Behind the scenes with MBTA data.

In this post, we investigate the occurrence of people traveling in groups using a single CharlieCard or CharlieTicket.

Occasionally, when people navigate transit in larger groups made up of family, friends, colleagues, etc., one rider will use their individual fare card to tap in and pay for the other people that they are traveling with. Both CharlieCards and CharlieTickets can be used by multiple different people to pay for fares at the same faregate or farebox.

Imagine a CharlieCard to be a wallet with two compartments: the first compartment holds a pass and the second compartment holds stored cash value. When a card with both a pass and stored value is tapped against a fare box or a fare gate, the first tap is processed by the pass compartment and the subsequent taps from other group members are processed by the stored value compartment. While both a CharlieCard and CharlieTicket can be used for pass-back, one advantage of using a CharlieCard is that up to four pass-back taps are tracked to provide transfer discounts. This feature is not available with CharlieTickets.

Pass-back Overview

Group travel occurs for various different reasons: e.g., leisure trips, school field trips, during sports events, or general tourist travel. By studying pass-back situations, we can identify group travel patterns and bus routes and Rapid Transit stations at which group travel occurs. We performed this analysis in order to identify where people travel in groups and how many people relied on this functionality. The results will inform how we can best serve these trips when this functionality is eliminated as part of our new fare collection system (AFC 2.0). As part of AFC 2.0 we plan to allow all-door boarding and move to a proof of payment fare verification system. This will require everyone to have their own fare card or other method of payment (smartphone, etc.). 

Outline

In the following sections, we will provide some context and data about pass-back use on first a yearly, and then monthly, basis. We first took a broad look at 2017 pass-back use before diving more specifically into October 2017. We’ll explain how the findings of our analysis allowed us to ascertain answers to the following questions:

  • When and where is pass-back used the most?
  • Who uses pass-back?
  • How many people relied on the one fare card when traveling in groups?

To conduct this analysis, we queried our ODX database to select all transactions during October 2017, for all users except employees and contractors. Multiple taps at the same location on the same card or ticket within 10 minutes of each other (excluding the initial tap) were identified and tagged as pass-back taps. We then calculated pass-back rate separately for bus routes and Rapid Transit stations. This analysis helped us identify the share of all taps used for pass-back and the share of all CharlieCards/Tickets used for pass-back.

But first, let’s look at 2017…

Pass-back in the Year 2017

In the year 2017, 1.48% of all taps were pass-back taps. Ninety-three percent of these taps were on Cards/Tickets with stored value and 7% were on Cards/Tickets with a pass. The second and the third quarter accounted for 59% of the total pass-back rate for the year. The below chart shows the month-to-month use of pass-back across bus and Rapid Transit.

We observed that July was the month with the highest pass-back rate of 2.12% and that pass-back was more likely to occur during the warmer months compared to colder ones. This is probably due to higher numbers of tourists using the MBTA during the spring and summer for events like baseball games and festivals. 

The above chart shows the month-to-month use of stored value and pass-back on stored value across bus and Rapid Transit. You can see that while more stored value is used during the summer, there is also a higher rate of pass-back use.

This observation helped us identify the months during which group travel occurs most frequently. With the confirmation that the spring and summer have higher likelihoods of people navigating our system together in groups, we can improve our operations and customer service geared towards group travel.

In the following sections, we’ll perform a deeper dive into the data gleaned from our October 2017 pass-back analysis. 

When and Where is Pass-back Used the Most?

Time

When looking at specific days of the week, we divided the system’s service time into five categories, as listed below. 

Category Time Time Period
1 03:00 - 06:59 Sunrise and Early AM
2 07:00 - 08:59 AM Peak
3 09:00 - 15:59 Midday Base and Midday School
4 16:00 - 18:39 PM Peak
5 18:30 - 02:59 Evening, Late Evening, and Night

By splitting service hours into these five categories, we were able to identify which specific times of day had the highest number of pass-backs. The bar graph below shows the pass-back rate per day and per time category. 

