Crime Prevention Through Environmental Design

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Crime Prevention Through Environmental Design (CPTED) is a set of design principles used to discourage crime and promote building security. The concept is simple: Buildings and properties can be designed to prevent damage from the force of the elements and natural disasters; they should also be designed to prevent crime.

CPTED principles are based on anticipating the thought processes of a potential offender and creating an environment that discourages follow-through. CPTED has the added advantage of creating a sense of security and well-being among employees and tenants.

When CPTED is put into practice, the resulting environment, including the building and its surroundings, will discourage or impede criminal behavior, and at the same time encourage honest citizens to keep a watchful eye.

The four main principles of CPTED are:

  • Natural surveillance
  • Natural access control
  • Territorial reinforcement
  • Maintenance

Although these principles were developed for the design and construction of new buildings, the concepts can be applied to existing businesses as well.

Natural Surveillance

Criminals do not like to be seen or recognized, so they will choose situations where they can hide and easily escape. Here are some ways to incorporate natural surveillance into a business environment.

  • Keep areas well lit. In particular, building entrances should be bright at all times and provide a clear line of sight from both inside and outside.
  • Eliminate hiding spots. Cut down hedges and remove trees, bushes, fences, dumpsters, etc. that create blind spots or hiding places.
  • Low, thorny hedges work well around windows, because they don't obstruct the view in or out, and they don't provide a comfortable place to hide.
  • Use Closed Circuit Television (CCTV) to view areas without natural sight lines. Put up monitors in public areas so that visitors know they are being watched. The last thing a criminal wants to see when they enter a building is their own face on a security camera's monitor.

The result: A potential offender should feel like they are being watched, and that the surroundings offer no easy escape routes.

Natural Access Control

Criminals like to feel that they are in control. However, this sense of control can be denied by clearly marking the approaches to buildings and properties and channeling visitors into a defined area. Here are a few tips for creating natural access control:

  • Use maze entrances in public lobbies. The goal is to cut off straight-line access to a potential target, such as a bank teller or cashier. We're not talking about barbed wire -- even tension barriers that have to be jumped or navigated around can discourage the bad guys.
  • Use curbing and landscaping to direct automobile and foot traffic into a controlled, visible area.

The result: a criminal should never feel like they have the upper hand when approaching a facility.

Territorial Reinforcement

The purpose of this principle is to create a clear distinction between public and private property. This is important for two reasons: Legitimate occupants have a sense of ownership and will notice, and even challenge, people who don't belong; intruders, on the other hand, have a harder time blending in. Here are some ways to implement territorial reinforcement and secure your property:

  • Make sure receptionists have clear sightlines to all entrances, as well as the ability to quickly and discreetly call for help. A panic button that calls a central station or signals for help via an alarm light in a separate section of the building works well.
  • Make sure security signage is clearly visible at all entrances.
  • Implement a visitor badging system, and make sure that all visitors are properly escorted.

The result: Employees gain a feeling that "this is my space," while intruders are immediately put on the defensive.


Maintenance is related to territorial reinforcement. A well-maintained area sends the message that people notice and care about what happens in an area. This, in turn, discourages vandalism and other crimes. Security practitioners refer to the "Broken Windows Theory," the idea that one broken window will entice vandals to break another. A vandalized area then becomes more inviting to higher levels of crime. A property should be well-maintained as a matter of safety as well as pride.

Target Hardening

Target hardening is another strategy often mentioned in connection with CPTED. This simply means making a building more difficult to forcibly enter.

The use of deadbolt locks is one example of target hardening. To be effective, the locks should have hardened steel bolts extending at least one inch into the door jamb. When deadbolts are installed on a wooden frame door, the screws that fasten the strikes should also penetrate at least one inch into the door frame. Medeco's Maxum Deadbolt is the standard for this type of high-security lock.

Protective window films are another example of target hardening. Buildings with plate glass windows are vulnerable to "smash and grab" burglaries. But plate glass can stop a sledgehammer when a protective film is properly installed. ShatterGARD is the premier product for this application.