Hubway Data
Visualization Challenge

By Zia Sobhani

Hubway Station Connectivity Matrix

This graphic provides a breakdown of all station to station Hubway traffic, by month and by hour for the first 15 months of Hubway operation.

At the macro level, looking from top to bottom, you can see the growth of Hubway traffic since the system started in July 2011 (top row), to August 2012, on the bottom. Seasonal decline is visible near the winter months when Hubway does not operate (central black band). Notice the top-bottom symmetry around the winter, with fewer evening riders in November and March. Variation throughout the day is visible from left to right. Quiet activity in the night swells for commuter/work day traffic. If you look very carefully you may see commuter bands at 8am and a more general swell between 4-6pm, which is explained by higher causal use of the system in the afternoons. At the pixel level you can see the inter-connectivity of the 95 Hubway stations represented in the data-set. Each hour/month combination creates a 95x95 pixel matrix. Each pixel in this grid is colored to represent the number of trips that originate at the station specified by the row index which ended at the station specified by the column the pixel is in. The stations were organized roughly by neighborhood and the list and pixel indexes are provided at the right.

A first thing to notice in these small matrices are the diagonal bands running upper left to lower right. These represent the 7% of the total trips that started and ended at the same Hubway station. Clusters around diagonal indicate traffic within neighborhoods. Boston, with the commuting hot spots of North Station and South Station, is unexpectedly the brightest region of the matrix. Interestingly, in the evenings the city traffic doesn't really stand out.

Looking at the top to bottom trend you can see the addition of stations throughout Hubway's operation, most notably several new stations in July and August 2012, which fill in the empty spaces from before those stations were installed. It is interesting how interconnected the stations are, with even the furthest station distances having been traveled by some intrepid rider. It is also interesting to note that approximately half of the colored pixels represent only one trip made between those stations during that month. Most of the traffic are the expected commuters and tourists.

Full resolution image can be viewed at