TagMapzen

This map shows how transit access from Uptown would diminish if the Red Line wasn’t there

The dark pink shows areas you can get to within 45 minutes by transit, and the light pink shows you how far you can get within 60 minutes of transit. The transit shed without the Red Line is much smaller!

I virtually dismantled the Red Line to show how important it is to get around the North Side via transit.

Mapzen, a fantastic company that makes free and open source mapping tools, and for whom I’m an independent contractor, updated its Mobility Explorer map to show where you can go from any point in a city by transit if a piece of existing transit infrastructure didn’t exist.

So, I handily took out the Red Line – the Chicago workhorse, carrying 145,000 people each weekday north of State/Lake station. The map shows the analysis, called an isochrone, as if you were departing from the Wilson station in Uptown.

Try it yourself.

You can download the map as a GeoJSON, open it in QGIS, and measure the area in square miles that each scenario covers.

Bicyclists in Chicago can travel pretty far in 15 minutes

Mapzen* released Mobility Explorer last week. It is the graphical user interface (GUI) to the Transitland datastore of a lot of the world’s transit schedules and maps.

It also has isochrones, which are more commonly known as “mode sheds”, or the area that you can reach by a specific mode in a specific amount of time.

I wanted to test it quickly to see what these mode sheds say about where I live, a block north of Humboldt Park. From my house, on a bicycle, I can reach the edges of an area that’s 25 square miles in 15 minutes.

Isochrones map of transportation distance from my house

The distance you can travel from my house at the north end of Humboldt Park in 15 minutes by three modes, assuming you leave at 2:21 PM today (in increasing distance/area): Transit (dark purple) Bicycling (burgundy) Driving (pink)

You can request these isochrones through this API call for any location and they’ll be returned as GeoJSON.

I’m still learning how isochrones work, and how they can be adjusted (to account for different rider seeds and route costs or penalties). One difference between bicycling and driving is that the driving area is increased by expressways while the bicycling area has a more uniform shape.

The bike shed is 25.7 square miles, and the driving shed is 52.0 square miles.

*I do contract work for Mapzen and maintain parts of the Transitland Feed Registry.

The U.S. DOT should collaborate with existing “National Transit Maps” makers

The U.S. DOT demonstrated one idea for how a National Transit Map might look and work at a conference in February.

The Washington Post reported this month that the United States Department of Transportation is going to develop a “National Transit Map” because, frankly, one doesn’t exist. The U.S. DOT said such a map could reveal “transit deserts” (the screen capture above shows one example from Salt Lake City, discussed below).

Secretary Anthony Foxx wrote in an open letter to say that the department and the nation’s transit agencies “have yet to recognize the full potential” of a data standard called the General Transit Feed Specification that Google promoted in order to integrate transit routing on its maps. Foxx described two problems that arose out of not using “GTFS”.

  1. Transit vehicles have significantly greater capacity than passenger cars, but are often considered just vehicles because we are unable to show where and when the transit vehicles are scheduled to operate. The realistic treatment of transit for planning, performance measures, and resiliency requires real data on transit system operations.
  2. One of the most important social values of transit is that it makes transportation available to people who do not have access to private automobiles, and provides transportation options for those who do. Yet, we cannot describe this value at a national level and in many regions because we do not have a national map of fixed transit routes.

“The solution is straightforward”, Foxx continued, “[is] a national repository of voluntarily provided, public domain GTFS feed data that is compiled into a common format with data from fixed route systems.”

The letter went on to explain exactly how the DOT would compile the GTFS files, and said the first “collection day” will be March 31, this week. As of this writing, the website to which transit agencies must submit their GTFS files is unavailable.

What Foxx is asking for has already been done to some degree. Two national transit maps and one data warehouse already exist and the DOT should engage those producers, and others who would use the map, to determine the best way to build a useful but inexpensive map and database. Each of the two existing maps and databases was created by volunteers and are already-funded projects so it would make sense to maximize the use of existing projects and data.

