Improving Our Slow Zone Tracker

Improving Our Slow Zone Tracker

Our slow zone tracker has been a huge success—not only has it been a valuable tool for T riders to validate their experiences, but it has also been useful for MBTA accountability. It provided valuable insight into slow zones before and after the Orange Line shutdown, and more recently we have been tracking the worsening slow zones on the Red Line. We’ve also been referenced a few times:

• The Boston Globe - It’s not just the Orange Line: Poor maintenance is slowing whole T system

• Boston Herald - Orange Line is slower, more speed restrictions in place than before shutdown

• Reddit - It’s not all doom and gloom, today is the first day that the orange line is faster than before the shutdown

We’re able to build these tools and make a difference because of support from the public. If you would like to make a donation, you can do so here.

After eight months of tracking slow zones, we’ve decided to make some changes to our calculation methodology. These changes are going live today, and we’re excited to share them with you. What follows is an in-depth description of what we changed. 

TL;DR

1. For the Total Slow Time page: We now determine each slow zone’s delay on a per day basis. We previously used the average delay over the entire duration. The graph is noisier, but it more accurately reflects changes over time.

2. We updated our algorithm for determining slow zones by adding the criterion that a segment must have at least 4 days of delayed trips.

3. For the Line Segments page: The delay time displayed for a given slow zone is now the median delay rather than the mean. 

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Change 1: Daily totals determination for the line graph

We changed how we calculate daily slow zone totals (graph).

Previously:

For each day that a slow zone exists, add the slow zone’s mean delay. This is defined as mean(daily median trip time - baseline) over the duration of the slow zone.

Now:

For each day that a slow zone exists, add the slowzone’s delay from that particular day only. This is defined as simply (daily median trip time - baseline). If there is no data for a particular day due to shuttling e.g., we use the last available data so that they don’t falsely appear to be fixed.

Why is this better?

It shows the state of the system on a given date more accurately. Previously, if a long-running slow zone was improving or deteriorating, it would be difficult to notice since the value shown over the course of the slow zone was constant. Furthermore, each new day’s data could affect the line graph for previous days because it could change a slow zone’s mean. Now, we show each day independently to better reflect changes as they are made. 

For example, consider a slow zone with these delays:

Date	1/17/23	1/18/23	1/19/23	1/20/23	1/21/23	1/22/23
Delay	3 minutes	3 minutes	1 minute	1 minute	1 minute	1 minute

Previously, we would show a flat mean across all 6 days, and that mean would change gradually from 3 minutes to 1.6 minutes with each new day that passes. Now, each day will be represented on the graph by how much delay there was that day. This means we will be able to see the improvement immediately on 1/19/23.

This is how our total slow zones graph looked before the change:

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Slow zones graph before the change.

This is what it looks like now:

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Slow zones graph before the change.

The new graph is noisier, but it more accurately represents the system’s real delay on each date.

Change 2: Slow Zone Determination

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We changed what we define as a slow zone. The definition of a slow zone depends on what we call a delayed day.

• A delayed day defines whether the travel time between two adjacent stations is delayed on a given day

• A delayed day between two stations is determined when its trip time is 10% greater than the baseline triptime - this has not changed. What has changed is what we call a slow zone.

• Previously any span of time during which there were 2 or more days of delayed trips within 4 days of each other was a slow zone. There is now an additional criterion: This span must contain at least 4 days of delayed trips.

Change 3: Line Segments Delay time

This change affects the line segments page (this graph).

The delay displayed on each segment is now the median delay over the period rather than the mean delay. 

Media Statement: TransitMatters Demands Answers For Beleaguered Red Line Riders; The MBTA Must Regain Trust

BOSTON, October 24, 2022 — MBTA Red Line riders put up with a lot - broken escalators, crumbling staircases, and too-frequent derailments. But lately, anyone riding the rails between Alewife and Ashmont or Braintree has almost certainly noticed that their ride is also quite a bit slower than it should be. The TransitMatters Slow Zone Tracker shows that a round trip on the Red Line is almost 15 minutes longer than it should be, with no sign of improvement. In a Boston Herald article on October 19th, MBTA spokesman Joe Pesaturo said that “The T’s Engineering and Maintenance Division is working to schedule an appropriate time to perform rail replacement activities." This brief statement is insufficient to address the concerns and anxieties of riders and municipalities that rely on the Red Line. The MBTA must come forward with a complete and specific description of the deficiencies on the Red Line, and be fully transparent about what it will take to fix them and whether the T has the resources to do the job.

Unfortunately, this opaque statement continues a troubling pattern. Whether it was the announcement on the MBTA website, quickly retracted, of a severe north-side Red Line diversion of indefinite length, or the "late completion of overnight work" causing shuttle buses to run during the morning peak hours just last week, the MBTA continues to be secretive and unclear regarding the condition of the Red Line and the work that needs to be done. TransitMatters strongly believes that the MBTA must do three things as soon as possible, and prior to any further Red Line (or any other rapid transit line) disruptions or diversions, to remedy the lack of clarity and help repair rider trust.

