What is CPTED?
Crime Prevention through Environmental Design, or CPTED (pronounced "sep-ted"), is a common-sense strategy used to deter crime and create a safer environment by influencing human behavior and inhibiting criminal activity. While none of its strategies is guaranteed to eliminate future crime, CPTED is an internationally accepted method of deterring crime, both real and perceived. CPTED is comprised of four basic principles - natural surveillance, natural access control, territorial reinforcement and maintenance.
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Natural Surveillance
Natural surveillance pertains to the way in which residents and passers-by are able to observe their surroundings. The idea behind surveillance is to be able to recognize and avoid personal safety risks, while detecting and reporting any unsafe or suspicious activity. In short, natural surveillance allows us to "see and be seen," and to increase a criminal's perception that he or she is being observed.

Several factors influence the natural surveillance within an area. They include but are not limited to lighting, landscaping, orientation of architectural features such as windows, doors parking areas and porches, and general site layout. Facilitating positive exchanges, or providing "activity support," in strategic locations can also enhance natural surveillance. For example, installing a chess table in a common area allows for those using the table to observe what is happening around them in the common area, and for those in the common area to observe those at the table. Furthermore, providing a space where people can interact in a witness rich environment enhances safety for those in it, and makes it obvious to those who have "eyes on the street" when someone is not where they should be or acting suspiciously.

Lighting is one of the least costly ways to deter crime, no matter what the use of the property. Where security is an issue, such as at ATMs, in parking lots, and areas with a higher risk of crime, the recommended average illuminance is generally higher. However, there is more to security lighting than simply how bright lights are in an area. In addition to illuminance, proper security lighting takes into account how factors such as uniformity, glare, and shadows affect the prevalence of hiding spots, facilitate the proper use of security technology on the property, and enhance the overall feeling of safety.
When considering lighting options, keep in mind that an area that is well lit but not surveyed by residents is merely a well lit area for criminals to commit their crimes and go unreported. In other words, “Lighting is merely an aid for allowing observation of an item or area. If there is no observation of an area, lighting provides little benefit for security” (Richard Arrington). In Manassas, communities that request lighting surveys are encouraged to receive training in how to observe and report suspicious activity and establishing a Neighborhood Watch.
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Landscaping plays a vital role in security. In addition to aesthetically affecting the property, landscaping elements can either increase or decrease the opportunities for natural surveillance. In some cases a well-thought out landscaping plan can directly deter a would-be criminal from committing a crime. For instance, having a large shrub up against a home near a window might be an inviting hiding spot to someone planning to break in to the residence. However, if that plant is a prickly holly plant, this otherwise convenient hiding space becomes a painful area in which to hide that would likely deter someone from there staying long.

If you or your community employs a company to address its landscaping needs, it is important to clearly communicate specific needs pertaining to security in order to make your landscaping work for - and not against - your safety.

"The Tree that Ate the House" (below) is a prime example of how landscaping can impact the natural surveillance around a home:

Before / After

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Natural Access Control
The goal of natural access control is to deny criminals access to potential crime targets and to increase the perception of risk. Examples of natural access control are locating tall trees away from upperstory windows and balconies, and installing decorative barriers such as boulders to prevent ingress or egress.
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Territorial Reinforcement
Displaying ownership sends the message to potential offenders that an area is protected through stewardship and surveillance by its legitimate users. Territoriality achieves this display of ownership by helping to reinforce the difference between private, public and semi-public spaces on your property, and facilitating activity support in appropriate spaces. Territoriality is often symbolic and can be achieved through physical attributes such as fencing, lighting, pavement designs, signage, landscaping and activity support.
In a nutshell, the Broken Windows Theory of prevention projects that if a window is broken and goes unrepaired, more windows in its vicinity will soon be broken as well and the disorder will escalate. On the other hand, a property that is well maintained sends the message to would-be criminals that the property is cared for and watched, which in turn deters criminal behavior and disorder.

Suggested Reading & Additional Resources
In 2004, the Virginia CPTED Committee in collaboration with the Virginia Crime Prevention Association created Safety by Design: Creating a Safer Environment in Virginia. While the application of CPTED concepts is site specific, these CPTED Guidelines establish general principles for implementing CPTED strategies throughout the Commonwealth.
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  • Jane Jacobs: The Death and Life of Great American Cities (1961)
  • C. Ray Jeffrey: Crime Prevention Through Environmental Design (1971)
  • Oscar Newman: Defensible Space - Crime Prevention through Urban Design (1972)
  • James Q. Wilson & George L. Kelling: "Broken Windows" (1982)
  • Diane L. Zahm & National Crime Prevention Council: "Designing Safer Communities: A Crime Prevention Through Environmental Design Handbook" (1997)
  • Tim Crowe: Crime Prevention Through Environmental Design (2000)
  • Ian Colquhoun: Design Out Crime (2004)
  • Greg Saville & Garry Cleveland: "2nd Generation CPTED: "An Antidote to the Social Y2K Virus of Urban Design (2008)
  • International CPTED Association
  • Illuminating Engineering Society of North America
Online Survey Request Form

Live in the City? You can now request your free security or lighting survey online! Please keep in mind that local building and fire/life safety codes must be considered when implementing CPTED strategies.

Contact Information
 SPO C.D. Sharp
9518 Fairview Ave
Manassas, VA 20110
Tel: 703-257-8110
Fax: 703-257-5892

Email: csharp@manassasva.gov
Community Services Home

CPTED Guidelines Safety by Design International Engineering Society of North America International CPTED Association Request a Survey Online