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Behind the scenes with MBTA data.

Panel used to determine at what point people will stop boarding a vehicle due to crowding.

On May 24th, 2016, MassDOT and the MBTA hosted an interactive panel to discuss the 25-year strategic vision for MBTA investments: the Focus 40 Kick-Off Event. The event focused on the current state of the system, and how the MBTA can best take into account the technological advancement, demographic shifts, climate change, and transportation needs of the future in order to best serve the needs of the Boston region in 2040. As part of this event, OPMI presented a poster (shown below) focusing on capacity of the MBTA system to serve its customers. 

Diagram showing proportion of men and women unwilling to board a crowded transit vehicle

  Infographic designed by Green Nong

Perception and acceptance of crowding

A key component of capacity is how readily riders accept crowded conditions. Different people perceive and react to crowding differently, and their willingness to board a crowded vehicle affects its functional capacity. These functional limits are different from safety considerations regarding the maximum capacity of a vehicle. In order to provide enough capacity, we need to determine the “break points” in acceptance of crowding among actual MBTA riders.

The data comes from a survey to gather rider input on the agency´s service standards as part of the revision process of the Service Delivery Policy. The survey was available online and was open between June 18th and July 31st of 2015. Results were weighted by mode use and minority status.

To assess crowding acceptance, respondents were asked to look at six different levels of crowding and select the point at which they would stop attempting to board the vehicle. As shown on the first graph in the infographic above, the collected data suggests the crowding critical level to be at 4.36 ppsm (people per square meter) with a cumulative percentage of 61% for men and 69% for women refusing to board at that level of crowding. The infographic above highlights gender differences, and results show that in general, women are less tolerant of highly congested spaces when riding the MBTA compared to men. In addition, there is a significant percentage of both men (19%) and women (13%) that responded they would always attempt to board, no matter the level of crowding.

Attendees at the Focus40 kick-off event participated in an interactive version of the survey question: they reported their own level of unacceptable crowding, when they would refuse to board the vehicle. We then confirmed their reported level by re-enacting that level of crowding in a taped-off square meter. As in the survey responses, most people would stop boarding at crowding level of about four people per square meter, and these reports were confirmed with the physical crowding exercise, indicating that the graphical representations created an accurate perception of the crowding level. 

 Visitors to the crowding poster stand in a taped-off square-meter box

Other comfort concerns

To get at mode variations in comfort expectations, we also asked respondents, “How important is it for you to get a seat on any part of your most frequent trip?” This question only includes data on users’ most frequent trip by mode. Results show that commuter rail users are the most concerned about getting a seat, followed by those using the bus, and then those using rapid transit. In other words, the data suggests that across the three presented modes, commuter rail users are the most worried about finding an available seat when riding. 

These results were also confirmed by attendees at the Focus40 event, many of whom reported having different standards and expectations for different modes, with the vast majority indicating that getting a seat on the Commuter Rail is very important because the trips tend to be longer, and people don’t generally get off the train and free up seats mid-way through the trip. Despite the indication that open seats are important, there is a competing comfort priority: many people would prefer to stand rather than take the middle seat in a row of three seats. Attendees also indicated that on a bus, standing feels less safe than it does on rapid transit vehicles; so even though the length of time spent standing may be the same on both modes, riders tend to value bus seats more highly than subway seats.