A space that has territorial markers, opportunities for surveillance, and clear indications of activity and ownership.
Defensible spaces are used to deter crime. A defensible space is an area such as a neighborhood, house, park, or office that has features that convey ownership and afford easy and frequent surveillance. These features allow residents to establish control over their private and community property, and ultimately deter criminal activity. There are three key features of defensible spaces: territoriality, surveillance, and symbolic barriers. id="footnote56a"> class="nounder totri-footnote" href="https://www.safaribooksonline.com/library/view/universal-principles-of/9781592535873/xhtml/ch29_fn.html#footnote56">1
Territoriality is the establishment of clearly defined spaces of ownership. Common territorial features include community markers and gates to cultivate a community identity and mark the collective territory of residents; visible boundaries such as walls, hedges, and fences to create private yards; and privatization of public services so that residents must take greater personal responsibility and ownership (e.g., private trash cans instead of public dumpsters). These territorial elements explicitly assign custodial responsibility of a space to residents, and communicate to outsiders that the space is owned and protected.
Surveillance is the monitoring of the environment during normal daily activities. Common surveillance features include external lighting; windows and doors that open directly to the outside of first-floor dwellings; mailboxes located in open and well-trafficked areas; and well-maintained courtyards, playgrounds, and walkways that increase pedestrian activity and casual surveillance. These features make it more difficult for people to engage in unnoticed activities.
Symbolic barriers are objects placed in the environment to create the perception that a person’s space is cared for and worthy of defense. Common symbolic barriers include picnic tables, swings, flowers, and lawn furniture—any symbol that conveys that the owner of the property is actively involved in using and maintaining the property. Note that when items that are atypical for a community are displayed, it can sometimes symbolize affluence and act as a lure rather than a barrier. Therefore, the appropriateness of various kinds of symbolic barriers must be considered within the context of a particular community. id="footnote57a"> class="nounder totri-footnote" href="https://www.safaribooksonline.com/library/view/universal-principles-of/9781592535873/xhtml/ch29_fn.html#footnote57">2
Incorporate defensible space features in the design of residences, offices, industrial facilities, and communities to deter crime. Clearly mark territories to indicate ownership and responsibility; increase opportunities for surveillance and reduce environmental elements that allow concealment; reduce unassigned open spaces and services; and use typical symbolic barriers to indicate activity and use.