The Unofficial Chicago Transit Authority API

Kevin Farnham, December 8th, 2008

Chicago commuters just got a new resource that may lead to more helpful mashups: the Chicago Transit Authority Bus Tracker API. As recently announced, the API provides capability for developers to get bus routes and schedules, bus stop and arrival predictions, and more. Note that the API is not affiliated with the Chicago Transit Authority (CTA); rather, it was developed and is maintained by Harper Reed, who says the CTA has been “amazingly cool with all of this.” In announcing the API, Harper wrote:

The genesis for this API is some work I did awhile ago reverse engineering the CTA Bus Tracker mashup. I was able to expose the endpoints that powered their google maps mashup. In its original state – you can get some pretty awesome functionality and data. I am attempting to clean it up and make it more robust.

We have added a Chicago Transit Authority API profile and a CTA Bus Tracker mashup profile to our directory.

Chicago Transit Authority Live Bus Map

Reverse engineering an API requires a lot of creative investigation into the source code that is publicly available in mashups that apply the undocumented API. For example, we recently reported on Index Content’s discovery of “Reddit’s Secret API”.

The unofficial CTA API is REST-based, includes docs, and has API mailing list to keep developers up to date on API issues and enhancements.

The Commuting In Chicago site applies the CTA Bus Tracker API to allow users to set schedules and preferred bus routes. As you revisit the site, the application recommends bus routes and shows current bus locations that correspond to your routes.

Last week we reported on the innovations the BART API is providing to developers of San Francisco transit mashups. They may be new, but we already have 6 transit APIs in our directory. The mashups they enable should provide a new and exciting service for city transit users.

Tags: Gov
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4 Responses to “The Unofficial Chicago Transit Authority API”

December 10th, 2008
at 10:01 am
Comment by: links for 2008-12-10 « Brent Sordyl’s Blog

[...] The Unofficial Chicago Transit Authority API Chicago commuters just got a new resource that may lead to more helpful mashups: the Chicago Transit Authority Bus Tracker API. As recently announced, the API provides capability for developers to get bus routes and schedules, bus stop and arrival predictions, and more. Note that the API is not affiliated with the Chicago Transit Authority (CTA) (tags: api chicago transit) [...]

January 14th, 2009
at 3:17 pm
Comment by: commuting.in » Blog Archive » commuting.in mentioned on ProgrammableWeb

[...] Our alpha version of Commuting.in was mentioned on ProgrammableWeb [...]

January 16th, 2009
at 11:03 am
Comment by: Guest Post: How the CTA bus tracking was hacked. | Ryan A Graves.com

[...] The Unofficial Chicago Transit Authority API [...]

January 27th, 2009
at 3:26 am
Comment by: Hacking Chicago’s Unofficial Transit API

[...] in our post on the Unofficial Chicago Transit Authority API we reported on this unofficial transit API for the CTA. The API enables developers to build [...]

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