page_title: Fused grid
section_title: Defence, aesthetics, and adaptability
hierarchical_section_title: Fused grid / Criticisms of the prevailing network patterns / Defence, aesthetics, and adaptability
caption_attribution_description: English: A straight street in a 1950s suburb showing low density single family detached housing, wide Right of Way, and generous set backs from the property line.
context_page_description: The fused grid is a street network pattern first proposed in 2002 and subsequently applied in Calgary, Alberta and Stratford, Ontario. It represents a synthesis of two well known and extensively used network concepts: the "grid" and the "Radburn" pattern, derivatives of which are found in most city suburbs. Both concepts were self-conscious attempts to organize urban space for habitation. The grid was conceived and applied in the pre-automotive era of cities starting circa 2000 BC and prevailed until about 1900 AD. The Radburn pattern emerged in 1929 about thirty years following the invention of the internal combustion engine powered automobile and in anticipation of its eventual dominance as a means for mobility and transport. Both these patterns appear throughout North America. "Fused" refers to a systematic recombination of the essential characteristics of each of these two network patterns.
context_section_description: The first known criticism of the grid was put forward on the grounds of defence that became irrelevant following the prevalence of the cannon (1500s). Aristotle argued that the old maze-like street pattern which preceded the grid, made it difficult for invading troops to find their way in and out of the city, Alberti also expressed the same view 1500 years later and added the advantage of a superior visual effect of the organic pattern over the grid.
  A second criticism was put forward most forcefully by Camillo Sitte on aesthetic grounds. He argued that grids lack variety and, consequently, are uninteresting and can become oppressive by their monotony. This argument has been undermined first by the potential variety of grid dimensions that can be used in combinations such as appear in many city plans. More importantly, ground observation of cities shows that the mix of buildings and their varied street alignments as well as open spaces with their size variations coupled with constant redevelopment, suppress the monotony of the grid. Nonetheless, 20th century planners shunned pure grids and implicitly endorsed C. Sitte's ideas on the need for a picturesque streetscape. This tendency is generally based on an intuitive aesthetic ground; that people dislike long open street vistas and prefer those that terminate. Recent subdivision or town layouts such as Poundbury(1993), Seaside(1984) and Kentlands(1995) consciously avoided the homogenous grid and its open vistas. 
  A further criticism of the grid focuses on its unsuitability for uneven, variegated terrain. Its application in sites such as Priene (350 BC), Piraeus (circa 400 BC), San Francisco (1776), Saint John, NB (1631) and others severely limits general accessibility by inadvertently introducing steep slopes or, in certain cases, stepped road sections and creates construction difficulties. In cities with intemperate climates this limitation is accentuated. Moving in a straight line uphill becomes arduous or, occasionally, impossible, particularly for non-motorized wheeled means of transport.
  A Radburn-type network inherently includes a variety of city blocks and terminating vistas and, consequently, pre-empts criticism centered on monotony and lack of end-closure. Its unconstrained geometry adapts easily to topographical irregularities and geographical features such as streams, woodlots and natural ponds. As neither the alignment nor the length of neighbourhood streets need to remain constant, this model gives planners considerable latitude in laying out a network.
  Two newer aesthetic criticisms of the Radburn model emerged in the 1980s: the absence of a street "wall" or "enclosure" and the repetitiveness of housing unit forms as found in suburban districts. Both these criticisms can be understood as a misapplication of aesthetic norms on socio-economic outcomes. The spaciousness of housing developments at the city's edge echoes the spaciousness of contemporary houses and are both driven not by aesthetic intent but by economic prosperity. Judging the visual outcome of prosperity using historic streetscape criteria of cities with a different socioeconomic makeup would make the verdict predictable and practically meaningless.
  Moreover, the "street wall" and "enclosure" criticism of the Radburn pattern applications are undermined by observation of city districts new and old. Close examination would reveal that these spatial qualities are inextricably linked to housing unit and population density as well as construction technology and are not necessarily the outcome of a street pattern: The higher the habitation density of the street (and town) the closer and taller the buildings have to be to accommodate more people. A street pattern does not induce either unit density or the visual wall effect. For example, in earlier cities with labyrinthine street layouts, analogous to some contemporary suburban districts, residential buildings were agglutinated creating an entire perimeter wall around the city block with few perforations for reasons of security, safety and a heightened 
caption: A straight street of a grid pattern in a 1950s suburb exhibiting low density, single family detached housing
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