Fused Grid - The Fused Grid Model

The Fused Grid Model

Based on these sets of issues, the identified advantages of alternative patterns and the ideas of 20th century theorists, the Fused Grid assembles several elements from these precedents into a complete stencil. Just as the grid stencil and the Radburn pattern did, it sets up a geometric structure that exhibits the key characteristics of a functioning system. It consists of a large-scale open grid of collector streets, carrying moderate speed motorized traffic. This grid forms precincts (quadrants, neighbourhoods) that are normally about 16 ha (40 acres) in size (400 m by 400 m). Within each precinct, the layout uses crescents or cul-de-sacs or a combination of both to eliminate through traffic. In addition, a continuous open-space and pedestrian path system provides direct access to parks, public transit, retail and community facilities. Residents can cross a quadrant block on foot in about five minutes. The most intensive land uses such as schools, community facilities, high-density residential uses, and retail are located in the center of the plan, reached by twinned roads which connect longer, district destination points.

This synthesis of inherited network traditions and ideas is accomplished through the application of two practical means: a rectilinear, orthogonal geometry, a key characteristic of the grid, and the use of two street types that have generally been associated with the Radburn-type subdivisions.

The orthogonal geometry serves two purposes: a) to enhance the navigability of the network structure particularly at the district and regional scale. This is important at car speeds where decisions about destinations and turns have to be made promptly. b) to maintain a good level of safety at road intersections, as recommended by traffic engineering manuals. The grid’s second essential characteristic, connectivity, is recaptured through a third element that completes the “system” – pedestrian-only connectors between regular streets that are intended for all movement modes. These connectors (paths) are typically routed through open spaces that occupy central points in a neighbourhood cell. Thus the neighbourhood street network comprises a mixture of streets; some pedestrian dominant and others car dominant. A fourth element is the nested hierarchy of streets that distinguishes between connectivity and permeability at the neighbourhood level. This idea reflects the fact the longer the linked destinations the higher the level of mobility must be. A dendrite configuration, such as a river, takes progressively wider expanses of land to accommodate the flow. A nested hierarchy on the other hand distributes the flow at each volume level to alternative paths. The complete system, though it may appear unfamiliar, is composed of entirely familiar and extensively used elements in contemporary development.