When I started the analysis of operations on various routes, I requested data for a number of suburban lines as well as the downtown streetcar routes. Up until now, I have only published material on 29 Dufferin, but it’s worthwhile getting some of the other data out in view before it is completely stale.
The data in this series come from December 2006, but the conditions on Finch have not changed too much in the interim. The service is not as complete a mess as we have seen on some of the major streetcar routes, but it is far from perfect. It’s worthwhile looking at how a frequent bus route operates in conditions that should be generally favourable to transit service.
As I have done before, I will start with Christmas Day 2006 because this shows the basics including the route’s behaviour when there is no excessive passenger demand or traffic congestion. For contrast, I will also present a weekday Friday, December 1, 2006.
Christmas Day, 2006
For those who are unfamiliar with these analyses, I refer you to the first series on the King Car. Briefly, there are three types of chart here:
- The Service Chart is based on a standard method of analysing railway operations dating to the late 19th century. The horizontal axis is time, and the vertical axis is location. Each line plots the movement of a vehicle back and forth on the route. The slope of the line is roughly proportional to the vehicle’s speed (see notes below). The spacing of the lines indicates the relative position of vehicles. Both directions of operation appear on the same chart, but once you are used to the format, it is relatively easy to concentrate on only one direction’s information. This layout makes it easy to see bunching of vehicles that persists beyond a terminus and continues into future trips.
- The Headway charts are, in effect, horizontal slices through the Service charts at specific locations. Each page of these charts gives a different location on the route and shows the spacing of vehicles at that location.
- The Link Times charts (not included for December 25 as they are only of interest in spotting traffic congestion) show the times individual vehicles take to get from one point to another on a route. Where these times are unchanging over the course of the day, vehicle progress is unimpeded by traffic congestion or excessive dwell times at busy stops.
All of this is prone to errors introduced in the data by the TTC’s vehicle monitoring system, CIS. Two problems affect this route:
- Near terminals, resolution of vehicle location is imprecise. Some vehicles may not register their arrival until they are about to leave, while others may appear to leave well before they actually do. On the large loop at the east end of 39 Finch, the exact location of the vehicle may not be accurately reported. To correct for this, the entire loop at Neilson is treated as a single location so that all buses are “there” regardless of exactly where within the loop CIS says they are. Headways at the terminals may not be correctly reported, but near the terminals, they are accurate.
- CIS uses a combination of odometer readings and electronic signposts to locate a vehicle. When a bus passes a signpost, the system corrects the vehicle location to match, and this can make a bus seem to move backward in space if the odometer is reading high. The data analysis routines I have written filter out most of this, but can cause vehicles to appear immobile for the time between the calculated arrival at a signpost and the time it actually reports this.
The Service Chart shows what we would expect to see for a holiday day. The service is fairly well-behaved running back and forth from Finch Station to Neilson Road. Even so, some variation in speed and in vehicle spacing is evident.
When we look at the headways, we see a pattern familiar from other routes. Page 9 of the eastbound chart shows the data at Willowdale Ave (between Yonge and Bayview). This is far enough away from Finch Station that terminal effects do not muddy the data. Although the headway is nominally six minutes, the actual headway lies in a wide band particularly in the morning and evening (when the headway widens to nine minutes). The range of headways considerably exceed the TTC’s own target of a 3-minute band, and many riders will encounter headways much wider than the advertised schedule.
This pattern continues at various points eastward along the route. Note that data shown for the terminal, Neilson Road, reflect the time vehicles arrived in the general area of th terminal, not exactly at Finch and Neilson itself.
Westbound headways starting at Tapscott (page 2) show the same pattern as we see at the west end of the line. Headways lie across a band of values exceeding the +/- 3 minute TTC standard.
Friday, December 1, 2006
Weekday service in December 2006 was somewhat different than today:
- AM peak service consisted of four branches on 6’00” headways: local services from Finch Stn. to Seneca College and to McCowan, plus express services to McCowan and to Neilson.
- Midday, all service ran to Neilson on a 3’00” headway.
- PM peak service had four branches: locals to McCowan and to Birchmount each on a 7’00” headway, and expresses to McCowan and to Neilson on an 11’00” headway. This meant that service to Neilson was much worse in the PM peak than at any other time of the day.
