Environmental Design Circular

Crime Prevention Through Environmental Design Circular

The term Crime Prevention Through Environmental Design (CPTED) is used to describe a series of physical design characteristics that maximize resident control of criminal behavior within a residential community. A residential environment designed under CPTED guidelines clearly defines all areas as either public, semiprivate, or private. In so doing, it determines who has the right to be in each space, and allows residents to be confident in responding to any questionable activity or persons within their complex. The same design concepts improve the ability of police to monitor activities within the
community.

The CPTED premise is that the proper design and effective use of public and private space can lead to a reduction in the incidence and fear of crime, reduction in calls for police service and to an increase in the quality of life within a community.

CPTED Strategies

Natural Surveillance

Surveillance is a design concept directed primarily at keeping intruders under observation. Therefore, the primary thrust of a surveillance strategy is to facilitate observation and to accomplish the effect of an increased perception of risk. Surveillance strategies are typically classified as organized (e.g., police patrol) mechanical (e.g., lighting) and natural (e.g., windows).

Natural Access Control

Access control strategies are typically classified as organized (e.g., guards), mechanical (e.g., locks), and natural (e.g., spatial definition). This lesson plan outline will concentrate on the third strategy of natural access control. The primary thrust of an access control strategy is to deny access to a crime target and to create a perception of risk in
offenders.

Territorial Reinforcement

The concept of territoriality suggests that physical design can contribute to a sense of territoriality. That is, physical design can create or extend a sphere of territorial influence so potential offenders perceive that territorial influence. For example: low walls, landscape and  paving patterns to clearly define the space around a unit entry as belonging to (and the responsibility of) the residents of that unit.

Provide clear border definition of controlled space (e.g., fences, hedges, paving patterns and low walls). Avoid unassigned space. As much as possible, all space should become the clear responsibility of someone. Provide clearly marked transitional zones that indicate movement from public to semiprivate to private space. For example, the sidewalk represents public space and the main path into a residential development is semiprivate, and a path that branches to an individual unit(s) becomes semiprivate and the interior of the unit becomes  private space. Relocate gathering areas to locations that provide natural surveillance and access control, as opposed to locations away from the view of would-be offenders.

For example, all play areas should be located within the central common area of the building with as many units as possible able to glance or actively watch children at play. Place safe activities in unsafe locations to create the natural surveillance of these activities to increase the perception of safety for legitimate users and risk for offenders. For example, well-used common areas (safe) may overlook a parking area  (unsafe) to provide additional security for the parking area.

Place unsafe activities in safe locations to overcome the vulnerability of these activities with natural surveillance and access control of the safe area. For instance, common toilet facilities and laundry rooms should not be located in a remote corner of the site or at the end of a long nameless hallway. Locate these facilities (unsafe) adjacent to the entry or location where there is normally high foot traffic (safe). Improve scheduling of space to allow for effective use. Redesign or revamp space to increase the perception or reality of natural surveillance. Overcome distance and isolation through improved communications.

Design Recommendations

Natural Surveillance/Visual Connection

Provide an opportunity for people engaged in normal everyday activity to observe the space around them. Place activities where individuals engage in those activities so they become part of the natural surveillance system without interruption to their
activity. Provide a good “visual connection” between residential and/or commercial units and public environments such as streets, common areas, parks, sidewalks, parking areas and alleys. Place actively used rooms such as kitchens, living/family room and lobbies to allow for good viewing of parking, streets and/or common areas. Managers, attendants and security personnel should have extensive views of these areas. Provide for the ability to see into a room or space prior to entering. Take advantage of mixed use if it exists and provide good “visual connection” between uses. This may enable natural surveillance during the day and evening, (i.e., a commercial zone that becomes vacant in the evening or a residential zone that is uninhabited during the day).

Natural Access Control/Spatial Definition

Locate common areas as centrally as possible or near major circulation paths within the project. Avoid remote locations for common areas. Consider containing common areas within a building layout. Group common areas together so that necessary tasks such as laundry may be  done while watching children or using recreation areas. Provide clear well-lit paths from the street to the development through all parking  and landscape areas, and within the development to building entries. Avoid indistinct walkways and entries where occupants and guests  may become “lost or disoriented” or must search for the correct entry or unit. Provide adequate lighting, width of path, definition of path  and ability to see a destination. Provide obvious physical security techniques such as locks, lights, walls, gates and security signs.

Control unwanted entry through attic space. Where ownership changes, provide a wall that extends from the suspended ceiling to the underside of the roof/floor assembly above. Identify whether surrounding property has a negative or an adverse impact on the  development. Mitigate the adverse impact whenever possible with enhanced access techniques. Ground floor units may require security  above and beyond the other areas in the development. Walls, fencing, deterrent landscaping and lighting may be necessary.

Territorial Reinforcement/Fostering A Sense of Ownership

People take more interest in something they own or feel they are intrinsically involved. Therefore, the environment should be designed to clearly delineate private spaces.  Provide obvious defined entries, patios, balconies and terraces. Use low walls, landscape and paving patterns to delineate ownership and responsibility. Create a sense of ownership to foster behavior that challenges abuse or unwanted acts in that space. People who have a vested interest are more likely to challenge intruders or report them to the police. Provide real amenity in common areas so people will use them and have a stake in maintaining them. Provide clearly defined and secure storage areas. Consider creating areas within a project where people share clustered parking, entries, amenities and common areas. Avoid long corridors that are shared by all and owned by no one.

Facilitate Neighborhood Watch programs by clustering units in such a way to allow occupants to interact and see unit entries (and possibly sidewalks and streets) from within their units. Create an environment where strangers or intruders stand out and are more easily identified. In some developments it may be appropriate to give occupants some autonomy and control over their environment. This may include devoting landscape space to tenant use and upkeep, allowing occupants to determine color, landscape and other design materials.

Landscaping and fencing

Specify thorny plants and landscape to create a natural barrier and to deter unwanted entry. Specify vines or planted wall coverings to deter graffiti. Avoid blank spaces that may be an invitation to graffiti vandals. Provide landscape and fencing that do not create hiding places for criminals. Discourage crime by creating an inhospitable environment for criminals. Provide attractive and durable masonry or fencing whenever possible. Consider creative solutions to fencing schemes that work aesthetically as well as functionally.

Lighting

Provide lighting systems that provide nighttime vision for motorists to increase the visibility of pedestrians, other vehicles and objects (that should be seen and avoided). Provide lighting systems which provide nighttime vision for pedestrians, homeowners and business people to  permit pedestrians to see one another, to see risks involved in walking at night and to reduce the risk of trip-and-fall accidents. Provide  lighting systems that will enhance police ability for surveillance, patrol and pursuit. Provide lighting systems that minimize glare, light and  pollution and light trespass. Where necessary, provide light transition zones.

The CPTED information included in this tip of the month was compiled from information obtained from the City’s Design Out Crime Task Force and the Crime Prevention Unit, Community Relations Section. The Department does not propose CPTED or any other
single technique as a cure-all for crime in the community. Nonetheless, experience strongly suggests that application of CPTED in combination with other Department crime prevention programs will help reduce crime and fear of crime in the community.

For Release 3:20 pm PST
January 31, 2000