From the above chart, we can see that on weekdays the pass-back rate was higher between 9 AM and 03:59 PM (time period 3) in comparison to other times of day. Additionally, the pass-back rate was higher during weekends than on weekdays. 

It is apparent that people are more likely to travel in groups on the weekends than weekdays, perhaps for social and/or leisure outings. 

Location

In order to identify specific locations where higher rates of pass-back is occurring in the system, we examined buses at the route level and Rapid Transit at the station level. The following two charts show the top routes and stations ranked by the pass-back rate. 

Route 435 (Liberty Tree Mall - Central Square, Lynn or Neptune Towers via Peabody Square) had the highest pass-back rate of 2.78%.

Riverside station had the highest pass-back rate of 4.87%. The top three Rapid Transit stations with the highest pass-back rates are Riverside, Museum of Fine Arts, and Science Park. 

From the above analysis, we noticed that for bus routes, the highest pass-back rates were in the North Shore (Lynn and Salem) and at shopping centers. For rail stations, the highest pass-back rates were at locations known for attracting tourists, short-term visitors, and schools. 

The high usage on bus routes in Lynn and Salem might indicate a need for more CharlieCard distribution in these areas. We are currently working to establish community partnerships to give people more access to blank CharlieCards. 

Who Used Pass-back?

There were about 0.7 million Charlie cards used by Adult users in the month of October 2017 and 12.57% of them were used for pass-back. This was high compared to other fare media (for Adult users). 

We then looked at the number of rides the adult users took in the month of October 2017 and the percentage of trips that used pass-back. The below chart suggests that infrequent adult riders or people who take one to five rides in a month are the ones who most often used pass-back.

People who traveled on the rapid transit or bus network two times in a month, used pass-back on 10.75% of their trips. This led us to identify the percentage of cards using pass-back for each adult rider category. 

Type of Riders Adult User Type Category (Rides) Percentage of Cards Using Pass-back
Infrequent 1-5 rides per month 12.91%
Occasional 6-20 rides per month 16.32%
Frequent 20+ rides per month 9.31%

We categorized adult user ridership based on the number of rides they took during the month of October 2017 and found that 12.91% of infrequent rider CharlieCards were used for pass-back while more than 9% of frequent rider CharlieCards were used for pass-back. 

The above chart suggests that the percentage of trips taken using pass-back was high for infrequent riders, but the above table suggests the occasional and frequent rider cards were also used for pass-back.

The analysis in the above section will help us prepare for AFC 2.0. Infrequent-use cards are likely using pass-back more often because the people they are traveling with do not have cards. In AFC 2.0, we will make cards more available by having them available at vending machines, but also will provide the capability to pay with a device such as a smartphone, which should lessen the need for multiple people to share one type of payment media.

When Someone Uses Pass-back, How Many Other People Do They Tap In?

(How many people relied on the one fare card when traveling in groups?)

We analyzed the number of times people performed a pass-back and how many other people were tapped in with one card. We found that in the 87% of trips where pass-back occurred, one other person was tapped in.

We concluded that people are more likely to travel with one other person than with a whole group. This pattern will inform the way we think about possible group-specific fare products in the future; we should keep in mind that “groups” are often no larger than two riders. 

Conclusion

Our comprehensive analysis of the pass-back data had many interesting takeaways. The study revealed that the pass-back rate is generally higher during the warmer months and at rapid transit stations used by tourists and people attending sporting events. The high usage of pass-back on bus routes on the North Shore indicates that we need to improve CharlieCard distribution in these areas now. 

Approximately 13% of Adult riders with CharlieCards performed a pass-back. And pass-back is used more often by infrequent riders i.e., the percentage of trips taken by infrequent riders using pass-back is higher compared to frequent riders. In advance of AFC 2.0, this analysis is helping us prioritize locations for fare vending machines and consider fare products for infrequent riders.  

This type of analysis of existing AFC system data is very useful as we consider the changes that will occur with AFC 2.0. It is informing the development of the policies that will support the new fare collection system and ensure that it serves the needs of all types of riders.