Using Crime Prevention Through Environmental Design in Problem Solving
Tool Guide No. 8 (2007)
by Diane Zahm
Translation(s): O uso da Prevenção Criminal Pela Conceção Ambiental na Resolução de Problemas (Portuguese) PDF
Crime prevention through environmental design (CPTED) is an approach to problem-solving that asks, what is it about this location that places people at risk, or that results in opportunities for crime? In other words, why here? Three case examples will illustrate this point:
Case #1: Custodial workers routinely find evidence of smoking, drinking and vandalism in a high school lavatory.
Why here? The lavatory is in an isolated area of the building, adjacent to a ticket booth and concession stand that are active only during athletic events. The school's open lunch policy allows students to eat anywhere on campus, while monitors are assigned only to the cafeteria.
CPTED response: A lock is installed on the lavatory door, and it remains locked unless there is an athletic event. The open lunch policy has been revised: students are still allowed to leave the cafeteria but must eat in designated areas, and a faculty member is charged with patrolling these areas during lunch periods.
Case #2: The back wall of a building in an office center is repeatedly tagged with graffiti.
Why here? The taggers have selected an area that is out of the view of passers-by: a rear corner location where two buildings come together at the end of a poorly lit service lane. Visibility is further reduced by hedges at the site's perimeter. Businesses in the office center are open from 9 AM to 5 PM during the week; however the tagged building is next to a roller skating rink where activity peaks at night and on weekends.
CPTED response: Hedges are trimmed and wall-mounted light fixtures installed along the service lane, with motion detection lighting in the problem area. The skating rink agrees to change to a "no re-admission" policy to keep skaters inside the building and away from the office property.
Case #3: ATM patrons at a bank are being robbed after dark.
Why here? The bank is situated along a commercial strip in a neighborhood with vacant properties and abandoned businesses. The ATM is in the front corner of the bank building, and the drive-through teller windows are at the side of the building, around the corner from the ATM. Robbers hide in the darkened drive-through teller area and attack unsuspecting ATM users after they complete a transaction.
CPTED response: The bank installs a fence at the corner of the building, creating a barrier between the ATM and the drive-through teller area.
In each of these case examples, asking why here? reveals that opportunities for crime and other problems arise out of a variety of environmental conditions related to the building, the site, and the location and how the place is used. Solving a problem thus requires a detailed understanding of both crime and place, and the response should consider one of the three objectives of crime prevention through environmental design: control access, provide opportunities to see and be seen, or define ownership and encourage the maintenance of territory.
This guide is a resource for understanding and using crime prevention through environmental design as a problem-solving tool. The guide explains the basic principles of CPTED and outlines a process for identifying problems, evaluating the physical environment, and identifying strategies that will remove or reduce opportunities for crime.
What is Crime Prevention Through Environmental Design?
Crime prevention through environmental design is an approach to problem-solving that considers environmental conditions and the opportunities they offer for crime or other unintended and undesirable behaviors. CPTED attempts to reduce or eliminate those opportunities by using elements of the environment to (1) control access; (2) provide opportunities to see and be seen; and (3) define ownership and encourage the maintenanceof territory.§
§ For a more detailed introduction to CPTED, see Crowe (2000), Crowe and Zahm (1994), and National Crime Prevention Council (1997).
CPTED is unusual when compared with other crime prevention or security measures because it specifically focuses on aspects of the design, while the other measures tend to be directed at target hardening, i.e., denying access to a target using locks and bars, or using sensors and cameras to detect and identify an offender, supported by security guards. CPTED is unusual also when compared to some police activities. This is because CPTED encourages prevention and considers design and place, while policing has traditionally valued an efficient and effective response to incidents, and the identification and arrest of offenders.
CPTED may be distinctly different from traditional policing, yet it is very consistent with problem-oriented policing, in four ways:§§
- It considers a broad array of problems, not just crime.
- It requires a systematic analysis of crime events and the conditions and factors that contribute to opportunities for crime.
- It results in a set of programs or strategies that are proactive and tailored to the problem and the location.
- It engages an array of citizens, government agencies, and local institutions, each of which has a role to play in defining the problem and deciding upon an appropriate solution, as well as some accountability for long-term improvements.
§§ Herman Goldstein's book, Problem-Oriented Policing (1990) offers greater detail on these and other aspects of POP.
