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Behind the scenes with MBTA data.

The COVID-19 pandemic obviously continues to have great impacts on MBTA ridership. In the past few weeks we have kept you updated on these pages, and we plan to keep updating the blog weekly as long as there is something to discuss. This post focuses on ridership on subway and bus during the last week; you can read previous posts here and here.

If you’re just looking for the total ridership by line and by station, you can download that data here (Last updated 4/14):

Validations by Line [csv]

Validations by Station [csv]

We would like to reiterate that Governor Baker has issued a stay-at-home order, non-essential business are closed, and we would implore our riders to respect this and stay at home whenever possible. In the Governor’s words: “Just because the T is open does not mean we think it’s a good idea to take the train downtown to meet up with friends.

By limiting the use of public transportation to essential activities, we will not only slow the spread of the virus – but we will better protect our health care workers, grocery store workers and others who are working every day to keep us safe.

Everyone is advised to stay at home and limit all unnecessary activities.”

Please see the continuously-updated page here for the latest updates on how the MBTA is responding to the pandemic: www.mbta.com/covid-19

The Data

Our usual ridership reporting includes factors to account for passengers who we do not observe through our automated equipment, and we usually wait at least a few weeks before reporting anything due to the delay in transferring data from our vehicles. We also conduct in-person counts to verify automated data and improve accuracy for our end of year reporting. 

We did not have time to do our normal analysis and reporting, so we had to focus on the best sources we have that were reasonably representative of the system. So we focused on two data sources for this post: Counts of validations at gated stations from the fare collection system and bus ridership estimates from automated passenger counters. Because these sources usually have extra processing and QA/QC done as noted in the previous paragraph, all ridership estimates in this post should be considered very preliminary and subject to change.

Rapid Transit

To examine ridership on the rapid transit system, we used validations (taps or ticket insertions) at the 64 gated stations in the MBTA system. This data came from the fare collection system and is not adjusted to account for passengers who enter the gates without interacting with the equipment (this can be children, fare evaders, or people who enter when the gates aren’t functioning).

We set up a special data transfer to gather the total validations by day, and then grouped them by station and by line. For stations where passengers can board multiple lines, we use a rough “split” factor to assign riders to each line (For example, at Park St, we estimate that 54% of people entering the gates are then going to board the Red Line, and 46% go on to board the Green Line).

Last week, ridership ended its drop at about the same time as non-essential businesses closed and has been largely steady since then. The below chart shows the validations per day for the last two weeks, including weekends. On the second axis, we show the percent of our baseline “normal” week this is. Note that for the baseline Saturday and Sunday comparison, we excluded the Orange Line data for the weekends of 2/1 and 2/15 when multiple stations were closed for track work and the gates on the remaining stations were left open on purpose. 

The validations per day for the last two weeks, including weekends

By the end of the week, the number of validations remained close to the same for three consecutive days, suggesting that indeed, travel had been minimized and was about 10-11% of “normal.” On weekends, validations had dropped less, but were still 14-16% of the average comparable weekend in February.

Bus

Overall bus ridership shows similar trends as gated stations, though the drop is less steep. After Tuesday, ridership became fairly steady, as while we estimate some change day-to-day, there is a moderate margin of error on all the estimates. Some of the challenges in the data are accounting for buses with lower samples of APCs, and accounting for additional trips that were added which were not part of the schedule programmed into the software on-board buses (“run-as-directed” trips). 

Ridership in the second half of last week remained steady at around 90,000 passenger trips per day. 

Bus ridership in March 2020

Here are the top 20 routes by ridership and their change from our baseline week. The geographic trend in ridership change is similar to previous weeks.

The top 20 routes by ridership and their change from our baseline week.

Ridership by Time of Day

With so many people who normally commute during peak hours staying home, the very nature of the “peak” has changed. We decided to look at how ridership has changed over the course of the day. This is not only interesting, but also helps inform MBTA operations so they can ensure we are scheduling enough service to maintain physical distance for essential passengers.

The following charts show validations at gated stations, sorted by line and grouped by half hour period, for an average weekday in our “baseline” week of February 24, 2020, and the same data for March 24 through March 27, 2020.

 Validations at gated stations, sorted by line and grouped by half hour period, for an average weekday in our “baseline” week of February 24, 2020

Validations at gated stations, sorted by line and grouped by half hour period, for an average weekday in the week of March 24, 2020

In the first image, showing “normal” ridership, we see significant, defined peaks on every line. Roughly 30,000 validations occurred during both the 8:00-8:30 AM period and the 5:00-5:30 PM period. We also see a smaller peak at around 3 PM when school gets out, especially on the Orange Line. You may notice the Green Line has more validations later in the day – this is because riders on the Green Line tend to live on the above-ground portion and work on the subway portion, so we capture fewer of the taps in the morning for regular commuters.

The second image from last week still shows two peak periods, but they are less defined and occur earlier than our usual peaks. In the morning we are seeing the most taps in the period from 7-7:30 AM, and nearly as many in the 6-6:30 AM period, while the 8-8:30 period has fewer validations. In the afternoon, we’re seeing a peak from 3-4:30 PM, rather than our usual peak at 5 PM. While we are not experts on health care, this seems to correspond with the traditional 3 PM and 7 PM shift change times at hospitals. Looking at the stations that are closest to major hospitals gives us a further clue. Here is the chart for March 24-27, selecting just Charles/MGH (in red), Bowdoin (blue) and Tufts Medical Center (orange):

Validation chart for March 24-27, selecting just Charles/MGH (in red), Bowdoin (blue) and Tufts Medical Center (orange)

While the MBTA is currently running a Saturday schedule, we have used this information to add additional service at times of higher demand in order to provide enough space for essential workers to ride and maintain physical distancing. We will continue collecting these data and using it to make service decisions as we continue our response to the crisis.