Crime prevention through environmental design (CPTED)

Crime prevention through environmental design (CPTED) is an approach to deterring crime by influencing the spaces where crimes are committed. CPTED (pronounced SEP-TED) seeks to understand the minds of criminals and determine what makes an area attractive to possible offenders. It also considers how people using certain spaces, such as tenants or workers, feel. When people feel secure in an environment, they are motivated to take note of potential trouble and report it. The CPTED approach may be used in designing new structures and spaces, but many principles can also be applied to existing environments.

Background

CPTED ideas were used in early human settlements. Forts and castles were protected by landscaping, moats or trenches, drawbridges, pike fences, and other fortifications to control who entered. Some principles were even mandated by law. For example, the Statute of Winchester was enacted in 1285 in England to force landowners to eliminate hiding places, such as ditches, along highways. Landowners who did not could be liable for crimes committed by criminals hiding on their property.

Urban planning became a big issue in the mid-twentieth century. Jane Jacobs published The Death and Life of Great American Cities in 1961. In her book, she analyzed aspects of American cities, such as what makes some city parks safe and others sites of criminal activity. She asked why some urban areas feel like neighborhoods and discussed why this was important. She cited many middle- and low-income housing blocks as costly failures. Jacobs advocated for keeping cities' quirks and flavor, rather than building sterile, futuristic metropolises. In post–World War II (1939–1945) America, her ideas were at odds with the direction of urban planning. However, her insight encouraged many city planners to reconsider their ideas.

Architect and city planner Oscar Newman also examined spaces and crime patterns during the 1960s. In 1972, he published Defensible Space, in which he describes his theories on physical design and crime prevention. In 1996, he published a follow-up work, Creating Defensible Space, for the Department of Housing and Urban Development.

Newman was particularly interested in middle- and low-income housing and the prevalence of crime in high-rise buildings. He looked at developments and compared structures ranging from three floors to thirty or more. Newman found that the breakdown of where crimes occurred in most types of structures was similar. Crime inside apartments ranged from 12 percent to 14.15 percent, while crime on outside grounds ranged from 10 percent to 16.2 percent. Crime in interior public spaces—stairwells, lobbies, elevators, and hallways—was just 5.3 percent in three-story buildings and 16.5 percent in mid-rises of six to seven floors but 37.3 percent in high-rise buildings of thirteen to thirty floors. He concluded that public areas with many users had little ownership—the more people that shared the space, the less right the people felt they had to it. This was true of interior spaces and outdoor common areas. In a building where dozens of people share a hallway, people do not feel they have the right to say anything about its state, whether the problem is trash piling up or a broken light. In walk-up units, when two or three units share a landing or hall, people have a greater feeling of ownership. They have a stronger feeling of control over the area, and they are more likely to take steps to address problems.

Until the 1970s, the prevailing wisdom was that crime was deterred through police presence and punitive measures. Researchers and the public saw little evidence that punitive measures worked. Additionally, police could not be everywhere, and patrols were costly. Planners began to look at crime prevention from a new perspective. Rather than focus on social and psychological issues that lead to criminal activity, they looked for ways to discourage crime in the places they occur. Many of Newman's ideas about territoriality and building design parallel criminologist C. Ray Jeffery's development of CPTED. Jeffery published his book, Crime Prevention through Environmental Design, in 1971.

Overview

CPTED has four principles: natural surveillance, natural access control, territorial reinforcement, and maintenance.

Natural surveillance refers to designing a space with few advantages, such as hiding places, for perpetrators. Natural surveillance is enhanced through good lighting (such as bright lights at entrances), well-placed and trimmed trees and hedges (including low, thorny shrubs near windows that discourage people from hiding there), and careful placement of dumpsters, fences, and other objects that might provide cover for perpetrators. Surveillance equipment, such as closed-circuit television cameras and monitors, placed in public spaces makes people aware that they are being watched.

Natural access control is designed to take control of a space and keep perpetrators from gaining control. This includes outside access that uses curbing and landscaping to direct pedestrians and vehicles to visible areas. Inside, natural access control often takes a maze approach to public entrances. For example, when entering a bank lobby, a customer may have to walk around a freestanding counter or other barrier to get to the tellers. A business lobby may contain a low bench or plant box between the entrance and cashiers.

Territorial reinforcement means establishing a clear boundary between public and private spaces. This ensures that people who have a reason to be there—tenants or workers—recognize who should and should not be there, and they are more likely to take action if they see strangers. This principle can be enforced by ensuring gatekeepers, such as receptionists, can see entrances clearly and have a way to easily and surreptitiously call for help—a hidden button to notify security, for example. In many places, workplace badges may be used to clearly identify who belongs, who is visiting, and who is an intruder.

Maintenance reinforces the concept of territory. If a place is in disrepair, perpetrators and those who belong get the message that nobody cares what happens. This is often called the broken windows theory—one broken window indicates a lack of care about a place, which encourages perpetrators to break another, and the disrepair escalates.

Another element of CPTED is called target hardening. This refers to efforts to make accessing a location more difficult. Deadbolts and protective window films are examples of deterrents to perpetrators. An effective lock system will discourage individuals from attempting to gain access because spending more time trying to break in increases one's chances of being detected. Window films make smash-and-grab burglaries more difficult because the window will resist shattering. Many of these ideas may be incorporated into existing homes and businesses with minimal effort and expense.

Bibliography

Atlas, Randall I. 21st Century Security and CPTED: Designing for Critical Infrastructure. 2nd ed., CRC Press, 2013.

"A Brief History of the ICA." International Crime Prevention Through Environmental Design Association, www.cpted.net/A-brief-history. Accessed 3 Feb. 2025.

“Building Resilience: Crime Prevention Through Environmental Design.” Whole Building Design Guide, www.wbdg.org/resources/crime-prevention-environmental-design. Accessed 3 Feb. 2025.

Cozens, Paul, and Terence Love. "A Review and Current Status of Crime Prevention through Environmental Design (CPTED)." Journal of Planning Literature, vol. 30, no. 4, 6 Aug. 2015, pp. 393–412.

"Crime Prevention through Environmental Design." Greater Manchester Police Design for Security, designforsecurity.org/crime-prevention-through-environmental-design. Accessed 3 Feb. 2025.

Jeffery, C. Ray. Crime Prevention through Environmental Design. SAGE Publications, Inc., 1971.

Lee, Jae Seung, et al. "Effect of Crime Prevention through Environmental Design (CPTED) Measures on Active Living and Fear of Crime." Sustainability, vol. 8, no. 9, 31 Aug. 2016.

Mawby, Robert I. "Defensible Space." Oxford Research Encyclopedia of Criminology and Criminal Justice, 26 Apr. 2017, doi.org/10.1093/acrefore/9780190264079.013.6. Accessed 3 Feb. 2025.

Newman, Oscar. "Creating Defensible Space." US Department of Housing and Urban Development, Office of Policy Development and Research, Apr. 1996, www.huduser.gov/publications/pdf/def.pdf. Accessed 3 Feb. 2025.