• Give advance notice of closures and diversions, and provide high-quality alternatives. The MBTA must provide at least three months of notice to municipalities and community stakeholders of closures and diversions on rapid transit lines, to ensure that plans can be made to accomodate diversion routes and provide high-quality alternate accommodations to riders. Those major stakeholders include Massachusetts General Hospital, UMass Boston, Harvard University, MIT, and every business in Kendall Square and the Seaport and Financial Districts whose customers and employees depend on Red Line access.  The MBTA should also reroute feeder buses to active rapid transit stations, and provide additional supplemental service on affected routes, including Commuter Rail. The MBTA should also provide meaningful fare mitigation and reduction during any large service disruption.

• Be clear about the work being performed and the condition of the infrastructure, before, during, and after the diversion. Before any diversion on a rapid transit line, the MBTA must give a clear statement of the work to be performed, and the ways in which the repairs will benefit safety and service. During the diversion, the Authority must provide regular updates on the work and be transparent about any delays or incidents. After the diversion, the MBTA must be clear about what work was completed, and when, if ever, service will improve. There must not be a repeat of the Orange Line shutdown, with conflicting statements, ever-shifting schedules, and slower service.

• Perform work overnight or on weekends, with early closures rather than full shutdowns. Full shutdowns are harmful to the system’s most vulnerable riders, and they are harmful to the economy.  The more work that the MBTA can do at night and on weekends with early closures and late openings, the better it is for riders and for everyone in Greater Boston. The MBTA should do what it can to increase its maintenance workforce, invest in permanent staff, and invest in maintenance equipment to increase Maintenance of Way productivity and effectiveness. The best shutdown is the one that doesn't happen.

TransitMatters believes that it's possible to make necessary safety and capital improvements while also minimizing the negative impact on riders. This is national and international best practice. More importantly, the T must develop the skills and workforce to do important work without shutting down whole lines. The alternative is a system that fails its riders at a time when rider confidence is at an ebb, and fails the region at a time when it needs a high-functioning transit system to support a recovering economy. 

For media inquiries, please e-mail media@transitmatters.org. 

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Media Statement: Orange Line Shutdown/Building A Better T 2022

BOSTON, August 3, 2022 — The Orange Line is an essential part of the MBTA system; it carries over 100,000 riders a day. Today’s announcement of a 30-day shutdown is a dramatic example of the urgency of improving service on the subway system. Going forward, the MBTA must commit to giving riders more notice. The short notice of this announcement shows a lack of respect for riders. The quality of the T’s communications to riders throughout this effort, as well as the quality of its mitigation efforts, will be major tests for the agency. As the MBTA plans to shut down this critical piece of transportation infrastructure on short notice for a month, we need the Authority, municipalities, and other partners to take an all-hands-on-deck approach and coordinate efforts to deliver effective and usable transportation alternatives for 100,000 T riders who will be disrupted by this initiative.

We are concerned that replacement shuttle buses have not functioned well during past diversions. Too often they were stuck in traffic, hopelessly delayed, and woefully insufficient to replace rail transit service. The MBTA and affected municipalities must act quickly to establish and enforce busways and protected bikeways along the routes used by shuttle buses and nearby existing surface transit routes that will receive diverted passengers, such as the 39 bus and the E Branch of the Green Line. This is an opportunity to show that quick-build bus lanes are feasible and can make a meaningful impact on travel times. To reduce costs from installation and removal, these lanes should be operational and enforced 24/7 for the duration of the shutdown. We urge careful coordination with municipal partners like BTD and BPD, as well as the MBTA Transit Police to ensure reliable service.

We’re pleased to hear that the MBTA will have commuter rail trains stop at Orange Line stations along the corridor including additional trains at Oak Grove and Forest Hills.  Fares from these stations should be waived for the duration of the diversion to ensure riders without a CharlieCard can access the service. Service should also be increased to stations along the route of the 34 Bus, such as Readville and Hyde Park. Many riders of the 34 transfer to Orange Line service at Forest Hills, and improved CR service to Southwest Boston is crucial to reducing pressure on the shuttle service. The T should also reduce fares on all Commuter Rail lines during the diversion to mitigate the increase in traffic caused by Orange Line riders switching to vehicles. Additionally, the MBTA should reassign Orange Line dispatchers to boost service on the Red and Blue lines, as well as boost service levels and capacity on the Green Line.

Finally, the MBTA needs to restore rider confidence by clearly communicating the benefits of this shutdown. Riders deserve a firm commitment from the MBTA that Orange Line service will significantly improve after this unprecedented diversion. The T must demonstrate that it can accomplish this shutdown within the strict 30-day period, and that it has in place strong oversight controls that were lacking during the recent Blue Line shutdown experience. Riders have put up with years-long slow zones, teething problems with new vehicles, and diversions with no appreciable impact on service. The MBTA must clearly communicate the benefits of this shutdown to riders and unveil a line with better travel times, more reliable service, and improved rider experience.

For media inquiries, please e-mail media@transitmatters.org. 

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