actually reinforces that dangerous and inconsiderate behaviour.

Ontario Traffic Manual Book 12 section 5.9 states:
"The recommended placement of presence loops requires maximum setbacks of 4.5 m from the intersecting through edge of pavement."

So the only way a typical 5 metre car would not be detected is if it is fully in the path of intersecting vehicle traffic. That sort of makes sense in lanes where right turns on red are permitted and there is a desire to detect those vehicles for some reason. But in any other situation, it represents a shocking disregard to pedestrian safety.

Consider the following requirements from Ontario Traffic Manual Book 11 section 3.8:
- Crosswalks must be set back from the intersection by at least 0.6 metres,
- Crosswalks must be at least 2.5 metres wide,
- The stop bar must be set back exactly 1 metre from the crosswalk.

So in the absolute tightest scenario with a crosswalk, the stopbar is 4.1 metres from the intersection. But in suburban intersections, the crosswalk is usually set back by a lot more than 0.6 metres, and in urban intersections it's usually a lot more than 2.5 metres wide.

Basically this policy indicates that it is more important to save an incompetent motorist from backing up after stopping too far forward or waiting till another vehicle shows up, than it is to keep crosswalks clear of stopped vehicles. This is actually plausible, since a motorist that sits indefinitely at a red signal as a result of stopping too far forward might complain to the signal operations people, but a pedestrian forced into traffic the road by a blocked crosswalk will not. If they do complain, it will go to traffic enforcement or something, not the people operating or installing signal equipment.

If we did place loops as per the photo above, I think people would quickly get in the habit of stopping properly. Waiting ages at a signal is the sort of thing people remember, and many people do try to figure out where they will and won't be detected.

Placing detection loops only in the place people are actually supposed to stop is an example of enforcement-by-design, something I find to be disappointingly rare in Ontario.

 

[reaperexpress]

When I was visiting Quebec, some intersections had the left turn phase AFTER the regular green phase. In Ontario, we have the left turn phase BEFORE the regular green phase.

There's no rule against lagging left turns in Ontario, and there are a few examples in town such as at Spadina & Lakeshore and at Lakeshore & Ellis. But there's a lot more to this topic than you might think.

So much so that my response ended up morphing into a full fledged blog post.

The bottom line is that lagging left turn phases are more complicated, which is probably why all the examples in Toronto I can think of are at intersections controlled by the SCOOT adaptive system.

 

[Duck]

People have no idea what a stop bar is and also have no idea how to turn into the correct lane when there are two or more lanes in a given direction. Those are my two most hated violations I see on a regular basis. The turning into the correct lane thing is more than just an annoyance - it's a huge efficiency killer, because let's say it's 2 lanes in each direction at both roads at an intersection, but just one left turn lane... cars coming from that left turn lane should turn into the closer lane on the road they're turning in to, so cars coming from the opposite direction wanting to turn right on red can legally do so and take the other lane. In reality, when you wait to turn right in this scenario you have no idea if the idiots coming from the left turn lane will obey this or not and careen into you.

 

[Filip]

People have no idea what a stop bar is and also have no idea how to turn into the correct lane when there are two or more lanes in a given direction. Those are my two most hated violations I see on a regular basis. The turning into the correct lane thing is more than just an annoyance - it's a huge efficiency killer, because let's say it's 2 lanes in each direction at both roads at an intersection, but just one left turn lane... cars coming from that left turn lane should turn into the closer lane on the road they're turning in to, so cars coming from the opposite direction wanting to turn right on red can legally do so and take the other lane. In reality, when you wait to turn right in this scenario you have no idea if the idiots coming from the left turn lane will obey this or not and careen into you.

Who is responsible for a collision if one happens? Would it be the one who doesn't know how to make a left turn properly?

 

[Woodbridge_Heights]

People have no idea what a stop bar is and also have no idea how to turn into the correct lane when there are two or more lanes in a given direction. Those are my two most hated violations I see on a regular basis. The turning into the correct lane thing is more than just an annoyance - it's a huge efficiency killer, because let's say it's 2 lanes in each direction at both roads at an intersection, but just one left turn lane... cars coming from that left turn lane should turn into the closer lane on the road they're turning in to, so cars coming from the opposite direction wanting to turn right on red can legally do so and take the other lane. In reality, when you wait to turn right in this scenario you have no idea if the idiots coming from the left turn lane will obey this or not and careen into you.

This goes both ways actually. An road in my neighbourhood narrows down from 2 lanes to 1 shortly after an intersection (less than 100m). I am constantly waiting while making a left turn as drivers make their right turns into the far left lane (which is the lane that continues on after the narrowring). As you described both vehicles should be able to perform their manovoure, left turning vehicle into the left lane, right turning vehicle into the right lane. Then sort out a merge on the narrowing of the road. Happens elsewhere too not just that intersection.

Who is responsible for a collision if one happens? Would it be the one who doesn't know how to make a left turn properly?

