An urban transportation system is a messy, hard-to-track thing.
Despite planning surveys and increasing data aggregation, it's hard for the people who run city transit to know precisely what is happening within their systems, quantitatively, and in formats that their employees can understand.
It was that realization that led former Googler Shiva Shivakumar and Balaji Prabhakar, a Stanford computer science professor, to found UrbanEngines, a company that uses math to infer the real-time state of a transit system merely from the people entering and exiting the system.
They suck in where and when people board transit, and they spit out what they're calling a digital replica of the city's transportation network.
If you grew up playing SimCity like I did, and you remember all the buses and trains moving to and fro: that's actually what this system outputs. And it does so with existing data that transportation agencies are already collecting.
The company launched this week with the announcement of first three "partner cities:" Sao Paolo, Singapore, and Washington, D.C.
I met up with the co-founders in San Francisco last week to learn how the system worked. (It was actually my second encounter with Prabhakar, who has been interested in using computer science to understand societal not social networks.)