- Evening service was every 4’00” to Neilson dropping to 8’00” in the late evening.
Today (June 2008 schedules) the service is:
- AM peak on the same four branches, but each on a 5’15” headway.
- Midday all service runs to Neilson, but half as express, on a combined 2’30” headway.
- PM peak service has only three branches: the McCowan and Birchmount locals each are on 6’30” headways, while the Neilson express runs every 6’00”.
I will refrain from pointing out what a great candidate this route would be for some “higher order” transit service as that’s not the point of this thread.
The Service Chart shows the very dense service on this route, and if you look closely, you can see the expresses passing the locals during the peak period. The service spacing is not ideal at the end of the AM peak with two gaps opening up westbound to Finch Station between 9 and 10 am. However, there are so many buses on Finch that even a “wide” gap is comparable to a typical day on the Queen car.
By the afternoon peak, gaps start to appear again as well as some delays eastbound between Highway 404 and Victoria Park. As we will see in a later post, this does not happen every day. The weather on December 1 was heavy rain, and there may have been some overflow congestion from the highway.
Particularly noticeable is the widely spaced service to Neilson Road. Although this is scheduled at a 12-minute headway, the actual service is much more scattered as we will see in the headway charts in more detail.
Things settle down in the evening, but service spacing is still irregular.
The headway charts show the variations much more dramatically. Note that the first and last pages, corresponding to the terminals, have to be taken with a grain of salt because CIS does not reliably report departure times. Therefore, the charts for Tapscott and Willowdale (near Neilson and Finch Station respectively) are more reliable.
For December 1, the westbound headways from Neilson are appallingly bad in the PM peak, and we will see this pattern through the month. Although the service is supposed to run every 12 minutes, many buses are on headways of 18 minutes or more, and there is a gap of over half an hour.
At McCowan, the short turn service has merged in, but there are still gaps over 10 minutes throughout the day all the way over to Finch Station.
The return service eastbound is a little better. At Willowdale, most of the headways lie within the band of 0 to 6 minutes and therefore fit the TTC’s “on time” standard. However, as we continue east on the route, just as with the streetcar lines downtown, the short gaps get shorter while the wide ones get longer and gaps of 10 minutes are common. Beyond McCowan, the service to Neilson reminds me of the Queen car at Long Branch with pairs of buses and wide gaps.
I believe that what we are seeing here is the result of applying a laissez-faire attitude to a route that has lots of service on paper. There is no need to manage it because for most of the route, another bus will be along any moment. Service at the outer end is left to fend for itself. As we will see in the whole-month reviews, this situation is common to weekday operations, not the result of a single day’s foul-ups.
I should mention that I cannot explicitly identify the express trips from the CIS data. During periods when the Neilsons all run express, one can assume that these are express trips. However, it is impossible to definitively identify the McCowan locals and expresses.
The Link Time charts are interesting because they are so boring.
Again a caveat about terminals: Because the terminal departures are not always correctly reported, the link time the next time point I have chosen may vary. This typically shows up as spikes well above the prevailing level caused by some of the layover time being included in the departing trip time, and in wide variations in link times approaching a terminal such as Finch Station. (It would be nice to quantify congestion problems there, but the CIS data is not at a level of detail and accuracy allowing me to do this.)
Westbound, the link times show little of the variation we saw on Queen Street, and what we do see fits into the classical peak periods rather than the off-peak. For example, there is a slight rise in times from Seneca College to Leslie in the PM peak, but only by one or two minutes over the all-day values.
Eastbound, the link times don’t vary much except from Seneca College to Victoria Park in the PM peak. This corresponds to the congestion we saw in the Service Chart earlier. Other than this, the link times have little variation.
This is a good example of a route with very frequent service and little traffic congestion compared with ohter parts of the system we have looked at in this series. Nonetheless, service does bunch, and the one part of the route with scheduled wide headways suffers from the randomness of the frequent service projected into a branch where this causes wide variations. The lesson here is that special care is needed for routes where a comparatively infrequent branch is part of a much more frequent whole.
In the case of Finch East, the issue is moot to the degree that the 2008 schedule no longer has the planned infrequent service to Neilson during the PM peak.
In the next installment, I will turn to full month charts of headways and link times.