A Brief History of CPTED
Crime prevention through environmental design (CPTED) [pronounced sep-ted] is the "proper design and effective use of the built environment that can lead to a reduction in the fear and incidence of crime, and an improvement in the quality of life."1 This definition by C. Ray Jeffrey reflects the expanded, current, more holistic perspective of CPTED,2 encompassing (1) the criminal offender perspective regarding an environment and the risk of getting caught when committing a crime and (2) the social dynamics, sense of ownership of the environment, and their associated protective actions by persons who work, live, or traverse the environment en route to another destination.
This definition and the associated principles of environmental design have been established over decades of research by Wood, Jacobs, Angel, Jeffrey, Newman, Saville and Cleveland.3 The work of these professionals has resulted in the identification and definitions of concepts which have proven to reduce crime, through deterrence because prevention is not possible, where implemented and improve the quality of life for individuals who inhabit those environments.
For example, Oscar Newman's research for the U. S. Department of Housing and Urban Development in the late 1960s included a 2, 740-unit public housing high rise development, Pruitt-Igoe, which never achieved more than 60% occupancy and was torn down about 10 years after its construction at a loss of $300 million, because it had rampant crime. Across the street, an older, smaller row-house complex, Carr Square Village, occupied by an identical population, was fully occupied and free of crime during and after the construction, occupancy, and demolition of Pruitt-Igoe. Newman's research regarding multiple communities, including Pruitt-Igoe, into what caused these differences in crime resulted in a new, but related, term of "defensible space."4 This concept of ownership as a deterrent to crime has been accepted by professionals in the field and incorporated into the current widely accepted CPTED definition by Jeffrey and the associated CPTED principles.
Six concepts are cited in various references that support the design, construction, and utilization processes of an environment to effectively implement CPTED. Two of those concepts have been incorporated into the three CPTED principles noted below.
- Natural Access Control: Design features that clearly indicate public routes and discourage access to private structural elements. These features decrease an opportunity for crime by creating in an offender a perception of unacceptable risk when attempting access to private areas, which marks the stranger as a possible intruder. Such design features include placement of entrances and exits, fencing, and landscaping to control traffic flow.
- Natural Surveillance: Design features that increase the visibility of a property. These features maximize the ability of persons in the area to see persons in the vicinity and avoid trouble and allow external activities to be seen from adjacent building structures by persons who could call for help. Such design features include landscaping, lighting, window and stairway placement, and building entrance and garage layouts.
- Territorial Reinforcement: Design features that clearly indicate public and private structural elements of a property. An individual will develop a sense of territoriality for a space with frequent activities in an area, a sense of ownership. With this feeling of ownership the individual will "want" to defend his environment. This ownership does not necessarily mean legal ownership; it maybe a perceived ownership, such as the sense of ownership that employees feel for the office in which they work.5 The sense of territory and ownership by an individual is reinforced through regularly scheduled activities, inspections, and maintenance.
Earlier concepts that have been incorporated into the three major principles are:
- Maintenance:6 Characteristics of an environment that express ownership of the property. Deterioration of a property indicates less ownership involvement which can result in more vandalism, also known as the Broken Window Theory.7 If a window is broken and remains unfixed for a length of time, vandals will break more windows. Crime is more prevalent in areas that are not maintained; as a result law-abiding persons do not feel safe and do not want to frequent those areas.
- Milieu: This feature is generally associated with environmental land use and reflects adjoining land uses and the ways in which a site can be protected by specific design styles.8 For example, a diverse housing mix is more likely to have people present at all times of the day, and bedroom communities are more likely to be vacant during various times of the day. Since criminals know their neighborhoods and potential targets of crime, they are more likely to strike at times when they will not be discovered, and possibly apprehended.
Another concept that can be implemented, as required, in addition to the three other CPTED principles is
- Target Hardening:9 The use of mechanical devices (locks, security systems, alarms, and monitoring equipment) and organized crime prevention strategies (security patrols, law enforcement) make an area harder to access but may have a tendency to make the inhabitants "feel" unsafe. This technique is the opposite of "natural" which reflects crime prevention as a by-product from normal and routine use of an environment.10 Target hardening often happens after crime has been committed. The integration of similar, but customer service oriented CTPED strategies in the initial environmental design may be as effective, but less threatening.
