CPTED: Crime Prevention Through Environmental Design


To prepare for the coming Winter semester, I decided to start reading ahead so that I am prepared for my first assignments. The way I learn best is through interpreting an author’s views on a subject and converting them into my own thoughts; so, I decided to continue this practice in the form of a blog post.

The first chapter in ‘Effective Physical Security’ (Fifth Edition) by Lawrence J. Fennelly, covered an in-depth analysis of Crime Prevention through Environmental Design, or CPTED.

In this post, I will cover the multi-faceted security assessment guidelines and how to utilize them in a professional environment.

CPTED, developed in 1991 by Tim Crowe, is based on a security assessment performed for a Florida school district; it has since been modernized by Lawrence Fennelly in 2013 (the author of the book). CTPED is defined as the pre-emptive approach to altering the physical environment to bring about the sought-after behavior of decreased criminal activity and fear of crime.

An environment, as explained by Fennelly, relates to people and their physical/social surroundings; however, for demonstration, it can be defined as that which has identifiable territorial and system restrictions.

CPTED is used to design physical, social, management, and law enforcement directives in the goal to positively affect human behavior as people interact with their environment; this includes the fabrication of space (psychological, social, physical), the normal and anticipated/envisioned use of the space (activity/absence of activity prearranged for the space), and the expected behavior of both valid users and offenders.

In my career, CPTED will be utilized in assessing and developing security assessments for businesses; however, CPTED can be applied to residential spaces as well. For residential spaces, there are four major categories: public, semipublic, semiprivate, and private. Below, is a quick explanation of each residential space category.

Public: regardless of its legal status, a space that is recognized by members of a residential area/neighborhood as belonging to the public as a whole. In a public space, a stranger has the same perceived right to use the area as a resident.

Semipublic: space open to all members of the public without entering a guarded/locked barrier; an example of a semipublic space would be multifamily housing.

Private: space which is intended to only be used by inhabitants of a single residential unit, their allowed guests, and service personnel with access commonly controlled by locks or other physical barriers. Visitors are always challenged.

Semiprivate: space which has its access limited for use by guests, residents, and service people on valid projects. In multifamily housing, this is usually enforced by protection officers/doormen, locks, or other types of physical barriers. In a semiprivate space, visitors are confronted as possible intruders.

Target Hardening:

Any of the above spaces can benefit from target hardening: the effort of denying access to a crime target through physical or artificial barrier methods (gates, fences, alarms, locks). The magnitude of focus on target hardening necessary to ensure security depends on the privacy of the space. Having too much or too little emphasis on target hardening can have positive and negative results. For example, enforcing needless security measures onto a semipublic space, such as a civic space containing a large fountain in front of a building, would unnecessarily constrain access, use, and enjoyment.

Natural Protection/Security:

Thanks to end-of-the-world movies, I was pretty familiar with how to secure a position from zombies and other undesired guests, but I have never have given much thought to how natural protection works. For example, maintaining the surrounding bushes and trees can limit areas with high visibility of your location while being hidden from your cameras. Natural protection is merely obtaining access control as a by-product of the standard and routine use of the environment surrounding your space.

CPTED focuses on multiple overlapping strategies for natural protection: natural access control (reducing crime chance), natural observation (surveillance), territorial reinforcement (adding to the sense of territoriality through physical design. For example, something as simple as the roof design on a building can create a higher sense of security), and proper maintenance (the responsibility of facilities managers, occupants, and owners; this permits the continued use of a space for its intended purpose, as well as promoting territorial reinforcement).

Fennelly and Crowe’s ‘Three-D Approach’ to space assessment is quite interesting how it breaks everything down into three simple categories to help one determine how to appropriate how his/her space is created and utilized, based on three dimensions of human space:

  1. “All human space has some designated purpose.
  2. “All human space has social, cultural, legal, or physical definitions that prescribe the desired and acceptable behaviors.
  3. “All human space is designed to support and control the desired behaviors” (Fennelly, 2017).

Using the Three D’s, space can be assessed by inquiring the following:


What is the specified function of this space?

What was it initially envisioned to be used for?

How well does the space adapt to its current and intended use? Any resistance?


How is the space defined?

Clear who possesses it?

Where are its borders?

Any social/cultural definitions that influence how the space is handled?

Are the legal/admin rules clearly outlined and supported in policy?

Are there signs?


How well does the physical design promote its intended function?

How well does it promote the definition of the desired/accepted behaviors?

Does it conflict with/impede the productive use of the space or the functioning of the intended human activity?

Other Facets of CPTED Assessments

Crime Analysis: Police department; attained by plotting violations on a map, creating patterns of criminal activity; these patterns can be arranged geographically or by the offense. With an in-depth crime analysis of the surrounding area of a space, you can determine the percentages of certain crimes, the time of day they occur, as well as pinpoint which areas of security you will need to focus on. Often, detailed crime analysis is an excellent means to procure funding for a security-related project.

Demographic: Nature of the population for a given city, district, or neighborhood; this information is often available through city planning departments mayor’s offices, the Census, or even public libraries. By researching the demographics of a space, you can determine the age, gender, and race of the surrounding communities, providing real-world data that can be turned into analytics. With demographic data, you can apply it to the crime analysis, thus opening up a significant view of your space, and the spaces that surround it.

Land Use: Determining what your space’s land is zoned for, as well as the surround areas, is of utmost importance; this data can be retrieved through city planning departments, zoning boards, traffic engineering, and local governments. You will want to designate and illustrate the physical allocations and uses of land, whether they be commercial, residential, or industrial. Obtaining the school district and traffic flow in your area is recommended as well.

Observations: Conducting formal/informal interviews from those who either live or work in the space, as well as quiring and first-hand experience of the area and current security measures are vital to the entire process. Without the human-element, your assessment’s data is merely 1’s and 0’s, with no real personal viewpoints. Environmental cues are also paramount to common user/offender behavior. Performing a thorough walkthrough of the space and surrounding area should be performed at multiple times during the morning, lunch, and at night, to gather data on foot and automobile traffic.

Benefits of CPTED Planning

  • Dealing with lawbreaking on various environmental scales.
  • Integration of deterrence approaches.
  • Discovering short/long-term goals.
  • Inspiration of mutual responses to issues.
  • Interdisciplinary tactic to urban difficulties.
  • Reassurance of improved police/community interactions.
  • Expansion of security standards.
  • Support in urban revitalization.
  • Procurement of development funds.
  • Institutionalization of crime prevention policies/practices.


Overall, the first chapter of ‘Effective Physical Security’ by Lawrence J. Fennelly was filled with things I didn’t know, yet was surprisingly simple (and enjoyable) to read. I am glad I am learning about physical security first to get a general understanding of each protective layer a company has to defend itself against attacks, especially before I deep dive into network policies and ethical hacking.

My favorite quote from the book so far is, in regards to physical security, “participation needs to be active and creative, not passive and reactive” (Fennelly, 2017).


Fennelly, Lawrence J. (28 Nov 2016). Butterworth-Heinemann; 5th edition. “Effective Physical Security.”

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