By Torontoist

Have questions about the TTC? Rocket Talk is a brand new regular Torontoist column, featuring TTC Chair Adam Giambrone and Director of Communications Brad Ross’s answers to Torontoist readers’ questions. Submit your questions to rockettalk@torontoist.com!

Photo by spotmaticfanatic from the Torontoist Flickr Pool.

Reader Brock Warner asks:

I live in Mimico, and head west to Humber College every weekday, and east to downtown at least a couple times a week. Why do the streetcars arrive bunched up in groups of 2 and 3 so often? I understand that delays happen, but it is becoming frustratingly frequent.

TTC Chair Adam Giambrone says:

We get this question a lot.
Service reliability—having buses, streetcars, and subways come as often as they are supposed to, and on a regular and predictable basis—is one of the most important parts of providing good quality transit. This is reasonably easy to achieve when the service is operating in its own private space—like subways in their own tunnel, or LRT in a dedicated right-of-way—and you have almost complete control over what goes on in that space.
However, when buses and streetcars have to operate on public roads, and compete for space with everything from private cars to courier trucks, they have almost no control over what goes on in that space, so it becomes much more difficult to ensure that the service will be regular and reliable. Often, buses or streetcars get delayed, causing a “gap” in service.
Once a bus or streetcar falls behind, the problem “snowballs” because more and more people end up waiting at the stops, and it takes longer for these bigger crowds to get on board, so the streetcar falls even further behind, and so on. The streetcars behind the delayed one catch up, the streetcars become bunched together and, when they finally arrive at the stop, they are in twos or threes.
Here’s an example of how even a few seconds here and there can make have a big impact on a busy route:
Say the buses on a given route run every 3 minutes apart. Bus A gets held up an extra 18 seconds at a stop with an unusually large group of people waiting. Then it gets stuck behind 2 cars making right/left turns and it takes 18 seconds more than normal to clear each intersection. Bus B—behind bus A—does not have these problems (it is lucky enough not to get stuck behind cars the large crowds were picked up by Bus A.) This means the bus A is now 30% (or 54 seconds) behind and, instead of 3 minutes between buses, Bus A is only about 2 minutes ahead of bus B. Presuming another bus is ahead of Bus A, it is now at least 4 minutes (instead of 3) behind that bus. If this continues a little more, bus A and Bus B bunch together, and the gap at the front grows.
This is a deterioration of service which frustrates all transit users. Here are the main reasons why it happens, and how the TTC is trying to improve the situation.

• Traffic congestion causes streetcars or buses to fall behind schedule, and so do blockages such as double-parking, road construction, or emergencies. The TTC is working to implement the Transit City Light Rail Plan which will create a network of exclusive rights-of-way for light rail so that the service won’t have to contend with congestion or obstructions and can keep moving quickly and reliably even when traffic on the road around it is not moving. With this, and other service improvement initiatives, the TTC will attract more people out of their cars and onto transit, and this will help reduce traffic congestion and the negatives that flow from it such as air pollution and collisions. In the meantime, the TTC and City are working together to put in place changes to traffic by-laws and regulations which will help reduce congestion in obvious problem areas.
• Traffic signals can cause streetcars and buses to fall behind schedule, especially when they just miss the green light and have to wait for a whole red light to move. The TTC and City of Toronto have installed transit signal priority—which gives buses and streetcars green lights faster and holds the green light until the bus or streetcar has made it through the intersection—at almost 350 intersections in Toronto, and plan to expand it to another 1,500 over the next three-to-four years. This will significantly reduce the delays which are caused by waiting at red lights.
• Big crowds of people all trying to get on a bus or streetcar at the same time—and all through the front door—can significantly delay the bus or streetcar. This happens at the end of the work day at a large employer, when a large store closes for the night, or a movie or sporting event lets out, or a busy intersecting bus or streetcar route has a lot of people transferring onto another route. The TTC is working on expanding its proof-of-payment system—which lets people board faster using any door—and is part of a larger initiative to introduce a “smartcard” automated fare collection system which also allow people to board quickly at any door and reduce delays which currently result from riders all “funnelling” through one door.
• A shortage of supervision can also cause vehicles to be delayed and get bunched up. Bus or streetcar operators don’t have the “bird’s eye” view that a supervisor does, so they can’t know when an incident has occurred on a route or where the other streetcars or buses are. Route supervisors have access to this information and can tell operators what’s going on and what they should do to provide the best possible service. The TTC is implementing transit-specific GPS monitoring on its services so that route supervision can be more effective, with hand-held units. There is also an increase in the number of route supervisors by 20, with a plan to get 40 more when funding will allow it.
• Routes that are carry very large volumes of people require very frequent service to accommodate the demand. With very frequent service, even relatively minor delays can cause bunching. Short turns are an old way of improving headways, and even though the TTC is trying to reduce the number of them needed, they’re unlikely to go away altogether anytime soon. Few people know why vehicles are short-turned, and are understandably miffed when it happens on their ride. Short-turning a vehicle, though, and plugging it back into the line to space things out better, is sometimes necessary to ensure overall service reliability. Going forward, the TTC will be purchasing larger light rail vehicles, with multiple doors, that can carry about twice the number of passengers that our current streetcars do. The larger capacity will allow the vehicles to be scheduled somewhat further apart, and this will also reduce the incidences of bunching and gapping.

There are other factors which affect the bunching-up of streetcars and buses, and the TTC is working on as many of them as possible, but I hope that this helps make this problem more understandable, and helps explain what the TTC is doing about it.