defensible space
The defensible space theory of architect and city planner Oscar Newman encompasses ideas about crime prevention and neighborhood safety. The theory developed in the early 1970s, and he wrote his first book on the topic, Defensible Space in 1972. The book contains a study from New York that pointed out that higher crime rate existed in high-rise apartment buildings than in lower housing projects. This, he concluded, was because residents felt no control or personal responsibility for an area occupied by so many people. Throughout his study, Newman focused on explaining his ideas on social control, crime prevention, and public health in relation to community design.

Principles

Oscar Newman’s basic five principles of designing defensible space as quoted in Design Guidelines for Creating Defensible Guidelines are as follows:

1. The assignment to different resident groups the specific environments they are best able to utilize and control, as determined by their ages, life-styles, socializing proclivities, backgrounds, incomes, and family structures.
2. The territorial definition of space in residential developments to reflect the zone of influence of specific inhabitants. Residential environments should be subdivided into zones toward which adjacent residents can easily adopt proprietary attitudes.
3. The juxtaposition of dwelling interiors with exterior spaces and the placement of windows to allow residents to naturally survey the exterior and interior public areas of their living environments and the areas assigned for their use.
4. The juxtaposition of dwellings—their entries and amenities—with city streets so as to incorporate the streets within the sphere of influence of the residential environment.
5. The adoption of building forms and idioms that avoids the stigma of peculiarity that allows others to perceive the vulnerability and isolation of a particular group of inhabitants.

To create a defensible space community, residential areas should be subdivided into smaller entities of similar families because control is enhanced. Responsibility for the area is more easily assumed in a smaller group of families as opposed to a larger community. Smaller groups more frequently use an area geared toward them. The number of activities in the space is increased; thus, a feeling of ownership and a need to protect the property follows. On the other hand, when larger groups use a community space, no one has control over the area, and an agreement over its acceptable uses is often in dispute.

http://en.wikipedia.org/wiki/Defensible_space_theory