Crime Prevention Through Environmental Design (CPTED) began as a hypothesis that the physical environment influenced human behavior, more specifically criminal behavior. As CPTED principles were incorporated into architectural designs, verified and improved, the theoretical concept of CPTED was formed.

CPTED is said to have originated by criminologist C. Ray Jeffery. Parallel to Mr. Jeffery’s work, an architect by the name of Oscar Newman concentrated on a similar but smaller scale approach, referred to as defensible space. The two men published books in 1971 and 1972 respectively titled “Crime Prevention Though Environmental Design” and “Defensible Space: – Crime Prevention through Urban Design”. Several books regarding CPTED have since been written by various authors, and elements from each have been woven into the modern concept of CPTED as we know it today.


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The principles of CPTED, like a living organism, have adapted over time to changing environments. As crime has mutated from acts of theft to acts of terrorism, the principles of CPTED have similarly adapted to minimize or prevent the impact of these activities on both property and people.

The basic premise of CPTED is built upon a combination of physical and non-physical elements. The physical elements consist of natural surveillance, natural access control and natural territorial reinforcement. The non-physical elements are the intangible elements of pride and ownership, as well as the encouragement of positive activity to displace unwanted negative activity.

Since its inception and throughout the growth of the CPTED concept, other physical elements have been adopted such as target hardening and defensive space.


Regular activities in public spaces discourage illicit use of the space

Legitimate activity and crime are like oil and water: neither likes to mix with the other. Legitimate public activities will deter most crime simply by making the criminal element obvious. Likewise, areas devoid of people tend to foster criminal activity. In creating facility design it has become much more important to create activity spaces in and around developed areas. This increase of legitimate activity quickly displaces most criminal activity.

Maintaining a clear line of unobstructed visibility creates Natural Surveillance.

Surveillance: When the theory and practice of CPTED was first introduced, there was mainly one form of surveillance – Natural Surveillance. The concept of Natural Surveillance was to design public areas in and around a facility in such a way as to maximize visible areas while minimizing occluded or hidden ones. This would foster a sense of security for legitimate occupants while making those with nefarious intent somewhat nervous. Unfortunately, the nature of Natural Surveillance eliminated the concept of intimate or personal space in these areas. As technology soared in the new millennium, camera technology became smaller, more robust, and flexible. Technological Surveillance allowed for remote display / control of cameras. Digital data storage allowed for increased size of data collection, and analytic software provided capability for alarms to recognize everything from movement to items that did not belong in the space. Camera Surveillance has allowed for more intimate public areas to return as the public has become accustomed to seeing the cameras in most public areas.

A combination of landscaping, fencing and signage create natural separation of public-private spaces.

Access Control: Much like Surveillance, the concept of Access Control was essentially Natural Access Control. Natural Access Control consisted of defining the boundaries between public and private spaces by the specific placement of entrances and exits, along with fences, landscaping, and lighting to control the flow and access of people across the border of public and private areas. Technology again has changed how we control access in and out of spaces. The advent of the RFID chip and biometric readers, coupled with the ability to rapidly access large databases, has allowed the implementation of flow control devices – such as optical turnstiles, motorized gates and electric locks – to be utilized without any action of the authorized individual other than entering the detection zone. Likewise, unauthorized individuals are recorded on camera, images of them compared to databases, and authorities automatically notified if required.

Physical separation of public spaces from private common areas can be accomplished though physical barriers such as structures and fences, as well as landscaping that discourages crossing.

Defensible Space: Defensible Space resembles Territoriality in many ways, however, the primary definition is the physical layout of a space that empowers the occupants to control and defend that space. In order for Defensible Space to achieve the desired results, the space must be intimate enough that the occupants feel a connection to that space. This is where the concept of Defensible Space and Territoriality converge. Neuman himself stated that Defensible Space was a combination of physical characteristics of a space that allowed inhabitants to become the key agents in ensuring their security. For the concept to work, however, the inhabitants must have a willingness to assume this role. Defensible Space is therefore a combination of physical and psychological components that must work together to be successful.

