New York City Citi Bike Trip Pattern in March 2020
Where did trips start, end, and how were they congregate?
Hanzhang Yang is an urban informatics newbie and urban planner.
For this research, I will be looking at NYC Citi Bike data.
To choosing one month of NYC Citi Bike trip data, the March 2020 data come to my mind. On March 20, 2020, Governor Cuomo of New York State issued a state-wide PAUSE order that would go into effect on March 22, 2020, at 8 PM. With the non-essential businesses being shut down, how New Yorkers use public transportation dramatically changed. How the Citi Bike users utilize this new urban transportation infrastructure, which is seven years old now?
Metadata for Citi Bike trip data provided on Citibike’s website:
- Trip Duration (seconds)
- Start Time and Date
- Stop Time and Date
- Start Station Name
- End Station Name
- Station ID
- Station Lat/Long
- Bike ID
- User Type (Customer = 24-hour pass or 3-day pass user; Subscriber = Annual Member)
- Gender (Zero=unknown; 1=male; 2=female)
- Year of Birth
Basic Descriptive Analysis of the Citi Bike Trip Data from March 2020 in New York City
Usage by Time
From the March 2020 Citi Bike trip data, we learned that 1,068,457 trips happened during that month, which means 34,466 trips per day. A bar chart for the daily Citi Bike Ridership in March 2020 shows that on March 8, 68,768 trips being ride, and on March 23, only 3,999 trips were ridden by New Yorkers, reflected the city-wide quarantine impact brought by the PAUSE order.
Usage by Age and Gender
Interestingly, the Citi Bike users’ birth year ranged from 1885 to 2004, which is not “true” because the oldest person living currently is Kane Tanaka, who was born in 1903.
We can find a spike in the chart, which means more than 80,000 trips in March 2020 were riding by users “born” in 1963. It is abnormal. So I grouped the trips by birth year and gender.
72,252 trips were finished by users identified as unknown gender and born in 1969. After some research on the Internet, I learned that the default birth year in a Citi Bike user’s profile is 1969. Many users didn’t change their default birth year and gender; maybe that’s why we can found an abnormal number of Gen X using the Citi Bike!
Also, we can found that in March 2020, 3x more ridership was used by the male riders to female riders.
Where is the Citi Bike Station?
In this map, each red dot represented a Citi Bike station, and blue lines are the New York Subway routes. While all the bike docks were concentrated in Manhattan and its adjacent parts in Queens and Brooklyn, some docks could be found outside the New York City. It is because Citi Bike also operated across the Hudson River in Jersey City, NJ.
Most used Citi Bike Station
These five stations were used the most in March 2020, each with more than 10,000 riders started or ended within one month period.
One Citi Bike, number 37042, being rides the most this month. It contributes 384 trips to the total 1,068,457 in March 2020. Let’s see where did it go in March?
OD Analysis with Network X for Citi Bike Trip Data in March 2020
I created spatially located nodes from Citi Bike trip data by extracting station names and both “start” and “end” station coordinates from the data frame and put in trips as edges to this Network.
Incoming and Outgoing Degree
The top 10 stations with the most incoming degree and the top 10 stations with the most outgoing degree were:
The Centrality of the Stations
After calculating 1) degree centrality, 2) eigenvector centrality, 3) betweenness centrality, and 4) closeness centrality for the network, all centralities results show that one station “S 5 Pl & S 5 St” is on top of each centrality score. Why the station “S 5 Pl & S 5 St” is so important in the network?
Because this station is located at the Brooklyn side entrance of Williamsburg Bridge, a cross-borough street between Brooklyn and Manhattan, every day, numerous tourists and locals will walk or bike through the bridge, the Citi Bike station right at the entrance of the bridge is a perfect place for a cyclist to rent a Citi Bike to experience New York.
Other stations with high centralities are located in the dense urban area, which already becomes tourists or New Yorkers’ thoroughfare or congregation place long before Citi Bike.
Visualize the Citi Bike Trips Network
From this map, we noticed that the “central” of Citi Bike trips could easily be identified in the area across mid-downtown Manhattan. Also, many high-degree nodes were located along Broadway, the main arterial of Manhattan, or we can say, New York.
Understanding the Station: S 5 Pl & S 5 St
(updated Dec 7, 2020)
To understand why the Citi Bike station S 5 Pl & S 5 St is the star of March 2020, I filtered only the trips related to this station from the monthly dataset used in the above research.
The node size and edge weight were being logarithmized by using math.log1p function to avoid oversized graphs. Calculating the log for (x+1) avoids error from unused stations’ original node size and edge weight (both = 0).
Many trips start/end in this station come from Manhattan, which means a lot of cyclists using Citi Bike to travel across the Williamsburg Bridge.
This story is uploaded for PLA6619 Intro to Urban Data and Informatics, taught by Dr. Boyeong Hong.
