MBTA Rapid Transit Ridership
by Amy Trinh
The Massachusetts Bay Transportation Authority (MBTA), more commonly known as the T, is a division of the Massachusetts Department of Transportation. It provides subway, bus, rail, and ferry service to locations in Massachusetts and to some neighboring states. Its rapid transit system consists of 5 lines: the Red Line, the Orange Line, the Blue Line, the Silver Line, and the Green Line. The Green Line has 4 branches: the B, C, D, and E branches; and the Red Line has 2 branches: the Braintree and Ashmont branches.
The main dataset used throughout this app is a collection of data about the gated entries on each day that the MBTA is open for service. The gated entry data is collected through their fare system whenever a passenger taps or inserts their CharlieCard or Charlie Ticket. The number of entries is collected every 30 minutes at each station and identified by the route or line and by the station name. Other identifiers such as ID codes and numbers are reported in the data set as well.
You can click here to view the MBTA Rapid Transit data set!Rapid Transit Ridership
Here you can explore ridership trends through time between 2017 and 2021 by moving the date range slider.
Yearly Ridership
Below is a plot that shows the total number of gated entries in 2017, 2018, 2019, 2020, and in part of 2021. There is a slight downward trend in each subsequent year between 2017 and 2019 and a huge drop in ridership in 2020.
*Note: Total ridership for 2021 only includes data until March 31, 2021. Total ridership for all other years shown are from the beginning of January to the end of December.
Station Ridership
Here you can select a time range and an MBTA station you want to view. The ridership, or gated entries, is plotted against time.
Covid Cases in MA vs. Ridership
The COVID-19 pandemic has influenced the daily lives of everyone in numerous ways. With many workplaces requiring employees to work from home, with many schools making the switch to remote learning, and with many recreational activities limited to prevent the spread of the virus, I wanted to see how MBTA ridership was impacted.
Analysis
The Student's t-test is a statistical test that is used to determine the significance between differences in groups. It is a form of hypothesis testing where the null hypothesis states that the groups being looked at are essentially equal and where the alternative hypothesis states the opposite.
Independent t-tests evaluate the difference in means between two unrelated groups. They can be used to compare the ridership between two different years because the years are unrelated and just represent a grouping.
2019 vs. 2020
The t-test produced a result with a p-value of 2.2e-16 which means that if the null hypothesis were true, the likelihood of getting the results would roughly be smaller than a fraction of a percent. This means that we can reject the null hypothesis and conclude the alternative hypothesis that the difference in means of the two group is significantly different.
Now, we can just stop here and claim that ridership between 2019 and 2020 are different. But is this difference common between years, or is there potentially an external factor impacting ridership that leads to this huge difference in means?
2018 vs. 2019
To figure out whether the difference in ridership actually matters, we can compare ridership in the year 2019 to the year before. The t-test produced a result with a p-value of 0.3822 which indicates that if the null hypothesis were true, there is roughly a 38% chance that we would see the same differences in means as we do. Because of this high p-value, we can accept the null hypothesis.
Just looking at the figure showing total ridership by year can quickly show that ridership in 2020 was different than in years prior, and the t-test just further confirms what can be inferred visually. Total ridership slightly declined year after year, but it is unlikely that ridership dropped drastically from 2019 to 2020 just by chance. Decreased ridership was likely due to the restrictions put in place as a result of the COVID-19 pandemic.