The Presto Card System and the TTC Mon, Jan 30. 2017
The Metrolinx stored-value payment system, Presto, has been used by a number of transit systems for many years, including Brampton, Burlington, Durham, GO Transit, Hamilton (HSR), Mississauga (MiWay), Oakville, Ottawa (OC Transpo), and York Region (YRT/Viva). Although there have been some significant glitches, the Presto system works well overall on those systems. I used Presto for years on Viva in Vaughan and really liked it.
Presto is about to rolled out to Toronto's TTC system, and unfortunately, the rollout is not going well, and will not go well on the current course.
How Presto Works
The Presto card has two main attributes:
- It is a stored-value system. That means that the actual value is stored on the card itself, unlike an Interac direct debit card or a credit card, where the value is managed by a remote computer system. The advantage to a stored-value card is that the transaction can be processed locally, without the delay of contacting a remote computer, and a reliable data connection is not required (useful when boarding a bus in a tunnel or underpass, or when a communications network is down). [For the geeks in the crowd, the Presto card uses a Mifare DESFire technology compatible with the ISO/IEC 14443 Type A standard, 13.56 MHz (the same frequency band used by NFC devices in cellphones and Interac/credit cards, but different from the RFID system used for most door access cards and dongles), with 4 kilobytes of data memory (if you want to compare this to your USB flash drive, that's 0.000004 GB, or about one typewritten page of text). Paper Presto cards for visitors will probably be similar to the paper passes used on other systems, which are similar to the plastic cards but have less memory, typically 64 bytes].
- It is a radio-frequency ID/near-field communication contactless system. This means that the card contains a tiny speck-sized computer, a small amount of flash memory, a radio circuit, and an antenna which goes around the perimeter of the card. When the card is held up to a reader, a radio signal from the reader provides enough energy to boot the card's computer, which then communicates with the reader to exchange information and, when necessary, to store revised information (such as a new balance) in the card's flash memory. Yes, it is amazing that all that can take place in the fraction of a second that you hold the card on the reader.
These attributes define the way the system works.
Loading Value Online
One of Presto's challenges comes when you want to load value on the card online -- through a web browser or your phone. Once you've gone to Presto's web site and performed the transaction, the Presto system has to get the additional value onto your card. Since the card readers throughout the system do not get in touch with a central server during a card tap, the only way to ensure that your card gets updated with the
added value is by sending an update to every vehicle or station in the entire system that there's a load-value transaction pending for your card. That means that thousands of readers from Ottawa to Hamilton have to store a list of every pending online-load transaction, and when you tap your card on any of the readers, they have to very quickly search through their stored list to see if they should add value to your card. After one of the readers loads the value onto your card, a message is sent back to the central servers, and the transaction is eventually removed from the queue on the all of the card readers. This is the reason that Metrolinx tells Presto users to allow 24 hours after an online load transaction before the value will be loaded onto their card
-- and in my personal experience, in rare cases it's several days longer.
The issue with this is that it doesn't scale very well. The volume of data that needs to be sent from the central servers to the card readers to manage online loading increases with the product of the number of reader locations and the number of people performing online card loads.
With a very small number of active TTC Presto users, the system isn't currently seeing anywhere near the load that it will need to carry a year from now. Many current TTC riders with Presto cards also use other payment methods such as tokens, because Presto cards aren't accepted at all locations yet -- including convenient unattended second entrances in many of the TTC stations. In addition, many Presto users have learned to avoid online load transactions, and load their cards in person at service counters or self-load machines.
You can see the impending challenge: when Metropasses subscriptions move from physical cards to Presto, there will be over 50,000 additional online updates per month. Hopefully, these transactions will be spread over a period of time and not dumped into the system all on one day, but in any case, these thousands of additional updates will strain a system that appears to have trouble with existing volumes.
