Visualizing a Public Good

Posted on 03/25/2011 by


Have you ever been waiting for a bus for half an hour, only for two half-filled buses of the same route to roll up to your stop? Known as bus bunching, this can be an incredibly annoying experience, especially if you see many buses pass by in the opposite direction while you’re waiting. Luckily for you (well, if you live in Chicago), public transport authorities have been working to fix this using all kinds of real-time bus data and nifty visualizations. Not only might it help you get to work on time, but it also shows how small perturbations in a complex system can dramatically effect performance.

In a paper released by the Chicago Transit Authority (CTA) and the Civic Consulting Alliance (CCA), bus position data was analyzed to see what causes the large gaps in service that customers find so annoying. Some of the factors identified include equipment failures, late personnel and buses filled beyond capacity (leading to long loading times). As seen below, even one malfunction can result in large service gaps that persist for many stops:

What can be done? On one hand, the CTA should be lauded for providing real-time location data to customers via the CTA Bustracker, which gives transit users the information they need to be able to decide when to leave to catch a bus. This information is less useful, though, if you need to transfer between multiple buses or trains, or if you are in a rush. So has all of this information made bus service more reliable? Well, you be the judge.

Perhaps Chicago’s government isn’t so notoriously corrupt after all?