Analyzing the Recovery of the NYC Subway during COVID-19
We recently had the opportunity to provide data analysis in support of a New York Times article about the recovery of the Subway. More specifically, we did an analysis of “percent of usual” ridership by station for October 2020 to get an idea of where we are still seeing depressed numbers, and where things are getting back to normal. In this post, we’ll provide some supporting tables, charts, and maps for the analysis presented in the NYT, for those who want to go a bit deeper. Naturally, the data and code are also available for anyone who would like to reproduce or build on our analysis.
First, take a look at the article:
The article refers to “percent of usual” ridership in several places which was our attempt to come up with a normalized measurement for comparing the recovery of individual stations, boroughs, and the system as a whole. It’s important to understand how we calculated the “usual” ridership which we compared October ridership to.
What is usual, anyway?
For our analysis, “usual” was the average monthly ridership for a given station in 2019. We add up all of the subway entries for a given station for the entire year and divide by 12. Why an average? In earlier iterations of this analysis we would compare a station/month to the same station/month during the previous year, but this led to some anomalies as there were stations with skewed ridership due to construction and other abnormal events. Using an average gives us a more consistent and reliable denominator for calculating the percentage.
“Even as Manhattan stations remain eerily empty, a surge of commuters in other boroughs has pushed overall ridership to 30 percent of normal levels.”
What are the numbers behind this 30% figure? 45.1 million / 143.0 million = .3155 (systemwide entries in October 2020 / average monthly entries in 2019)
We can use the same math to calculate the percent of usual for each borough:
We can see that though Manhattan has the largest numbers, percentage-wise it is the only borough that is below the citywide average (31.55%). Brooklyn and Queens approached 40% of normal ridership, and the Bronx had the largest resurgence of activity at 45%.
“Even as stations in Manhattan that were once the busiest in the city remain eerily quiet — with as few as one-fifth of typical passenger levels — ridership at some stops in the other boroughs has surpassed 50 percent of pre-pandemic levels.”
When we do the same calculation as above for individual stations, we can see a broad range of percentages. Here are the top 15 and bottom 15, but most are in the middle somewhere:
A quick histogram of the percentages shows the distribution more clearly.
Borough Breakdown
Creating the same histogram for each of the four boroughs served by the subway shows clearly distinct patterns. In the Bronx we see a much smaller range pushed toward the higher end of the scale around the 40% mark. In Manhattan the pattern is more erratic, but skews to the lower percentages. We can also see that all three of the outliers are stations in Queens.
“In the months since, the system’s revival has been similarly skewed: Ridership has returned to about 40 percent of normal in Brooklyn and 45 percent in the Bronx. In Manhattan, ridership is still just 25 percent of what it was before the outbreak.”
Here’s the same data in the table above, as a chart, showing the four boroughs served by the subway along with the citywide percentage.
Finally, a map allows us to see individual stations and observe the overall patterns. The stations in Manhattan with low ridership are mostly clustered in midtown and below, and we can see the small selection of stations throughout the city where ridership has surpassed 50% of usual.
Thanks for reading!
The code used in this analysis is available on github.
The dataset, NYC Turnstile Daily Counts 2020 is available on qri.cloud.
