Defensible space is a model for residential environments which inhibits crime by creating the physical expression of a social fabric that defends itself. All the different elements which combine to make a defensible space have a common goal—an environment in which latent territoriality and sense of community in the inhabitants can be translated into responsibility for ensuring a safe, productive, and well-maintained living space. The potential criminal perceives such a space as controlled by its residents, leaving him an intruder easily recognized and dealt with. On the one hand this is target hardening—the traditional aim of security design as provided by locksmiths. But it must also be seen in another light. In middle-class neighborhoods, the responsibility for maintaining security has largely been relegated to the police. Upper-income neighborhoods—particularly those including high-rise apartment buildings—have supplemented police with doormen, a luxury not possible in other neighborhoods. There is serious self-deception in this posture. When people begin to protect themselves as individuals and not as a community, the battle against crime is effectively lost. The indifferent crowd witnessing a violent crime is by now an American cliché. The move of middle- and upper-class population into protective high-rises and other structures of isolation—as well guarded and as carefully differentiated from the surrounding human landscape as a military post—is just as clearly a retreat into indifference. The form of buildings and their arrangement can either discourage or encourage people to take an active part in policing while they go about their daily business. “Policing” is not intended to evoke a paranoid vision but refers to the oldest concept in the Western political tradition: the responsibility of each citizen to ensure the functioning of the polis.
“Defensible space” is a surrogate term for the range of mechanisms—real and symbolic barriers, strongly defined areas of influence, and improved opportunities for surveillance—that combine to bring an environment under the control of its residents. A defensible space is a living residential environment which can be employed by inhabitants for the enhancement of their lives, while providing security for their families, neighbors, and friends. The public areas of a multi-family residential environment devoid of defensible space can make the act of going from street to apartment equivalent to running the gauntlet. The fear and uncertainty generated by living in such an environment can slowly eat away and eventually destroy the security and sanctity of the apartment unit itself. On the other hand, by grouping dwelling units to reinforce associations of mutual benefit; by delineating paths of movement; by defining areas of activity for particular users through their juxtaposition with internal living areas; and by providing for natural opportunities for visual surveillance, architects can create a clear understanding of the function of a space, and who its users are and ought to be. This, in turn, can lead residents of all income levels to adopt extremely potent territorial attitudes and policing measures, which act as strong deterrents to potential criminals.