Just How “Peaky” are (Pre-Pandemic) Peaks in Demand?

In our review of the impacts of the COVID-19 pandemic on ridership, we showed the following charts that display average entries at gated stations over the day. This shows us how ridership during the pandemic has been not only lower in volume, but also less focused on the traditional peak times around 8 AM and 5 PM on weekdays.

While the “traditional” pattern is clearly very peaky, the contrast becomes even more stark if you start to dig into the data more granularly. Here is a chart of average entries on weekdays (all lines) in Fall 2019, sorted into 5-minute buckets (compared to the 30-minute buckets above).

In the five-minute period from 5:10 to 5:15 PM, the T averaged just over 6,200 taps at gated stations in Fall 2019. But, just a few minutes later from 5:25-5:30, the T averaged 4,998 taps, and a few minutes earlier, from 4:55-5:00, we averaged 4,679 taps per weekday.

Here is a chart showing the same time period, focusing just on the downtown stations on the Red Line: South Station, Downtown Crossing and Park Street:

From 4:55-5:00 PM, these three stations see an average of 840 taps per weekday. But just a few minutes later from 5:05-5:10, we average 1,240 taps. Some of these passengers entering at these stations are headed for the Green, Orange or Silver Lines, but other passengers are also transferring behind the gate from these lines to the Red Line. Fortunately, ODX estimates these boardings, and we have them already aggregated here by 15 minute buckets: 

Counting transfers and non-interaction, ODX estimates that over 4,000 people board the three core stations on the Red Line in the time period from 5:15-5:30 PM. By 6-6:15 PM, this has dropped to about 2,800 passengers.

If three trains pass through these stations in that time period and we assume passengers are traveling in both directions equally, that’s over 600 passengers (most of an entire train!) who are boarding each train during the busiest time. When you add in additional passengers who enter at busy workplaces like Kendall, Central, and Broadway, not to mention any passengers traveling across downtown, then it’s no wonder that crowding reaches extreme levels at this time of the day. With trains at capacity, there is very little margin for error: When there is even just a slight delay, or a particularly busy day of ridership, passengers are at crush capacity, are left behind, and ultimately have a bad experience. For some passengers, the crowding levels even when things are working perfectly is unacceptable and forces them to choose other options (We examined this with some focus groups and surveys in a blog post here).

Mass transit’s particular advantage over other transportation modes is its ability to move large numbers of people from a wide area into a particular place at the same time without them needing to park a vehicle. But when transit is over capacity, we have a “tragedy of the commons” situation where the service works significantly less well. And adding peak capacity is very expensive, and sometimes impossible. 

One of the potentially positive things to come from the pandemic is the likelihood of increased flexibility in work hours for many people who were previously part of the peak-of-the-peak crush load. Additionally, transit agencies throughout the country have realized (or emphasized) that their essential ridership – those who have continued to ride transit throughout the pandemic – are often riding outside of peak hours. Importantly, these non-work trips are also the types of trips that transit needs to be competitive for in order to reduce car ownership among inner core neighborhoods. 

If traditional 9-5 passengers are more flexible in when they leave work, and transit agencies are able to provide more service off-peak and in neighborhoods to better serve non-work trips, we could eventually reach a scenario where ridership is similar (or even higher) than pre-pandemic, but less concentrated on the peak-of-the-peak. Consider the following chart, which shows hypothetical Red Line boardings during the PM peak, if they were more spread out:

To create this chart, a “capacity” of 3400 boardings per 15 minutes was applied to the data from Fall 2019 shown above. This amount of demand, given peak-level service, would create full, but not overcrowded trains in each direction. Additional boardings above this capacity were distributed among the other time periods between 3 and 7:30 PM in the same proportion as the existing ridership. To keep things simple, 54 boardings were eliminated entirely. In this purely illustrative scenario, we can see that nearly the exact same number of passengers board the Red Line between 3 and 7:30 pm, but they are simply less concentrated at the busiest time. Add in some additional ridership off-peak and on weekends, and you could see a scenario with even higher ridership than before. 

Time PeriodFall 2019 Avg.Hypothetical Future Scenario
3:00 PM1,3971,469
3:15 PM1,6051,687
3:30 PM1,7001,787
3:45 PM1,6741,761
4:00 PM2,0852,193
4:15 PM2,5302,661
4:30 PM2,7442,885
4:45 PM3,0253,180
5:00 PM3,6853,400
5:15 PM4,4603,400
5:30 PM3,7383,400
5:45 PM3,2853,400
6:00 PM2,8673,014
6:15 PM2,6152,750
6:30 PM2,3252,445
6:45 PM1,8191,913
7:00 PM1,6041,687
7:15 PM1,3641,434

The MBTA would not, and likely could not enforce a particular capacity on boardings. But, this thought experiment illustrates that if future flexibility in passengers’ schedules allowed more passengers to board outside of the busiest time, the MBTA could carry just as many passengers as pre-pandemic. Just as importantly, this scenario would likely provide more timely (due to reducing the likelihood of being “left behind”), comfortable trips for all passengers, and more reliable service overall.