Clarence Perry's Neighborhood Unit, one of the most influential diagrams in the history of urban design.

Ref:  Mehaffy, M. Porta, S. Romice, O. (2014), The "neighborhood unit" on trial: A case study in the impacts of urban morphology, Journal of Urbanism, International Research on Placemaking and Urban, in print.

Link to paper

The organization of modern city planning into “neighborhood units” – most commonly associated with the Clarence Perry proposal of 1929 – has been enormously influential in the evolution of modern city form, and at the same time, has also been the subject of intense controversy and debate that continues to the present day. New issues under debate include social and economic diversity, maintenance of viable pedestrian and public transit modes, viability of internalized community service hubs, and efficient use of energy and natural resources, including greenhouse gas emissions. We trace the history of this controversy up to the present day, and we discuss new developments that may point the way to needed reforms of best practice.