Variations in the Use of the Presto System
There is significant variation in how transit systems use Presto cards. For example:
- GO Transit expects riders to tap on at the start of their trip and tap off at the end, and charge by the distance travelled (failing to tap off results in a penalty charge, plus fare to the end of the line).
- YRT/Viva provides 2 continuous hours of travel after you tap on to their system. Additional taps do not result in a deduction from your card (unless you press a button for a second-zone add-on for travel between the North and South parts of York region). This system provides certainty in the minds of the users, but it does leave room for some problems -- for example, if you tap on to a hour-long Viva trip from Markham to York University 90 minutes after you first tapped for the trip; your trip will finish after the 2h has expired, but tapping on to the Viva trip will not deduct a fare because you still have 30 minutes active on the previous fare; I wonder how fare enforcement works in this case? This system does have the benefit of allowing you to stop and buy milk on the way home from work, or duck out for lunch and get back to the office on a single fare.
- Some systems permit you to load passes on your Presto card, while others (such as GO) just stop charging you additional fares when you have hit a maximum pass-equivalent amount within a month or week.
Problems with the TTC's Implementation of the Presto System
The TTC's specific implementation of the Presto system has several significant pain points:
- TTC Presto fares continue to use the TTC one-continuous-trip transfer system, which permits you to transfer as many times as necessary for one continuous trip regardless of duration. This means that it's not permissible to stop to shop or have lunch during a trip. The challenge with integrating this approach with the Presto is that the system's software has to determine whether a tap on a second vehicle is a continuation of a trip (no additional fare charged) or a new trip (fare charged). This is complex to calculate when the original tap was on the other side of the city and the system is running perfectly, but it's impossible when weather delays, vehicle breakdowns, traffic problems, special events, or detours delay a portion of the trip. When using paper transfers, the rider could explain to the driver or collector why their transfer is older than expected, but this level of discretion does not exist in the Presto system. Solution: the TTC should switch to a time-based transfer system, allowing unlimited travel for 90 or 120 minutes per trip regardless of the number of vehicles used.
- The TTC's Presto readers do not display any information about the transaction taking place during a tap -- just whether it is Accepted or Declined. The rider is left in the dark about whether a vehicle transfer is charged as a second transaction or accepted as a transfer on the original fare. In addition, the user has no idea when value-load transactions take place, nor the current balance on their card. A rider who is assuming that transfer transactions are being processed correctly or that online loads are being stored on the card in a timely fashion can be easily stranded after their one grace transaction (a single negative-balance transaction is permitted, with a penalty charge). In
contrast, other systems (such as YRT/Viva) clearly display the transaction amount and card balance on every tap (although their poorly-lit screens are a lot harder to read than the TTC's bright colour screens). It has been argued that the ability to check one's balance and transaction history online mitigates the need for at-time-of-tap transaction and balance information, but this puts the onus on the rider to frequently login and check that the system is performing as expected. Solution: the TTC should display transaction, value-load, and balance information at every tap. At a minimum, there should be some indication of a low-balance state (less than 2 TTC fares remaining on card).
- The TTC's self-load machines are routinely out of order, especially
(according to a fare collector, to my surprise) around the end of each month. They look like they are fully online, but they fail to recognize an inserted Presto card and thus commence any transaction. Solution: this should be addressed by the contract with the Presto technology providers, and vendor performance penalties should be in place and enforced.
- The Toronto-York Spadina Subway Extension (TYSSE) project will require a new fare structure. Right now, over 2000 buses enter the York University campus every day, including Brampton Zum, YRT/Viva, GO, and TTC. When these buses are moved off-campus later this year, York University and Seneca@York students and staff will need to take a short subway ride to the new connection points north of campus. Paying a complete TTC fare on top of the Zum/YRT/Viva/GO fare for this privilege will in most cases double riders' transit costs. Solution: the system needs to provide a rebate of the TTC fare when tapping on to these other services, or better yet, Metrolinx should negotiate a multi-system fare that includes time-based travel on all interconnected systems.