[Apologies to those of you who are pining for even more articles on the Queen car. They will show up in due course. I have been diverted onto Dufferin by recent events.]

Service on the 29 Dufferin bus has been a burning issue for decades. Buses run in packs, they arrive full of passengers, and the advertised service bears little resemblance to what riders see on the street.

Recently, this was the subject of an article in The Grid by David Topping. In it, the TTC’s Brad Ross trots out many of the usual explanations of why service is unreliable. In deference to Brad (who is really a nice guy), I don’t want to spend an article eviscerating his comments line by line. I will leave readers to contemplate information in this and following articles and make up their minds.

What riders see is “headways”, the time between vehicles, as well as the degree of variation in that time. If the TTC says a bus will appear every 5 minutes, and the service manages to achieve this, more or less, most of the time, then a rider will consider this “reliable”. Even on a wider advertised headway, if buses appear at roughly the expected interval, riders know what to expect.

However, if the headways vary widely from the scheduled value, this makes a service unreliable and riders must, at a minimum, build in additional travel time to account for the possibility of a long wait. Moreover, at the end of the wait, they may be faced with a jammed bus they cannot board. There might be another one (or two) right behind, but that makes no difference to the length of the wait, and those buses might not be going to the rider’s destination. Providing frequent service “on average” is not what riders want to see.

In this article, I will review the actual headways provided by the Dufferin bus at various locations during the month of March 2012. Although this is technically “winter” (most of it), 2012 was a balmy year and the route operated without the kind of severe weather delays we have seen in 2013.

In future articles I will turn to running times and the effects of congestion on the route’s ability to maintain regular service. I will also look at a few days’ operation in detail to see exactly what was going on.

The information used for this analysis comes from the TTC’s GPS-based vehicle tracking system which reports the position of every vehicle every 20 seconds allowing fine-grained resolution of movements at any location.

Service Levels

When looking at the actual service, it is important to know what the schedule claimed the service should be. Route 29 Dufferin was among the routes whose service was cut in February 2012 as a budgetary measure. The loading standards were changed to allow more riders per bus, on average, during various periods of operation.

The following table shows the pre- and post-cut headways, and also includes notes about service improvements since March 2012.

29_201203_Service

Observed Headways

In the charts linked below, each set contains eight pages with a similar layout. In all cases, time reads across the X-axis and length of headway reads up the Y-axis.

The first five contain data for the weekdays subdivided by weeks within the month. March 2012 had no statutory holidays (Easter fell in April in 2012) and so the only variation comes in the first short week which has only two days. Weeks 2-to-5 have five days each.

The sixth chart contains all of the weekday data on one page to show a “cloud” of points and the general distribution of data for all of the weekdays in the month.

The seventh and eighth charts contain data for Saturdays and Sundays respectively. These days are broken out because of their different traffic and service patterns.

Trend lines on all charts (except the sixth) show the best fit of each day’s data. These generally lie at about the value of the scheduled headway except when service is erratic and infrequent.

Summaries of Observed Headways

The first set of charts show all of the data with one point plotted for each bus passing a location. Another way of looking at the same information is to summarize it by time period and by the value of the headway.

In the summary charts, the number of buses at each headway (1 minute, 2 minutes, etc.) for a period such as the AM peak are summed, and these values are displayed as percentages. The TTC aims to have 65% of its bus service within 3 minutes of the scheduled headway. If this actually happens, a chart will have a peak at the scheduled value and will quickly drop off on either side. However, in some cases, the values are spread out over a wider range. In others, the most common values seen are 1-2 minutes (bunched service) with a wide range of other values some of which are far from the scheduled headway.

Northbound Service

29_201203_NB_King_Headways

29_201203_NB_Bloor_Headways

29_201203_NB_Lawrence_Headways

Although the Dufferin bus has a branch that runs through Exhibition Place during certain hours from Dufferin east to the Princes Gates, the main service originates at Dufferin Loop at the Exhibition’s western gate. King Street is a few blocks north and is the first major cross-street. Service at this point should be fairly well-spaced because most buses have just left the terminal.

Many of the data points are clustered around the trend lines, at least within a value of ±3 minutes which is the TTC’s goal for service punctuality. Because of the low scheduled headways, this means that many “punctual” vehicles are running very close to the one in front. In other words, they left the terminal in a bunch.

By the time we get to Bloor and the connection to the subway (2.4 km north of King), the weekday data points are roughly in the same pattern as at King.

