The Problem of Scheduled Service Irregularity

In a series of articles, I reviewed the quality of service on many bus routes during a period, the lull in traffic and demand during the pandemic, when it should have been relatively easy for the TTC to operate reliable service.

A consistent factor on almost every route was that buses are running in bunches with wide gaps between them. Those gaps translate to crowded buses followed by lightly-used ones, and riders rightly complain about long waits and an uncertain arrival of the next group of vehicles.

The TTC argues that service is not really that bad because they have a large number of unscheduled extras (aka “RAD” or “Run As Directed”) buses that do not show up in vehicle tracking records. Leaving aside the obvious need to track all service, not just the scheduled buses, this does not explain why buses run so close together so much of the time. These are tracked vehicles that have a schedule that should keep them apart.

Or so one might think.

TTC Service Standards include provisions for headway quality (the reliability of spacing between vehicles), but this is fairly generous, and it is never reported on as an official metric of service quality.

However, another problem is that on some routes, the service is actually scheduled to come at uneven headways. This arises from three issues:

  • Some routes with more than one branch have different frequencies on each branch. This makes it impossible to “blend” service with, for example, alternating “A” and “B” destinations.
  • In response to the pandemic, the TTC quickly adapted schedules by cancelling all express buses, and selectively cancelling individual runs as a “quick fix” to avoid complete schedule rewrites across the system. Where local trips were cancelled, this created gaps in the scheduled service.
  • On many routes, notably those that formerly had express service, the TTC scheduled “trippers” to supplement the basic service. However, these trippers were generally not scheduled on a blended basis leaving riders with scheduled, but erratic service.

In some cases, the September and October schedules corrected some of these problems, but many persist. This article looks at a number of routes where the summer (August) schedules had uneven headways to see what, if anything, has changed by mid-October. (The most recent set of schedules went into effect on October 11, 2020.)

All of the data presented here were taken from the TTC’s schedules as they are published in GTFS (General Transit File Specification) format for use by travel planning apps. This almost exactly matches information on the TTC’s online schedule pages.

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TTC Bus Service Frequency and Reliability in 2020 (Part IV)

The four east-west corridors detailed in this article share a common characteristic in their schedule changes between the pre-covid winter schedules and the spring-summer versions. The only change has been to remove the 9xx express service without any update to the underlying local services.

In some cases, this represents a substantial cut in the total service provided on portions of the route where roughly half of the “winter” service operated as express trips. Some of these cuts are substantially greater than the TTC’s oft-cited 80-85% level of pre-covid service, and this illustrates an ongoing problem with reporting stats on an average basis that hides the fine detail.

These are long routes where service might not even be well-spaced leaving the terminals, and headways become much worse along the way. The problems cannot be attributed to “congestion” in times of relatively light traffic, and there is clearly no attempt at headway management. In turn, the uneven headways cause crowding well beyond what all-day averages might suggest.

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