Common space overlooked by private space often becomes an extension of the private space in the resident’s mind. It is this extension of ownership that drives territoriality.

Territoriality: Whereas Defensible Space could be said to be two parts physical and one part psychological, Territoriality could be said to be the opposite. Territoriality is present in nearly all species as a means of survival. Territoriality consists of not only personally-owned property, but also spaces to which the individual feels a connection. Usually these connections are born out of activities but are also encouraged by the design of the space, particularly designs which create a sense of intimacy. These designs would also create a welcoming environment for those who belonged there, while making those who do not belong stand out and feel less comfortable.

Bollards used to protect both patrons and the structure can be seen in front of the new Mercedes Stadium in Atlanta, rated to stop a 15,000-pound GVW truck travelling at 50 mph.

Shielding: The original intent of CPTED was to discourage crime. In the new millennium, the very definition of crime has changed to include acts of terrorism. Acts of terrorism have also changed, and with that change so has the design of public and private space. Originally, the acts were more aligned with large-scale, improvised explosive devices, as was used in the Alfred P. Murrah Federal Building in 1995. The prescribed defense of similar attacks was to increase the distance of vehicles from structures and implore the use of blast film wherever possible. Architectural design has now begun to incorporate blast dissipating features in front of structures to reduce blast impact. Lately, terrorist acts have taken on using automotive vehicles as impact weapons. As a result, technology has stepped up to the design of vehicle stopping devices, ranging from simple, fixed bollards to hydraulically operated bollards and barriers to provide protection to physical assets and pedestrians alike.

Many once-open lobby office towers are now using access control turnstiles to enter elevator lobbies.

Target Hardening: Target Hardening is a more modern principle of CPTED where the advent of new and more sophisticated technology in conjunction with the nature of modern crime has mandated its creation. Target hardening includes enhancing security by incorporating electronic access control, surveillance, intrusion detection, perimeter detection, and even graffiti detection into the building design. Physical security enhancements such as blast zones, vehicle barriers, and traffic control are also considered when hardening a facility.

Atlantic Station in Atlanta combined a “Live, Work, Play” center with CPTED principles.

The changing face of crime does make it difficult to keep the openness of space fostered by the CPTED principles. It is far too tempting to fall into the habit of building solid intrusive barriers to solve security concerns. The cost of doing so will result in islands surrounded by an element of crime rather than a fabric of space woven together which would repel the criminal element. Implementing these principles as well as integrating modern technology into the design of private-public spaces will ultimately improve quality of life, foster a productive use of space, and reduce the public’s exposure to fear, crime and liability.

CPTED in Practice at Griffith Engineering

Griffith Engineering utilizes a collaborative approach to integrating the principles of CPTED into its designs. The approach begins at conceptual design and tracks through the design process to construction. The Security Professional works with Civil Engineering, Structural Engineering, Building Architecture, Interior Architecture, Landscape Architecture, Electrical Engineering, as well as Systems Engineering in order to facilitate coordination of these design elements.  Much of how these principles are incorporated into the finished design is predicated by a series of sessions with the client regarding space programming, operations, and security, including threat assessments. As the project progresses through the phases of Conceptual Design, Schematic Design, Design Development, and Construction Documents, the CPTED principles are coordinated, reviewed and re-evaluated amongst the various disciplines. During the Construction Administration phase of a project, the high-tech electronic surveillance, duress systems, and access control systems are taken though final adjustments to complement the landscape and architectural elements as they near completion. The end result is a finished product in which all of the elements mesh to form a seamless security program that fosters a sense of security for its inhabitants and guests.

About the Author:

Michael Lovelady, CxA, CFPS, CSPM is the Director of Low Voltage Services with Griffith Engineering, Inc. in Atlanta, Georgia. Michael has more than 30 years’ experience designing low voltage systems for buildings located across the country. His expertise includes guiding clients through risk assessments and the security master planning process, as well as designing and commissioning integrated security systems. For more information as it relates to your school’s security needs, please contact Michael at his email address  here.

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