Tuesday, November 27, 2012

1945 Network Model vs Today: Or How I learned Why Dallas Moved Northward























These were asked for at a similar scale and here they are, the space syntax network integration models for Dallas 1945 (above) and Dallas of today (below).  Note: the Dallas of today isn't finished, nor does it include the entire metroplex, which may or may not effect the model. If you're unfamiliar with these network integration models, they are in effect heat maps of street networks.  The most integrated show up as red areas, which have been statistically shown (in more urban cities) to correlate with increased density, real estate, value, foot traffic, as well as reduced crime.

What is clearly apparent is how the red areas shifted northward with the introduction of the freeways and the effect the freeways then had upon growth towards the "favored quarter," in Chris Leinberger's speak, thus creating a self-fulfilling vicious circle of northern expansion and decentralization.  And that's fine, I suppose, but what's more important is the LOSS of value in and around the core.

As I've said before, highways take land at the edge from a hypothetical value of 1 and improve them to 2.  There is a profit model built-in there. Meanwhile, the intra-city highways take downtown land from a value of 10 to a similar value of 2 (as we saw in our highway 345 study which shows $77,500 in improvements (ie buildings) per acre.  The effort to reduce congestion creates anti-city, by its very purpose.  And we end up with anti-city at the edge (sprawl) and anti-city in the core (except for a few small pockets).  See the walkscore heatmap:



I've also said before the horrible irony is that downtown developers were building the biggest buildings, the downtown high-rises at the same time that state and federal monies were pumped into highways thereby sapping the demand for all that new supply.