Crime Prevention Through Environmental Design

Crime Prevention Through Environmental Design also known as CPTED is field of knowledge developed in response to research demonstrating that the set up of some buildings deters crime while that of others invites crime. The concept of CPTED was originally designed to help reduce crime to a property (i.e. vandalism) CPTED is now known to help prevent crime from a property such as gang activity. Proper design and effective use of the built environment can lead to a reduction in the incidence and fear of crime, and to an increase in quality of life.

CPTED focuses on three concepts that attempt to reduce these factors so important to perpetrators:

Surveillance. Create clear and unobstructed sight lines in activity areas, reducing hiding places and creating the perception of witnesses.
Access Control. Emphasize primary entry points and minimize secondary outlets.
Define Ownership. Take pride in what is yours and challenge those who do not belong.
CPTED Strategies:

Clearly define the borders of space.
Clearly mark transition zones that indicate movement from public, to semi-private, to private space.
Locate gathering areas to places of natural surveillance and access control.
Put unsafe activities in safe spots, where surveillance is high and access is limited.
Place safe activities in unsafe areas. This will increase the perception of safety in these areas and help to establish territorial behavior.
Designate the use of space to provide natural barriers to conflicting activities.
Improve the scheduling of space to allow for more effective use.
Redesign the space to increase the perception of reality of natural surveillance.
Overcome distance and isolation through improved design and communications.
Why CPTED works:

Criminals usually commit crimes in "comfortable" environments. A criminal's comfort is heightened by isolation and concealment, where few witnesses exist and the chance of being identified is minimal. Criminals form perceptions about the environment surrounding a target, not the target itself. Any crime from a simple theft to the most heinous homicide will show that criminals are most fearful of being observed during the commission of the crime. Witnesses are the first step toward identification, arrest, prosecution and punishment for many criminals.

Sometimes, simple changes to an area can mean the difference between a desirable target and one that is uninspiring for the perpetrator.

The rotation of a school secretary's desk so it faces people who enter and leave the building can improve surveillance.
Educating normal users not to prop open doors for convenience can assist in better access control.
Community gardens enhance territoriality in those who tend to them and foster ownership in areas, which might otherwise be considered no man's land.
These are all simple examples of making CPTED work to improve security. CPTED requires some non-traditional thinking to arrive at the best solutions for a particular environment.