The State of Transit Routing

My brother called me a week ago and during the course of our conversation mentioned that he made the trek to the Miami Auto Show. He was complaining that he really wanted to take Tri-Rail (the commuter rail that runs along Florida’s South East coast) but it was just too hard to figure out the rest of the trip once he got off the train. “One web site for train schedules, another for buses, and another for a city map to tie it all together. It was just too much trouble to figure out, so I drove. I just want to go online and get directions just like I do for driving, but that tells me which train, which bus, etc.”

Coincidentally, later in the day I downloaded the iPhone 2.2 upgrade with the new walking and public transit directions. So far, at least where I live, it’s useless. The little bus icon just sits there grayed out, taunting me. I guess because SEPTA (our local transit authority for bus and regional rail) isn’t giving data to Google?

My brother hadn’t heard of Google Transit, but It turns out to have some coverage in Miami. Their coverage at this point seems to be transit authority centric and doesn’t seem to have great support for mixed mode or stuff that crosses transit system boundaries. I am curious though, is it being used? Let me know in the comments if you are using it to good effect.

Anyway, my brother’s call on the same day as the iPhone update piqued my interest in the current state of the art for mixed mode transit routing. After some mostly fruitless web searches for I reached out to Andrew Turner. I knew he’d know what was going on in. This is what he had to say:

Routing is definitely one of the emergent areas of technology in the next generation applications. So far, we’ve done a great job getting digital maps on the web, mobile locative devices, and comfortable users.

One problem for awhile has been the lack of data. You can have a great algorithm or concept, but without data it’s useless. Gathering this data has been prohibitively expensive – companies like NAVTEQ drive many of the roads they map for verification and additional data. Therefore if you wanted to buy road data from one of the vendors you had to have a large sum of money in the bank and know how you were going to monetize it. This stifled experimentation and creating niche applications.

Now that the data is becoming widely, and often freely, available innovation is happening at an increased pace.

For one example, consider the typical road navigation. The global OpenStreetMap project has always had topology (road connectivity), but the community now adding attribute data to ways such as number of lanes, stop lights, turn restrictions, speeds, and directionality. Anyone can download this data to use with a variety of tools such as pgRouting. As a result people are rethinking standard routing mechanisms that assume travel from A to B via the fastest, or shortest, route. What if a user wants to take the “greenest” route as determined by lowest total gas mileage, or the most scenic route based on community feedback.

An area that has strongly utilized this idea has been disaster response. Agencies and organizations deploy to areas with little on the ground data, or data that is now obsolete due to the disaster they’re responding. Destroyed bridges, flooded roads, new and temporary infrastructure are just some of the aspects that are lost with typical navigation systems. However, given the capability of responders to correct the data and instantly get new routes is vital. And these routes may need to be based on attributes different from typical engines – it’s not about the fastest, but which roads will handle a 5-ton water truck?

This scheme was deployed in the recent hurricane response in Haiti in conjunction with the UNJLC, CartOng, OpenStreetMap and OpenRouteService.

Beyond just simple, automotive routing, we can now incorporate multi-modal transit. With 50% of the world’s population now living in urban areas, the assumption that everyone is in a car is not valid. Instead people will be utilizing a mixture of cars, buses, subways, walking, and bicycling. This data is also being added to OpenStreetMap as well as other projects such as Bikely or EveryTrail. GraphServer is one routing engine that will incorporate these various modes and provide routes.

And we’re interfacing with all these engines using a variety of devices: laptop, PND (Personal Navigation Device), GPS units, mobile phones, and waymarking signs. PointAbout recently won an award in the Apps For Democracy for their DC Location Aware Realtime Alerts mobile application that displays the route to the nearest arriving metro.

What’s also interesting is the potential of these routing tools beyond actual specific individual routes. Taken in amalgamation the routing distances form a new topography of the space. Given a point in the city, how far can I travel in 20 minutes? in 40 minutes? for less than $1.75? This type of map is known as an isochrone. Tom Carden and MySociety developed London Travel Time Maps that allow users to highlight the spots in London given a range of house prices and travel times.

Despite these apparent benefits, there is a large hurdle. Like road data, there has been a lack of openly available transit data to power applications and services. Providers like NAVTEQ and open projects like OpenStreetMap are possible because the public roads are observable and measurable by any one. By contrast, the many, varied local transit agencies own and protect their routing data and are reluctant to share. Google Transit has made great strides in working with transit authorities to expose their information in the Google Transit Feed Specification – at least to Google. This does not mean the data has to be publicly shared, and in many cases this is exactly what has occured.

However, not even the allure of widely admired Google Transit can induce transit authorities to share their prized data. The Director of Customer Service of the Washington Metro Area Transit Authority (WMATA) plainly states that working with Google is “not in our best interest from a business perspective.”

Hopefully, this situation will change, first through forceful FOIA requests, but later through cooperation. One step in this direction have been TransitCamps. And Portland’s TriMet is a shining example with a Developer Resources page detailing data feeds and API’s.

These experimentations are just the beginning of what is being pushed in the space. Routing is one of those features that users may not realize they need until they have it and then they’ll find it indispensable. The ability for a person to customize their valuation of distance to assist in making complex decisions and searching is very powerful.

For more projects and tools, check out the OpenStreetMap routing page, Ideas in transit and the OGC’s OpenLS standards.

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