Over the last few years, I have noticed a resurgence of "Crime Protection Through Environmental Design" (CPTED). The term was originally coined by Dr. C. Ray Jeffery in his book of the same title nearly 20 years ago. The book deals with the assumption that proper design and effective use of the environment can lead to a reduction in the fear and incidence of crime, and to an improvement in the quality of life. The concept was described by Oscar Newman, an Architect, in his 1972 work "Defensible Spaces: Crime Prevention Through Urban Design", which was a study commissioned by the National Institute of Justice.
The CPTED Program
As you can see, CPTED is an approach to security design that has been around for a while. When CPTED was originally proposed, crime and fear of crime weren't nearly as prevalent as they are today. The renewed interest is gratifying to a security designer, because there is now increased emphasis on using CPTED methods to design facilities that work to limit criminal activity. CPTED has been acknowledged by such organizations as the National Association of Convenience Food Stores, the American Society for Industrial Security, the American Institute of Architects and the National Association of Urban Planning Educators. The State of Florida and Virginia have passed laws that require review and implementation of CPTED techniques to reduce crime and cost. The National Crime Prevention Institute provides one and two week courses on the subject that are excellent opportunities to initiate a team approach to CPTED, even for the corporate business person.
The basic concept of CPTED is that the physical environment can be changed to impact criminal behavior in a way that will reduce the incidence and fear of crime and improve the quality of life. In a CPTED approach, a given design will impact on criminal activity if analysis and implementation of the four overlapping strategies, access control, surveillance, activity support and motivation reinforcement are included. While most security professionals are familiar with the first two terms, their knowledge is usually limited to the more traditional aspects of using hardware and outside personnel for these purposes (alarms, locks, card readers, guards and CCTV). These traditional access control and surveillance methods emphasize the use of mechanical and organized crime prevention techniques while overlooking, minimizing or ignoring attitudes, motivation and the use of the physical environment to achieve the same goals. The CPTED concept uses natural opportunities presented by the environment to impact crime in a positive manner. The concepts of activity support and motivation reinforcement suggests that the physical design of a facility can create or extend a range of influence that gives the occupants or users of the space a sense of ownership, and that potential criminals can sense that ownership and be dissuaded from committing a crime because of the perceived increase in risk to being observed, caught and punished.
Access control is primarily directed at decreasing criminal opportunity. In essence, it operates to keep unauthorized persons out of a particular location if they do not have a legitimate reasons for being there. In its most elementary form, some access control can be achieved in individual dwelling units or commercial establishments by the use of adequate locks, hinges, doors and window barriers (known as target hardening). However, when one moves beyond private property to public or semi public spaces, the application of access control becomes much more complicated. Lobbies of apartments, office buildings, or schools are often open the public, and to those willing to commit criminal acts if the opportunity arises. The traditional solution to this type of problem is normally to station guards at entrance points to screen visitors.
The problem is most acute on streets and similar areas that are entirely open to public use. In some areas, such as neighborhoods composed of tightly knit ethnic groups, the streets are effectively denied even to certain non-criminal outsiders by the imposition of social barriers. However there are other, more legitimate techniques for limiting access in areas normally open to the public. Physical barriers imposed by natural forms (e.g., rivers and lakes), existing manmade forms (e.g., railroad tracks, parks, vegetation, highways, cemeteries), and artificial forms designed expressly as impediments (e.g., street closings, fences), serve to restrict movement.
Many criminals also display various environmental preferences, both physical and social, that can be frustrated by the creation of psychological barriers. These barriers may appear in the form of signs, parkways, hedges, etc., or anything that announces the integrity and uniqueness of an area. The hypothesis operative in creating psychological barriers is that if a target seems alien, mysterious, or difficult, it may also be unattractive to the potential criminal. As a paradox, the hypothesis can work when areas, by their clear legibility, transparency, and directness, discourage the potential offender because of users' familiarity with each other and the surroundings, and the visible absence of places to hide or conduct criminal acts.
Because any strategy that fosters access control is also likely to impact on egress, careful consideration should be given to access control strategies. Such strategies may not only limit the egress of the criminal, but hinder the mobility of the potential victims.
Although similar to access control in some respects, the primary aim of surveillance is not to keep intruders out (although it may have that effect) but, rather, to keep outsiders under observation when they are inside the defensible space. Surveillance increases the perceived risk to offenders, and the actual risk if the observers are willing to act when potentially threatening situations develop. A distinction can be made between organized surveillance and natural or spontaneous surveillance.
Organized surveillance is usually carried out by police or hired guard patrol in an attempt to project to potential offenders the impression that police surveillance is highly likely at a given location. The effectiveness of this particular technique may vary greatly with geographic considerations, crime specific factors, and the efficiency of the security personnel themselves. The trend toward community policing is increasing spontaneously, and the spread of such indicators might prove a potentially important. In some instances, surveillance can be achieved by non-human techniques such as closed-circuit television (CCTV) or alarms. Some success has been achieved in certain residential complexes where the CCTV surveillance channel can be dialed on the residents' individual sets; this medium provides an additional window on the world and even serves to promote social interaction.