Crime prevention through environmental design is a relatively new term, but the use of design for safety and security is not. Caves and cliff dwellings, and castles and moats are good historical examples. Requirements for street lighting grew out of a need to distinguish legitimate travelers from outlaws and thieves.
Contemporary approaches, including CPTED, emerged out of research on the relationship between crime and place, theories known variously as environmental criminology, situational prevention, rational choice theory, or routine activities theory, among others.§ Each theoretical approach focuses on the crime event and how a criminal offender understands and uses the environment to commit a crime. Like CPTED, this research asks, why here? The research reveals:
- crime is specific and situational
- the distribution of crimes is related to land use and transportation networks
- offenders are opportunistic and commit crimes in places they know well
- opportunity arises out of daily routines and activities
- places with crime are often also places without observers or guardians.
§ See also Newman (1972), Jeffery (1971, 1977), Brantingham & Brantingham (1981, 1984), Clarke (1980, 1992), Cohen & Felson (1979), and Cornish & Clarke (1986).
Crime prevention through environmental design examines crime problems and the ways in which various features of the environment afford opportunities for undesirable and unwanted behaviors. CPTED attempts to remove or reduce these opportunities by changing various aspects of the building, the site, and the location, and how that place is used.
This is exactly how NOT to do CPTED! 1. It is dreadfully ugly; 2. the walls around the portable bathroom make it impossible to observe undesirable and unwanted behaviors. Credit: Ronald Clarke
These changes are directed toward three basic objectives, each of which is described briefly below, including examples of CPTED strategies:
- Control access by creating both real and perceptual barriers to entry and movement. The environment must offer cues about who belongs in a place, when they are supposed to be there, where they are allowed to be while they are there, what they should be doing, and how long they should stay. Users/ guardians can also serve as access control if they pay attention to people and activities and report unwanted behaviors to the appropriate authorities.
- fences, tree lines, hedges, or berms define the boundaries of a site
- drives, sidewalks, paths and gardens guide movement through a site
- gates and doors limit points of entry to a site or building
- signs direct movement, provide information, define appropriate activities and schedules, and identify intended users (e.g., "Employees Only")
- consistent use of colors or materials—in buildings, pavers, light fixtures, and landscaping—create an identity
- design features may be supported by locks, and enhanced with alarm systems or guards, depending on the situation
- Take advantage of design to provide opportunities to see and be seen. This includes opportunities to see from adjacent properties or the site perimeter onto the site, and possibly to see parking areas and buildings; opportunities to see from one part of the site to another; and opportunities to see parking, walkways, and other areas of the site from various locations inside the building. These design elements need to be supported by potential observers (they actually need to look for and then report unusual behavior), and by policies and procedures, for example, related to landscape maintenance.
- lighting improves the ability to observe activity and identify individuals
- windows afford views from inside to outside and outside to inside
- building location and orientation can create or remove views
- proper selection of trees, shrubs and other plant species, combined with regular maintenance, can minimize the conflict between lighting and landscaping and ensure that views on, off and around the site are preserved over the long-term
- furniture arrangements, window treatments and other interior design elements can support observation and encourage guardianship
- design features may be supported by physical security, CCTV, or guards when circumstances require them.
This ATM is placed well, using good CPTED features and has an unobstructed view from the street and patrolling police. Credit: Randy Atlas
- Use design to define ownership and encourage maintenance of territories. As mentioned previously, the design should provide cues about who belongs in a place and what they are allowed to do. Administrative support in the form of rules and regulations about use and maintenance can be critical to the success of various design applications.
- fences, hedges, tree lines or planter boxes separate spaces
- changes in elevation, or variations in paving or flooring materials, define transitions from public to private spaces
- gardens, artwork and furniture individualize spaces and show that someone cares and is paying attention
- signs establish ownership and any limits on use
- buildings, yards, gardens, sidewalks, and other features are well maintained, clean and in working order, which is a sign of guardianship
- design features may be supported by locks, alarm systems, CCTV, guards or other security measures in some situations.
Note that while CPTED is a crime prevention program, it focuses on design, not safety, and on productive use, not security. Design features are "supported" by locks, guards and alarms. Target hardening and security measures are not the primary means for improvement. Note, too, that although CPTED is frequently considered the responsibility of police, many of the tools and techniques are things that fall outside the purview of policing. This is why CPTED is a team effort, one that officers participate in but do not necessarily control.
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Using CPTED in Problem Solving
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