At Lawrence (a further 6km north), part of the peak service has short turned at Tycos (half-way between Eglinton and Lawrence). The data points are more widely spread especially in the PM peak. The wider scheduled peak headway on the northern section of the route simply compounds the general unevenness of peak period values, well beyond the TTC’s 6-minute target band. This is an example of how a metric that looked only at certain parts of the route (say, at Bloor), or which averaged various points together, may mask problems on selected parts of a route.

On weekends, especially in the evenings, the scheduled headways are longer, but the distribution of actual headways is very wide, much beyond the six-minute range. The situation is bad at both King and Bloor, but by Lawrence headways bear little resemblance to the advertised service.

The headway summaries tell the same story but present the data in a different manner.

29_201203_NB_King_Headway_Summary

Northbound at King, the weekday service headways lie mainly in the ±3 minute band, but the data spread out as the day wears on, especially in the evening.

Saturday mornings fit the target pattern, but by Saturday afternoon service is running with headways below the scheduled value (1 or 2 minutes) being the most common, and the rest of the service spread out over a range up to 10 minutes. Saturday early evenings continue this problem. By late evening, the headways range fairly evenly over a range from 0 to 15 minutes when the schedule calls for 11’00”.

Sunday early mornings should be a period when it is easy to maintain a scheduled headway, but even then, there is a wide range of headway values. The range tightens up a bit in the late morning, but there are still many buses running close together on a scheduled 5’00” headway. Sunday evenings show headways over a wide range of values.

The common factor here is that even near the route’s southern terminus, the service is not operating on a reliable headway much of the time. The only possible explanation is that buses are not leaving on time because they have only travelled a few uncongested blocks when they reach King Street.

29_201203_NB_Bloor_Headway_Summary

By the time the service reaches Bloor, some of the unevenness seen at King has worsened. One minute headways are the most common value seen for most of the time on weekdays, and this shows that service has become even more bunched as it travelled north from King. In the late evening, service is spread out more than the six-minute range around the scheduled 7’15” headway.

On Saturdays, as at King, the service moves further away from the target headway as the day goes on. By the afternoon, over 25% of the buses arriving northbound are on headways of 1 minute (this bar actually represents values from 0’30” to 1’30”), and service is badly bunched. This continues into the early evening. By late evening, as at King, the headways range widely with much of the service outside of the target six-minute band.

Sundays continue the pattern seen at King Street with a wide variation in headways especially in the evening. It is very difficult to believe that this is the result of traffic congestion, but rather the complete absence of any attempt to dispatch service at headways resembling those on the timetable.

Southbound Service



29_201203_SB_Transit_Road_Headways

29_201203_SB_Eglinton_Headways

29_201203_SB_Bloor_Headways

Southbound headways are shown first at Transit Road and Wilson, just outside of the line’s northern terminal. The next point is Eglinton, 4km to the south, and then Bloor, another 4km down the line.

At Transit Road, weekday service shows a similar pattern to that at King Street northbound with most vehicles clustering around the trend line. As at King, the scheduled headway is short enough that “punctual” service can actually be operating closely behind its leader. A greater scatter of headway values shows up here in the PM peak just as it did northbound at King.

By the time we reach Eglinton southbound, the service is a bit more spread out (compare the width of the weekday “clouds”) than it was at Transit Road, but some of the longer headways seen in the PM peak at the north end of the line have vanished.

At Bloor, the values have spread out further, and headways above 10 minutes are common throughout the day with no real indication of a peak period effect at all.

Weekend values show a lower service quality with a greater spread of values and bunching is still common.

29_201203_SB_Transit_Road_Headway_Summary

As with the northbound service, what we see at Transit Road southbound is fairly well-behaved headways until the PM peak, but then the values spread out. However, there is not the same degree of bunching as the service leaves its northern terminus.

Weekends show the same pattern of spread out headway values in the evening as we saw northbound.

29_201203_SB_Bloor_Headway_Summary

At Bloor southbound, buses are near the end of their inbound trips. During the AM peak, very short headways are most common showing the bunching that has occurred enroute from Wilson Station. This continues through the day and even into late evening when a considerable amount of service is running close together on a nominally 7’15” headway.

Saturday service is fairly well-behaved until the afternoon when short headways dominate showing badly bunched service. This continues into the evening when headways well beyond the six minute band are common.

Sunday service starts off with widely scattered headways and never reaches a point where values lie mainly in the target band. By Sunday afternoon, bunching is common, and in the evening headways are over a wide range of values as on Saturday.

Summary

Headway reliability on the Dufferin bus is very poor and this occurs even at times when there should be little interference in service from traffic conditions. On weekends evenings, service is unpredictable because the headways lie over so wide a range and many buses are running in groups of two or three.

The observed data suggest that for some operating periods, nobody is “minding the store” and no attempt is made to hold vehicles to the target headways.