Kevin Lynch made a case for what he called normative planning to be considered equally with decision theory and functional planning theroy. He illustrated that city form could be understood as a sequence or pattern of districts, edges, nodes and paths. This typology encouraged physical designers to master plan neighborhoods and towns in ways that provided these structural features. Others added the threashold or portal as another elemental building block of positive urban form.

We have made progress since Lynch wrote in the 1970's but most contemporary planning continues to disappoint designers and citizens. More recently, Adnres Duany, Elizabeth Plater-Zybek, Peter Calthorpe, Randolph Hester and other have advanced the practice of community master planning. The material below draws heavily from these sources.

The basic elements of urban development are the neighborhood, district and corridor.

• Features a center and an edge
• Mix of activities
• Optimal size - 1/4 mile radius
• Composed of blocks within a network of streets
• Priority locations are dedicated to public space

According to Randy Hester, the ideal population of a neighborhood ranges from 5,000 to 7,000 people. The neighborhood should be separated from adjacent neighborhoods by open space buffers 100 to 1,500 feet wide. The neighborhood can support about 150,000 square feet of commercial space.

Hidden Springs is an example of a planned community established as a planned unit development 10 miles northwest of Bosie. The remote location is clearly a detriment to the sustainabilty goals of the community. The developer initiated a program to reduce the vehicle trips per day. This has achieved 8 trips per day compared to 10.5 which is typical for single use low density residential neighborhoods.

Functionally specialized, such as a campus, air ports, etc. Except where uses are truly incompatible, single use districts should avoided in favor of mixed use.

Connector of neighborhoods and districts

May form the edge of neighborhoods and districts

Includes wildlife corridors and public transit alignments

The plan at left is over-laid on an aerial photo of the larger landscape. Enlarge the image and study the relationship between the regional drainage system and the corridors. They form the edges of the neighborhoods while providing wildlife habitat and recreation opportunities.

These corridors are the green infrastructure assisting the stormwater treatment necessary after the site is made more impermeable by roads and roofs. Using an landscape ecology approach as a means to generate urban form is discussed in detail by Charles Waldheim. The structural elements of the natural landscape are the matrix, patch, corridor and network. For more information see the ecology link on this web site.

The two schematic designs presented at left summarize neighborhood and village design principles refined by DPZ. Enlarge and study this plan.

Square Block at Norton Commons- perimeter platting creates a street wall perforated with inlets to the parking area in the center. (DPZ, 2007)

The second image at left is a built example of a viriety of housing types for higher densit y living. Enlarge the image and study each type. Notice the use of the Square Block pattern where parking is at the center of the block.

Traditional platting in the United States was based on the 50' module. This allowed 25' townhouses and store fronts. Multiples of the unit were made residential lots. However, the traditional subdivision unit results in inefficient land use since the double row parking lot requires 64' of with. Dividing 64' by four results in a planning subdivision unit of 16' which in the minimum width of a row house and allows for one car and room for a pedestrian to pass.

Using the 16' module for a complete building envelope or multiples of it, four building types are common and result in efficient parking function. The courtyard building is the most urban of the types. The open space is partly or completely enclosed by the building rectangles (rods).

The side yard building type requires a 32' lot width. It responds to the need to orient buildings for passive solar heating or natural day lighting.

The rear yard building type places the structure on the front the lot making the rear of the lot available for parking or accessory buildings. The type is useful for town houses with a garden or outbuilding as well as for modest retail or office uses.

The fourth building type is the perimeter yard building. This is the most suburban with building setbacks on every side. It provides for a semi-public front yard. The impact of the buildings and landscape is compromised by automobiles a front driveway or garages that extend in front of the building facade. The diagrams show positive garage and parking configurations.

Civic, transportation buildings and some manufacturing uses require exemptions from the 16' module.