Why Do Streetcars Bunch Up?

Over at torontoist, Adam Giambrone responds to a question about bunched service outbound from Mimico on the Lake Shore with a collection of the usual lame TTC excuses about irregular service.

This is getting tiresome, and it is distressing to see the TTC Chair spouting so much of the party line from TTC management.  The reasons for irregular service, according to Giambrone, are:

  • Bunching caused by minor variations in the time spent at stops and traffic lights.  This applies to frequent routes where the headway (as cited by Giambrone) is fairly close to the variation in delay times.  The last time I looked, the best scheduled service on Lake Shore is every 8’40” on Saturday afternoons, rather worse at other times including peak periods.  Minor delays at stops do not account for bunching.
  • Traffic congestion.  Yes we have heard this before.  The point, as we have seen in many of my analyses of route operations, is that congestion is manageable, and bunching should only occur when there is an actual blockage of service.  See below.
  • Traffic signal delays.  Yes, signals are being changed to give priority to transit vehicles, but this has already been done on much of the Queen route.  Major intersections, where traffic engineers feel that transit priority could be counter-productive by its effect on cross-street traffic, run on their regular cycle.
  • Surge loads.  Yes, they happen, but they don’t explain routine bunching.  Moreover, on Queen, the line uses all-door loading at major stops.
  • A shortage of supervision.  See “traffic congestion” above.  The TTC feels that if it can just put a small army of route supervisors in the field with better technology to let them know where the cars actually are (see Next Bus display at Spadina Station when it works), they can manage the service better.  As some comments in the Torontoist thread point out, there is a big problem with operators leaving terminals more or less when they feel like it causing ragged service, and little seems to be done to manage the gaps and bunches out of the service.  This happens on many routes.
  • Short turns, larger vehicles, more service.  This bullet in Giambrone’s presentation is, to say the least, unclear.  We know that busy routes have delays and need short turns, although changes in the management style for the 501 eliminate most of the need for this tactic (a point completely missed in the article).  Larger vehicles will help provided that the total capacity of the route is also increased.  Queen has suffered for decades with the effect of a reduced number of cars providing allegedly equivalent capacity.  Between cases where short cars are running in place of long ones (and they get late because they can’t handle the demand) and the larger impact on waiting times of missing cars, the change to wider headways has been a disaster for riding on the line.  There is no indication that the TTC understands this problem.

There are three fundamental problems with service on Queen and on Lake Shore (where the original reader comment arose):

  • The Long Branch 507 should never have been amalgamated with 501 Queen.  The route west of the Humber River has a large amount of local demand, but the decline in service quantity and reliability of the merged route has never been acknowledged.  The TTC just does not understand that service is important on the outer parts of lines, not just at Yonge Street.
  • The amount of service on Queen is insufficient to provide a reliable headway and capacity for demand.  The TTC may point to declining ridership over the years, but this is not reflected on other parallel routes like King or Dundas.  The irregular service drives away riders.
  • Route supervision leaves a great deal to be desired.  For clarity I don’t just mean the guys standing on the street corners making notes on their clipboards, but the whole strategy of how a line and its operators are scheduled and managed.  The TTC is working on this, but changes are slow to come.

I have begun detailed examination of Queen route operating records for December 2008 and January 2009, and will be publishing results from this work here soon.

43 thoughts on “Why Do Streetcars Bunch Up?

  1. Maybe a mistake was made when the TTC discontinued MU operation way back when in 1977. Bringing it back might possibly be a solution.

    Steve: Only if they run lots of trains. We have already seen what moving from 50ft to 75ft cars did to Queen Street because the TTC managed the line just as they did when there were 50ft cars every few minutes. That doesn’t work on wider headways.

    When there were trains, it was rare that they stayed coupled for the entire peak period as they were always scheduled so that one stayed in service and one ran in after the peak. Typically the trains were broken so that one car could be short turned.


  2. Regarding Robert Wightman’s post on April 11 at 3.58 p.m., there are some factual errors regarding Lansdowne. I don’t like to beat a dead horse but facts are facts. Firstly, there are NO bike lanes … only sharrows which are not bike lanes but a reminder that cyclists are entitled to use the road (as they are entitled to use any road in the city).

    Secondly Lansdowne was NEVER 2 lanes of traffic in both directions but one lane in each direction with parking on both sides, thereby providing a buffer for pedestrians on both sides of the road. In the old setup, during rush hours, there would be 2 lanes of traffic in the most-heavily trafficked direction, with parking on that side of the street prohibited during that time.

    Now, on the east side, the buffer of parked cars has been permanently removed… which means that pedestrians are walking on a very narrow strip of sidewalk right next to a busy lane of traffic. Oh, and the travelling lanes have been made wider… which means that cars are moving faster than they ever were before. The setup is certainly better for cars… but not for pedestrians on the east side…. and given the speed of the cars, many of the cyclists end up using the sidewalks as well.


Comments are closed.