Page "Cul-de-sac" Paragraph 55

In the North American development context and planning literature, cul-de-sac streets have been associated with low density residential development which is judged as inefficient by sustainable development theorists and proponents.

The increased prevalence of cul-de-sac streets occurred in the 1960s and ' 70s, a period of rapid economic and city expansion, when a detached house on a large lot meant an ideal form of habitation ; overlooking the potential negative externalities.

This temporal coincidence of the wide adoption of a street type and an increasing demand for large lots and houses creates the impression of a necessary relationship between street type and unit density.

Historically, however, the earliest systematic application of the cul-de-sac street type by Raymond Unwin ( 1909 ) had a unit density between 8 and 12 units per acre, considerably higher than mid-to-late 20th century.

Even early 21st century developments rarely achieve densities above 5 to 7 units per acre in the suburbs.

Conversely, early 1950s suburban developments that were laid out on a grid exhibit similar low densities.

Evidently, street, network type and density are not linked causally ; other factors, such as land scarcity and income influence the outcome as, for example, in cities that are landlocked or that have low average incomes.