Radial Routes vs. a Ring Route

Hans Klein 27 February 2023

Transit systems have a "system architecture". That is what is shown on a route map.  The system architectures of most transit systems-- and most transportation systems in general --  emphasize radial routes (or "spoke" routes) that radiate out from areas of concentrated economic activity, because radial routes connect (concentrated) areas of economic activity and with (dispersed) areas of residential living. They connect the "core" to the "periphery." If  you examine any city’s transit maps, you will  find lots of radial routes.  (E.g. see: https://fiftythree.studio )

When we lament car culture and traffic jams, we are referring to people traveling from the periphery to the core and back again.  In Atlanta, the periphery might be Inman Park, Westview, or Vinings, or it might be Dunwoody or Stone Mountain.  In Atlanta, there are multiple cores, but they are still concentrated. The main ones are Midtown, Downtown, and Buckhead.

If Atlanta already had radial transit routes to its cores economic activity,  we might move on the next thing, a complementary ring route (e.g. on the Beltline.)  But we are not there yet;  we still lack sufficient radial routes. For that reason it is (at best) premature to deploy transit on the Beltline ring route. A ring route without numerous radial connections doesn't match the travel patterns of most residents.  MARTA’s and ABI's Beltline streetcar plan is unusual (unique?) in prioritizing a ring route over radial routes.

By spending public funds on a ring route for which there is little or no demand, we misallocate $230,000,000 (nearly a quarter of a billion dollars!) of transit capital – enough to build a lot of transit in Atlanta.

The good news is that the MORE MARTA plan, which is funding transit expansion,  does include numerous radial routes. It is those radial routes that are needed.  MARTA should build out those radial routes first.  MARTA should change its priorities to favor radial routes.

Note that the proposed streetcar, once it enters the Beltline, crosses no fewer than 4 radial arterial roads:  Irwin, Ralph McGill, North, and Ponce.  Each of those radials could host transit.  The small minority of commuters who want to go across those radials could use LIT on the Beltline. They might even walk, since the distances between radials is so small.  The tiny minority of travelers who cannot use LIT would be good candidates for MARTA’s on-demand transit service.

When we factor in time, we experience even greater urgency to build radial routes.  With every passing year, it will be harder to reserve transit rights of way on radial roads.  In contrast, there is no urgency to deploy transit on the Beltline' circular right of way, because the right of way is reliably established.Today we can simply defer Beltline deployments to a future date.

The bottom line:  MARTA should prioritize transit deployment on radial routes.  ABI should prioritize LIT deployment on the Beltline (by adding a cycle track.) Should future demand warrant it (a big question,) transit on the Beltline could be deployed. But such a circle route always comes after deployment of radial routes.

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