Not sure, I feel like somewhere in my driver training that the vehicle making the right hand turn (all things being equal) has the right of way as that is a simpler move and has fewer conflict points with other traffic. Also was taught in situations of unknown right of way to yield in the following order: Traffic coming from your left, then traffic coming from in front of you, and finally traffic coming from your left

 

[Napoleon]

Not sure, I feel like somewhere in my driver training that the vehicle making the right hand turn (all things being equal) has the right of way as that is a simpler move and has fewer conflict points with other traffic. Also was taught in situations of unknown right of way to yield in the following order: Traffic coming from your left, then traffic coming from in front of you, and finally traffic coming from your left

If a driver is turning right on red, it is his responsibility to yield to all other traffic that has the right of way.

 

[Woodbridge_Heights]

If a driver is turning right on red, it is his responsibility to yield to all other traffic that has the right of way.

Yes ... and no. A vehicle turning left yields to all traffic in the opposite direction. The scenario noted above two vehicles, one turning right, one turning left, both into the same direction of travel, and having the light turn red. The vehicle making the left turn would have to yield not the one turning right, however if both vehicles can manage to make their turns into the proper lanes without overrunning into the others lane than both can make their turns nearly simultaneously. If it were a 1 lane road though the left turning vehicle would yield to the right turning vehicle.

 

[DSC]

City of Toronto Media Relations has issued the following:

==========================================


News Release


January 14, 2016


City issues RFP for smart traffic signals


As part of ongoing efforts to modernize its traffic signals, the City of Toronto has recently issued a Request for Proposal (RFP) for the provision of a new, adaptive ‘smart signal’ system. Smart traffic signals adjust in realtime to traffic volumes on the roadway, meaning that signals can allocate green time in a way that helps minimize congestion.


The City has operated about 350 smart signals since the early 1990s, but the current system has reached the end of its service life. The City is hopeful that international leaders in the area of smart signals will respond to this RFP, giving Toronto a chance to see and adopt the best possible technology.


This RFP calls for a 20-intersection pilot beginning in late 2016/early 2017, with the option to expand the program to up to 500 signals over the next five years if the pilot is successful.


The RFP can be accessed via the City’s call documents website at: https://wx.toronto.ca/inter/pmmd/calls.nsf/0/02995F58D53BF10D85257F34006A0553?OpenDocument.


This news release is also available on the City's wesbite: http://ow.ly/X4Sam

 

[reaperexpress]

From the RFP summary:

"The Solution should be capable of providing Transit Signal Priority (TSP) function and capable of future central emergency vehicle pre-emption."

That would be an improvement over SCOOT, since we currently don't use TSP with it.
From Page 12 of the RFP:

Toronto does not have any SCOOT intersections with the built-in TSP feature enabled. This feature was tested at one intersection and the TTC rejected the outcome because it is not possible to emulate the TSP to the same level being provided on MTSS.

There's a pretty big range of TSP quality with adaptive systems. On some systems such as SCOOT, TSP is a bit of an afterthought, so it's severely throttled to avoid messing up the "optimized" timings. But apparently others such as SPOT-Utopia, use adaptiveness to actually improve the performance of TSP:

SPOT-Utopia is a traffic signal control program for a city or smaller area, developed originally at the Polytechnic University of Turin, and later commercialized by its current owner, Mizar Automazione SpA of Turin. It was first applied in Turin, which continues to be the program’s largest installation and testbed for innovations. Unlike other adaptive control programs, public transport priority was part of the motivation behind SPOT-Utopia. [...]
Predictions about public transport vehicle arrivals are made using a longer time horizon, about 5 minutes. Using a Kalman filter, the public transport travel time profile is constantly updated so that predicted arrival time will reflect recent conditions. [...] Predicting and optimizing offers several advantages to public transport. Individual public transport vehicle arrivals can be predicted, and predicted far enough in advance that signals can be readied for their arrival, rather than face a last-second request to change. Green waves can be developed for public transport vehicles over a short time horizon, updated frequently to account for unpredictable dwell time and signal delay times.

From section 10 of this paper

 

[ottbike]

Traffic improvements coming to West Queen West Triangle, including a new traffic signal at Queen/Beaconsfield:

http://www.anabailao.com/wqw_triangle_traffic_management_plan_update_february_2016

• Abell Street (once open), to operate in a "1 way South" direction: approved and awaiting installation;
• Lisgar Street (Queen St. West to Sudbury Street), to operate in a "1 way North" direction: approved and awaiting installation;
• Removal of parking spaces adjacent to driveway entrances on Sudbury Street to improve sightlines for motorists entering/exiting underground parking lots: approved and installed in fall 2015;
• "All-way stop control" (sign) on Sudbury Street, at Lisgar Street: installed in December 2015 - white pavement markings to be painted this summer;
• "All-way stop control" (sign) on Sudbury Street, at Abell Street: approved and awaiting installation;
• Speed humps on Dovercourt Road (Queen to Sudbury) with 30 km/h speed limit: approved and awaiting installation;
• Speed humps on Subdury Street (Queen to Dovercourt) with 30 km/h speed limit: residents polled and resident petition received, awaiting approval at Community Council;
• "Pay-and-Display" parking on the west side of Abell Street: approved and awaiting installation;
• Loading zone on the west side Abell Street: approved and awaiting installation;
• Accessible parking space on the west side of Abell Street: approved and awaiting installation; and
• Installation of a "traffic control signal" (light) on Queen St. West, at Beaconsfield Ave: installation feasibility study forthcoming from City staff.