Cabi Flow Analyzer

Every quarter, a new set of data gets added to Capital Bikeshare’s repository of trip-history data. And as the Washington D.C. region’s bikesharing system grows more popular, the data sets grow in size (from 15 megabytes and 117,972 trips in the 4th quarter of 2010 to 68 megabytes and 637,531 trips in the 3rd quarter of 2012).

How best to sift through the mounds of data and find meaning?

Cabi FlowThe “CaBi Trip Visualizer” is a new tool I developed that lets you analyze 2012 3rd-quarter Capital Bikeshare data, using arrows along a map to illustrate where riders are going to and coming from. The thickness and opacity of the arrow reflects the relative ridership levels. Hovering over an arrow presents a display of the numeric values for that segment.

You can try out the tool at http://mvjantzen.com/cabi/trips3q2012.html.

For each station you select, the most-common route is drawn with an arrow 10-pixels thick. Segments to other stations that are less than 10 percent of that value are not included in the map (since the lines would be less than 1 pixel). This also prevents outlier trips from forcing the boundaries of the map’s view to be too large. (You can still zoom and pan within the map.) Be sure to play with the multiple-station options, at the bottom of the drop-down menu, such as looking at travel patterns for stations on the Mall.

Notice any insightful patterns? Ideas for how to improve the tool? Let us know what you discover in the comments below. (The JavaScript behind the scenes was modified from a bubble map made for the 2011 4th-quarter data, which you can see at Looking at CaBi Stats with a Bubble Map.)

More Number-Crunching

  • Hungry for more statistics from the new data? The average distance between end-points was 1,858 meters (1.2 miles). This excludes trips that began and ended at the same station (as happens in almost 5 percent of all trips). And of course the trips were certainly longer than the distance calculated as the crow flies.
  • 80 percent of the third-quarter’s trips were made by registered users (those who sign up for a month or a year). Casual users (who made 20 percent of the trips) sign up for 1 or 3 days.
  • The busiest station by far is the one on Massachusetts Avenue, just west of Dupont Circle (measuring check-outs and ignoring check-ins). In fact, 2.8 percent* of all bikeshare trips begin at the Dupont Circle station. The second-busiest station is the one at 15th & P streets NW (1.9 percent of all trips). And the third-busiest station is at 14th & V streets NW, outside of the Reeves Center (1.6 percent of all trips).
  • The casual users prefer the stations closer to the Mall. Their favorite station for checking out a bike is at Jefferson Drive & 14th Street SW. That station is used to begin 5.8 percent of all casual trips. It’s followed by the one at 19th Street & Constitution Avenue NW, which gets 4.1 percent of all casual trips, and then in third place we’re back to Massachusetts Avenue & Dupont Circle NW, where 2.9 percent of all casual trips begin.

*Keep in mind that with 190 stations, each station represents 0.53 percent of the total.

This article is by Michael Schade from mobilitylab.org.