The I-16 flyover removal and traffic flow

By bill dawers On October 10, 2011 · Leave a Comment · In Living Savannah, Urban Form

In my City Talk column on Sunday, much of which was devoted to the new coffeeshop Foxy Loxy, I closed with a brief overview of how the removal of the I-16 flyover will actually improve traffic flow in the southwest quadrant of the Historic District. I know that conclusion is counter-intuitive — we expect removing road capacity to hurt traffic.

But the flyover is pretty much a straitjacket; it forces drivers to go places they may not want to go, it shuts down other logical options and creates problems on its edges, it limits the options of drivers who have no intention of getting on the highway, and it provides a quick route into the city at the expense of even a halfway acceptable route out.

This isn’t just me making this up, by the way. Urban planners like Christian Sottile have long advocated the removal of the flyover, and the technocracy of GDOT has endorsed the removal as not only acceptable, but as an improvement over the current configuration.

The single weakest argument against the removal is also the one that I hear the most, at least among those objections dealing with traffic. As I noted in the column, I’m constantly hearing people say that MLK can’t handle the additional incoming traffic, but every single car leaving the city via I-16 has to travel on or across MLK already.

Let’s look at the various projected traffic maps for 2035 from the relevant document on the page devoted to the project at the Metropolitan Planning Commission’s site:

First, here’s the traffic level of service map for 2035 for the current patterns:

Then there are three different concepts (click on each for a larger version):

Concept 1

Concept 2

Concept 3

Obviously, the darkest green areas represent the best levels of service with the red being failing levels. Note that in the current configuration, we will have failing levels on the blocks of MLK leading onto I-16 westbound, as well as significant red areas on Liberty Street and Oglethorpe Avenue. In all three of the concepts, we see some of the dark green replaced with a lighter green, which indicates perfectly fine but not quite A-level of service, but we also see significant improvements on MLK for traffic that wants to get on I-16 (right now, that traffic gets on the highway pretty much one car at a time), and we see significant improvements to traffic flow on both Liberty and Oglethorpe.

Concept 1 is the simplest and least expensive to implement; it’s also the concept that seems to have the least impact on traffic flow. It’s also the least ambitious concept, however, and will pay fewer economic dividends both over the short run and over the long run.

But I’ll be dealing with some of the economic issues in a future column. If you want to see even larger versions of these maps with all the markings legible, go here.