Natural surveillance can be achieved by a number of design techniques, such a channeling the flow of activity to put more observers near a potential crime area, or creating a greater observation capacity by such design techniques as installing windows along the street side, enclosing a staircases with glass, or using single-loaded corridors. The technique of defining spaces can also convey a proprietary sense to legitimate users, inducing a territorial concern, which overlaps with the design concept of (victim) motivation reinforcement.
The general design concept of activity support involves methods for reinforcing existing or new activities as a means of making effective use of the built environment. This design concept originates in the observation that in a given community, resources capable of sustaining constructive community activities are often underused. Support of these activities can bring a vital and coalescing improvement to the community, along with a reduction of the vulnerable social and physical gaps that permit criminal intrusions. Such an approach might focus on a geographic area (e.g., block, neighborhood, city sector), a target population (e.g., vulnerable elderly victims, opportunistic youthful offenders) or an urban system (e.g., health delivery, transportation, zoning).
CPTED implements this concept by locating playgrounds where the children's parents can observe them at play, by placing reading or activity rooms near a building entrance, or by designing attractive mini-malls to foster constructive social activities.
In contrast to the more mechanical concepts of access control and surveillance, that concentrate on making criminal behavior more difficult, motivation reinforcement seeks not only to affect criminal behavior relative to the built environment, but to affect criminal motivation by increasing the risk of apprehension and by increasing the potential criminals' involvement in and identification with the physical and social environment that may be the object of criminal activity. This concept also emphasizes positive motivation reinforcement of the community in general by increasing territorial concern, social cohesion, and general sense of security. As it relates to the CPTED approach, behavioral science is in a developmental stage and the understanding of criminal motivation is still limited. Nevertheless, in terms of the CPTED Program, one might propose not only those strategies that indirectly affect the offender through the environment, but also those that redirect human energy from illegal or destructive activity to legal or constructive outlets (including activity support strategies).
Territorial concern, social cohesion, and a general sense of security can be reinforced through the development of the identity and image of a community. Recognized consciously, this approach can improve not only the image the population has of itself, and its domain, but also the projection of that image to others. With a definition and raising of standards and expectations, patterns of social estrangement decline, together with opportunities for aberrant or criminal behavior. CPTED application of this approach holds implications for the interaction of people and their built environment, especially by means of their participation in the physical upgrading and in the identity and image development of their territory.
For CPTED to be successful, it must be natural for the user of the building or area to use the concepts. The user is the individual with ownership and an interest in the security of their surroundings. A CPTED design assumes that all space has some designated purpose (Does the space clearly belong to someone or some group?); has social, cultural, legal or physical definitions (Is the intended use clearly defined?) ; and is designed to support and control a specific behavior (Does the physical design provide the means for normal users to naturally control activities, control access and provide surveillance?). Five basic types of information are used for good CPTED planning: crime analysis, demographic, land use, personal observations and user input.
Clear border definition. Clearly marked transition zones from public
to private areas.
Placing gathering areas in locations with natural surveillance and access control by users.
Locate gathering areas away from view by outsiders.
Provide natural barriers between conflicting activities,
Design of space to increase natural surveillance.
Assignment of public space to user or group of users.
Segregation of customers by category (juvenile, adult, family)
Lower shelves for visibility from both inside and outside.
Parking in front of stores.
Strategic location of employee work stations.
Assignment of public space through business incentives.
Limiting access to parking lots and controlling traffic flow.
Rerouting of through traffic to increase natural surveillance (promotes slower driving and on street parking).
Increased visibility and surveillance through appropriate use of landscaping (high and low height limits).
Some benefits of using CPTED are as follows:
Can be applied to facilities ranging from complex industrial parks
Can be used to reduce crime in crime infested areas or prevent crime from gaining a foothold in new facilities.
Can be used to analyze the effectiveness and integration of other crime (and more traditional) prevention methods.
Allows and influences the user(s) to gain control over the environment and use it to make a major impact on crime.
Encourages teaming by organizations with similar crime prevention goals (law enforcement, public works, social services, etc.).
Supports the development of security guidelines and standards.
Can be a major factor in revitalizing communities, including downtown areas.
Provides justification for developmental funding.
The conscientious CPTED planner must constantly and consistently ask the questions: What are you trying to do? And How can I help you do it better and cheaper? The answers to these questions will result in the careful design and use of physical space, impact criminal decisions and behavior and improve productivity and profit.
Gary R. Cook, P.E. is a registered professional engineer in the State of California, the owner of Security Design Sciences in Ventura, CA, and the publisher of Security Design Newsletter, a free quarterly publication focusing primarily on physical security issues. Mr. Cook may be contacted by email or by phone/fax at (805) 659-1952.