Alligator Urbanism

I'm back from my favorite town...Savannah, and new thoughts on odonomy abound (more later). I just spent a week surveying great developments in South Carolina and Georgia.
















The development work I was most struck with were the interesting developments on the Marietta Street Corridor in Atlanta and DPZ-planned Habersham, near Beaufort, SC (all the photos here are of Habersham).

The biggest surprise of the trip was my first visit to Hilton Head Island, which I may blog more about later. Hilton Head showed me that a sustainable type of sprawl actually exists. Its really remarkable job integrating infrastructure for bike/ped transport was some of the most stellar I've ever seen. Of course, Hilton Head was built for bike use from its inception, and its relentlessly controlled planning represents a resort-style urbanism (or sustainable sprawlism?), the kind that is way out of the adoptable range and integrative capacity of most suburban communities. But the respect to the landscape was superb. Hilton Head's nearly unbroken sea pine canopy and high standards for vegetated screening are a work of amazement. You really do get the impression that alligators coexist happily with humans in that sprawl. I'm surprised as a planner that I haven't heard more about Hilton Head, especially as we are now increasingly confronted with the problem of sustainably "retrofitting" our suburbs.

Both Hilton Head and Habersham made me appreciate the potential of landscape design to make sprawl more sustainable...and a rich experience - the kind that appeals strongly to most Americans. Call it golf-cart urbanism if you like, but I really like it when golf-course tested landscape architects get involved in urban design. The results are very interesting, and I was quite surprised at the level of thought we can glean from these experts to carry over into our TOD's and urban developments.

















So far, Habersham is the best TND sprawl I've seen (but...my...what beautiful and interesting sprawl!). While Habersham for sure appeals to the second home 55 and over crowd that populates these places around Hilton Head, evidence abounds that a fair amount of families with children live in the neighborhood.

If you are an urban designer, landscape architect or planner, a good vacation to consider is a trip to Savannah/Hilton Head. You are guaranteed at least three treats: Savannah's Historic District (with its unparalleled grid of insights - yes more odonomic contemplation is in order!), Hilton Head Island's tremendously cohesive and well-integrated bike paths (with a trail system featuring boardwalks through the swampy areas, BMP's and parks), and Habersham.

Habersham, in a way, represents a more urbanistic approach to do Hilton Head, and it employs road and landscape design at a level of subtlety that left me there for hours carefully observing the details. To me it represents the best imaginative work of DPZ I've seen so far. You can tell they really went out of their way to prove that design for 18 mph can be interesting - never "one size" and "one solution" and always respecting and purposefully integrating the existing trees and site conditions.

If you do go... Do NOT forget...Be sure to bring a bike!

The Invisible Signs of Savannah

The Odonomy of Savannah II: The Case of the Invisible Signs

Savannah is well loved by this blogger for its active street frontage, its romantic buildings, its strangely abundant rows of townhouses (strange, that is, here in the South), its demure and pleasant gardens, and those redolent live oaks making the streets of the city beloved, well-shaded and well-lived. But among the things that I love about Savannah the most is what it doesn't have. Thanks Carfree and Eli for pointing out some missing items that should draw more attention to the elegance if Savannah's fine-grained street grid: the strange scarcity of stop signs and signalized intersections in this city.

To draw out my point better, I've decided to compare the First Ward of Charlotte, which has a typical downtown grid, with an equivalent area in the Historic District of Savannah. (Much of First Ward was formerly the Earle Village projects of the Charlotte Housing Authority, which is a well-known, early '90's Hope VI redevelopment that was among the first - and very successful - introductions of New Urbanism to Charlotte.) Below are images of the block pattern of First Ward and of Savannah's Historic District, each showing an area of exactly 1/4 square miles:

CHARLOTTE'S FIRST WARD (0.25 sq. mi.)




SAVANNAH'S HISTORIC DISTRICT (0.25 sq. mi.)



I should first mention that the street areas depicted in white above are the public rights-of-way only (I don't include internal drives). In the case of First Ward, I decided to include the present and future light rail right-of-way (which is part of the "transportation grid" and also creates/will create signalized intersections in the transportation grid; it is the north-south right-of-way corridor furthest to the left).

Charlotte's First Ward is relatively well-connected in terms of street connectivity and represents about the best we can hope for in most southern cities. With more development coming, the large meaty blocks (many are still surface parking lots) represent a lot of future revenue for our city. There are also only 40 intersections in the First Ward study area--much, much less intersections to control or maintain than Savannah. Savannah's study area, in contrast, has a whopping 203 intersections, more than five times First Ward's! But here is one surprise. First Ward has 16 signalized intersections (40% of its total intersections), while Savannah, in all that arabesque madness, only has 13 such intersections (6.5% of the total; these are located along the main east-west boulevards of Broughton, Oglethorpe and Liberty streets). Using Google Streetview I've counted all the intersection types for each study area. Here is the breakdown totals of intersection types for your reference:

Charlotte First Ward Intersections:
1 (2.5%) with a roundabout
16 (40%) with signalized stops
23 (57.5%) with at least one stop sign
40 Total Intersections

Savannah Historic District Intersections:
13 (6.5%) with signalized stops
51 (25%) with at least one stop sign
66 (32.5%) with only a yield sign
73 (36%) with no stop/yield signal or sign at all
203 Total Intersections

The majority, over two-thirds, of Savannah's public right-of-way intersections contain a yield sign or no sign at all. I wonder if such a remarkable feature can even be contemplated by Charlottean planners. Yes, the number above is right, folks, 36% of the Savannah Historic District public right-of-way intersections have no sign controlling intersection traffic! These "implicit yields" are controlled by the environment itself. Intuitively, we all recognize that a narrow and constricted entrance to an intersection with a wider street is a "stop" or "yield"--even if we don't see a sign. Everybody understands that the intersection of an alley with a street represents an implicit stop, just as everybody understands that you don't need a stop/yield sign at the end of your driveway. Savannah knows this and allows the intimate scales of its fine-grain environment to dictate traffic control. In reality, most of the yield signs are not really needed at all, much like yield signs are not really necessary for roundabouts. Traffic engineers just seem to want them there for liability reasons, but, so long as one understands the direction of traffic flow, Savannah's grid is so driver intuitive, that I'm probably right in saying that most drivers do not even register or think about the yield signage as they meander through the city grid.

Can you spot what is missing here? (Savannah Odonomy Series, no. 2)

View Larger Map

Just follow the cyclists and ride around the park. There are actually several elements missing present in most city grid streets. Warning. Neither Copenhagen nor Portland will be of much help to you here. There is one really obvious element missing (that I will base my next discussion on here). But you may find one missing element or two that I have not thought about. For now, just stay on the loop. Once you think you know the obvious element that is missing, branch out to the next parallel loop of surrounding streets (or alleys) and see another surprise.

The way I was taught to read "great design" in school was to start with what was missing. It always stunned me what other people observed about good design. I hope the same can be true of the blogosphere! Happy sleuthing.