An Odonomy of Savannah, Part V: Loading Streets and Avenues--the First Division
Before we can understand the interesting jazz of Savannah’s streets, we need to first master a few necessary chords. We need to first discern her vamps and primary riffs. We will then be able to see how she breaks from them and how she improvises her music.
|Savannah's "Loading Streets"|
What creates the distinction between loading streets and avenues is the fact that most parcels want to front the same streets. Human-beings, being commercial and civic creatures, like to concentrate access to lots on the same public streets. This tendency creates well ordered street fabrics and also churns out higher real estate values. Why? The value of the frontage is a result of the fact that the middle parcels of most blocks can only be accessed from a chosen side of their block. Thus, block subdividers typically favor the loading grain of the most important adjacent street. This puts the access to at least half of the lots in their blocks at the important frontage side, where they are most likely to capture more eyes and potential customers/users. Another way to look at the value of favoring the nearby loading grain is to realize that when adjacent uses have access points on the same street, the travel time of users traveling between them decreases. A greater diversity of destinations of nearby uses within closer distance to each other reinforces the overall value of their street’s frontage. We may not be cognizant of the hidden economic and very rational reciprocating choices behind our drive to create and perpetuate loading grains in the grid fabric (although individuals obviously intuit it), but we create cities this way because of our social intelligence. A lot about city form is realizing that much of productive human activity is a collective phenomenon that may escape the notice of most of its individual agents. Such beautiful creatures we are.
Loading streets tend to travel along the long dimensions of the blocks. It makes sense that blocks want to be long in the loading grain direction as that loading frontage is value and avenues have less direct access to uses. Thus, minimizing the avenue side dimension of blocks makes sense for land use efficiency and infrastructure investment purposes. But I think the block short dimension also represents an advantage in itself. Avenues increase the overall value of the grid network. Their shorter segments mean they intersect more often with loading streets and thus produce the global economic advantage of the grid gained from connectivity. Sometimes, they also use this connectivity value to increase value to themselves. They actually create higher pedestrian activity and related real estate value on their abutting parcels especially when certain geographic and geometric conditions are in play. Both Bull Street in Savannah and Manhattan’s Fifth Avenue are avenues that powerfully attract activity and offer real estate advantages for similar—but also different—reasons that are instructive to me.
Yes, by the way, even city grids composed of perfect squares have dominant loading grains. They always do. In such places, as in downtown Portland, the greater geography and geographic features, such as grade change and water frontage, and important internal features, such as linear parks, help create the dominant direction of the loading grain in subareas (although, the direction of that grain is prone to change, subarea to subarea, more often in these open fabrics).
Because every use in the suburb needs to cater to vehicular access, any of the street patterns that create the suburb stem from underlying, locally-focused, proforma-driven imperatives to maximize the loading condition. An avenue type of street is just a waste of infrastructure for subdivision designers. A cul-de-sac, not coincidentally, is a loading street by default, and, in fact, it is the utter maximum condition for the loading of uses unto a street, an accommodation to the fact that cul-de-sac residents do not have an economic advantage to maximize access to their homes (making internal avenues unnecessary); in fact, the economic advantage goes the other way. Even though some collector streets in a subdivision have to be avenues (or avenue/loading street hybrids), the residential suburb detests the avenue.
In part because of that suburb many of us have grown up in, loading streets are what most people have in mind when they think of a street, so much so that we may miss the network utility of the humble avenue, if indeed we are even aware of it as a distinct type. I certainly did not think about the urban avenue much before I got really acquainted with Savannah’s historic grid. New Urbanists are no exception to this tendency either. Judging from their default donut block plans and default street typicals, New Urbanists love maximizing the loading condition as well.
The avenue is the most urban of streets. In my next post, we will get more acquainted with this stranger who quietly serves us. This humble, utilitarian street type has many strengths. It is a street type that tends to be neglected by planners. It is not often as stately as the Main Street or the Boulevard. It is not as intimate or human scaled as the rear-yard alley. But the Avenue is the workhorse street of the grid. It provides the cross-bracing and the hanging threads of the structure. As you can probably tell by now, I like it a lot.