elements of city planning

ELEMENTS OF MEGALOPOLITAN DESIGN FROM FIFTH WARD SERIES

FOUR ELEMENTS OF MEGLOPOLITAN DESIGN. The inner city street infrastructure will be reorganized around the four principal elements shown in the diagram above and described in the paragraphs below.

1. SWITCHES. The analysis of urban infrastructure begins, not with the line of connectivity which indicates a path or street, but with the isolated point.  The point is taken from existing street intersections that are redefined as “switches” or nodes in a large network of streets. Switches exist in one of five distinct states. The first state is marked as a 1-way switch indicating one spoke connecting to and from it. This is the abstraction of a dead end street. The following switches indicate the successive number of edges or spokes connecting to and from it marked as 2,3, and 4-way switches. With an increase in number comes an increase in the openness or continuity of the infrastructure. A final switch type is the null switch which is an unbuilt or demolished intersection. 

2. MAT (VOIDS). The second element of urban organization is a plane or mat. The mat marks basic programmatic divisions of the ground plane and so resembles a typical zoning map. In the New Town the mat represents program but can also take on other meanings and associations. For example, programs dominated by space such as parks, abandoned lots and industrial areas are grouped together in the plan to form a larger mat that represents the void spaces. Other mat associations mark distinctions between zoned/unzoned, vegetated/barren, owned/shared, and full/empty. These associative uses are meant to break down tyranny of single-use zoning.

3. SUBGRID. The third element represents the smallest scale of urban organization. In the new Fifth Ward plan, the scale of the “street” pattern is similar to that of a traditional city block, measuring around 250’ to a side. Providing some of the amenity of the traditional urban grid, the street pattern is highly fragmented and need not provide the overall structure for any of the subdivided districts. The subgrid works symbiotically with a higher levels of organization superimposed upon it. As the first level of the Street Hierarchy, the subgrid is conceived as a changeable mesh of orthogonal interconnections. It is given over to small scale “informal” development in that is not typically designed by architects. As a malleable grid — a gravel bed — it can take anything that a speculator, bureaucrat or an owner builder can throw at it. It provides minimum infrastructure.

4. UNIT OF AGGREGATION. The fourth element of urban organization is the second level of the Street Hierarchy taking the place of what planers call a "collector." It structures one or more subgrids into a tentative whole becoming a “unit of aggregation” amongst other formally related units. Like most cities, Megalopolis is aggregated from a basic unit. Unlike traditional cities, however, the specific unit of aggregation is not a “block.” Following the ever increasing economies of urban scale, the basic unit is an organizational spine structuring a complex assembly of inhabitable space, technical services, street infrastructure and public utilities. This unit of aggregation is capable of an infinite number of configurations whose share three key characteristics. The first characteristic is to create neither a figure nor a field condition but to mediate between the two. This characteristic stems from the desire to reproduce a city that is dominated by space rather than form. The second characteristic of the spine unit is that it organizes subgrids not as a block or a superblock, from the outside in, but from the center out. This characteristic stems from our aversion to frame or contain megalopolitan space by form of any sort. Contemporary urban space grows from its locus which does not close off its edge. The third characteristic of the spine unit edge is that it ties the local levels of urban organization to the greater whole. If a city is defined as that which exceeds the sum of its parts, then the spine unit forms the crucial role as the agent of an overall megalopolitan aggregation.