If you had the opportunity to design a new subway line for your city, where would you put it?  Where should the stations be?  Working with the World Bank, we recently released an open-source tool, called Open Transit Indicators, that will help transit planners answer these types of questions.  Open Transit Indicators enables users to assess the quality of existing transit systems, design scenarios for expanding or changing their cities’ transit systems, and compare measurements of service quality between different cities.

The Open Transit Indicators project was developed by the World Bank, in partnership with the Chinese Academy of Transport Science and the Haiphong Department of Transportation (Vietnam).  The application uses information about a city’s transit system, along with additional data about demographics, to calculate baseline indicators of transit service quality, such as average distance between transit stops and average service frequency.  The service quality indicators can then be used to compare one city’s transit system to those of other cities, identify possibilities for service improvement, and evaluate the effect of hypothetical service changes.

For example, we can compare Zhengzhou, China (about 4 million people) to Philadelphia and Chicago:

You can see that Zhengzhou runs its buses at a much higher frequency than Chicago and Philadelphia, perhaps to compensate for its lack of a subway system.  Chicago and Philadelphia appear to have better coverage of their urban areas with transit stops, but this may come at the cost of having less frequent service.

To identify areas where service might be improved, data is also made available on a route-by-route basis.  Below is a map of the average distance between stops in Zhengzhou for each bus route.

Red routes have their stops closer together, while blue routes have them farther apart.  You can see that there’s a rough division between routes that service the urban core, which have closely spaced stops, and those routes that extend out to the periphery of the city, which have their stops farther apart.

There’s a lot that goes into choosing where to put a transit line, of course, but one option in this case might be to place a new subway line along the paths of some of the existing long-haul bus lines.  Doing this could allow the transit agency to shift bus capacity to cover a greater percentage of the city’s area by placing stops closer together on other routes.  Here is a possible scenario for building such a subway line in Zhengzhou:

To continue with this example, a transit planner might design several different subway routes; Open Transit Indicators will calculate updated metrics for each scenario so that the scenarios can be compared with each other and with the original system.

If you’d like to see how your own city’s transit system stacks up, or want to know what it would be like to have a subway stop right outside your front door, you can.  Open Transit Indicators imports information about transit systems using the GTFS format (General Transit Feed Specification); many cities already make information about their transit systems available in GTFS format, so they can be analyzed and compared using the app.  As its name implies, Open Transit Indicators is open source and freely available, so anyone can use it to design the perfect transit system for their city.  Just download the source code from GitHub, and get started!