“Transitland” is a project to host transit maps and timetables for transit systems around the world. It was created by Mapzen, a company funded by Samsung to build open source mapping and geodata tools. Transitland is also built upon GTFS data from agencies all over the world. Its data APIs and public map can help answer the question: How many transit operators serve Bay Area residents, and what areas does each service?

For the United States, Transitland hosts and queries data from transit agencies in 31 states and the District of Columbia. In Washington, D.C., Transitland is aware of four transit agencies. It’s a great tool in that respect: Not all of the four transit agencies are headquartered in D.C. or primarily serve that city. The app is capable of understanding spatial overlaps between municipal and regional geographies and transit agencies.

Transitland has a “GUI” to show you how much transit data it has around the world.

“Transit Explorer” is an interactive map of all rail transit and bus rapid transit lines in the United States, Mexico, and Canada. Yonah Freemark, author of The Transport Politic, created the map using data culled from OpenStreetMap, the National Transit Atlas Database (administered by the DOT and which shows fixed-guideway transit), and his own research. I wrote the custom JavaScript code for the Leaflet-powered map.

No other agency or project has collected this much data about fixed-guideway transit lines in any of the three countries, since the map includes detailed information about line lengths, ridership, and other characteristics that are not included in GTFS data. Transit Explorer, though, does not include local bus service or service frequencies, which the DOT’s map may if it incorporates the full breadth of GTFS data.

Transit Explorer also goes a step further by providing data about under construction and proposed fixed-guideway transit lines, which is information that is very relevant to understanding future neighborhood accessibility to transit, but which is not available through GTFS sources.

Finally, “GTFS Data Exchange” is a website that has been storing snapshots of GTFS feeds from agencies around the world for almost a decade, or about as long as GTFS has been used in Google Maps. The snapshots allow for service comparisons of a single agency across time. For example, there are over 100 versions of the GTFS data for the Chicago Transit Authority, stretching back to November 2009; new versions are added – by “cta-archiver” – twice a month.

Josh Cohen, writing in Next City, highlighted the significance of Google’s invention of GTFS, saying, “Prior to the adoption of GTFS, creating such a map would’ve been unwieldy and likely produced an out-of-date product by the time it was completed.” The DOT’s own National Transit Atlas Database includes only fixed-guideway (a.k.a. trains) routes, and hasn’t been updated since 2004.

Not all GTFS feeds are created equal, though. Some transit agencies don’t include all of the data, some of which is optional for Google Map’s purpose, that would make the National Transit Map useful for the spatial analysis the DOT intends. Many agencies don’t include the “route shapes”, or the geographic lines between train stations and bus stops. Researchers are able to see where the vehicles stop, but not which streets or routes they take. Foxx’s letter doesn’t acknowledge this. It does, however, mention that transit agencies can use some federal funds to create the GTFS data.

David Levinson, professor at the University of Minnesota, believes the map will bias coverage (geographic reach of transit service) over frequency (how many buses are run each day that someone could ride).

The U.S. DOT’s chief data officer, Dan Morgan, whom I met at Transportation Camp 2015 in Washington, D.C., presented at the FedGIS Conference this year one idea to demonstrate coverage and frequency in Salt Lake City, using the GTFS data from the Utah Transit Authority.

Levinson also tweeted that it will be difficult for a national map to show service because of the struggles individual transit providers have symbolizing their own service patterns.

Foxx’s letter doesn’t describe how planners will be able to download the data in the collection, but whichever app they build or modify will cost money. Before going much further, and before spending any significant funds, Foxx should consult potential users and researchers to avoid duplicating existing projects that may ultimately be superior resources.

Foxx can also take advantage of “18F” a new agency within the General Services Administration to overcome government’s reputation for creating costly and difficult to use apps. The GSA procures all kinds of things the federal government needs, and 18F may be able to help the DOT create the National Transit Map (and database) in a modern, tech and user-friendly way – or write a good RFP for someone else to make it.

Look for the National Transit Map this summer.

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