Examples of CPTED Success
CPTED is a multi-disciplinary approach to the reduction of crime and the associated enhancement of the perception of personal safety by inhabitants of an environment. Because of their direct concern for these objectives, law enforcement agencies around the world have embraced these concepts and worked diligently within their communities and the local community resources to implement these principles in ways that are appropriate for their environments. Some cities, such as Federal Way, WA, have incorporated the CPTED design principles into their city code requirements for project design. Others utilize the concepts to guide businesses and homeowners to assess their environment and its characteristics to reduce opportunities for crime.11
- In Bridgeport, Connecticut, the Phoenix Project resulted in a 75% decline in crime, the lowest since 1972, by controlling street drug trafficking with the used of CPTED plans that included traffic control devices with one-way street design, increased tactical law enforcement, and mobilization of area businesses and residents.
- In Knoxville, Tennessee, police, traffic engineers, public works officials, and residents participated in CPTED training and its implementation to address drug trafficking and excessive vehicle traffic in residential areas. This effort required street redesign, revised park schedules, and volunteer-led security survey teams. Vehicle cut-through traffic was reduced by 90% and there is no more drive-through drug trafficking.
- In Sarasota, Florida, a successful plan to reduce crime in one neighborhood has resulted in the integration of CPTED principles into the local planning process for all development and redevelopment in that city.
- In Cincinnati, Ohio, a CPTED partnership plan with the housing authority management, residents, and police officials has resulted in a 12 to 13% decline in crime in the first three successive years after the plan was implemented.12
Participants in CPTED Implementation
There are four general groups that use the CPTED concepts, environmental designers (e.g., architects, landscape architects), land managers (e.g., park managers), community action groups (e.g., neighborhood watch groups), and law enforcement groups (e.g., park rangers, metropolitan police.) No group alone can successfully implement these principles because each has a unique perspective and knowledge base. The combination of that knowledge into a unified approach is necessary for the creation of an environment that deters crime and creates an environment where persons want to live, work, and shop in and feel "ownership" so that they will do their part to ensure its protection.13 These groups must work with the city planners, commissioners, traffic engineers, and construction managers who must review the designs and implement the planned construction-hopefully in a manner that effectively implements the desired CPTED principles.
There are definite benefits to the utilization of CPTED principles in a community for municipal leadership (ML), local law enforcement (LLE) and community residents (CR). Some of those listed in the Design Safer Communities Handbook are listed below:
- Improved perception of safety and livability in public areas and neighborhoods (ML)
- More revenue from safer and busier business districts (ML)
- Increased use of public parks and recreation facilities by residents (ML)
- Increased opportunities to develop crime prevention partnerships with residents (LLE)
- Identification of potential crime problems in the community before they become serious (LLE)
- Recognition that crime prevention is everyone's responsibility (LLE)
- Improved sense of security and quality of life through reduced fear of crime (CR)
- Increased interaction among residents and stronger neighborhood bonds (CR)
- New crime prevention and problem-solving skills (CR)
- Enhanced knowledge of city government agencies and other resource (CR)14
The implementation of CPTED principles can help support community crime prevention goals. The implementation of the principles, when considered early in the design process for a community, does not increase the costs to residents or business owners. The decision process for the review and acceptance of a project will generally not be lengthened. If CPTED principles conflict with local building and fire codes, then a trained CPTED professional should be consulted to identify suitable alternatives. In some circumstances, the community design groups have worked to modify the local codes for future projects, to incorporate the CPTED principles and further enhance the safety and use of environments in that community.
CPTED Design and Planning Process
Depending on the scale of the development there are multiple stages of review and construction that take place. The following is a generic process that reflects key considerations in site design and instruction, and examples of CPTED concerns that should be addressed during each phase.
Pre-Application Meeting: Some communities require a pre-application meeting to discuss and review the expected land use before the design process begins. Discussions on the location, siting, and design of new or remodeled facilities can reduce the costs of retrofitting a design to address the desired CPTED principles.
CPTED concerns are: Once the design has been established, changes may be limited to those required by law or policy-no matter how useful (from a CPTED viewpoint) they may be. Therefore, CPTED input before the plan is reviewed can save the owner a significant amount of money and time. Such a review is not a standard practice in municipal and corporate developments.
- Schematic Design: This level of the design presents a list of the requirements regarding the intended uses of the property. This document includes the general site organization, including the building location, parking location, site entrances and exits, and building entrances and exits.
CPTED concerns are: How will the development affect the existing neighborhood and how will the neighborhood affect the security of the development? These relationships will affect later decisions regarding access control measures, surveillance opportunities from various locations on and adjacent to the site, design details, and policies regarding use.
- Design Development: This level of design lists the size and shape of buildings, parking, and other site features. Building structural features defined at this time include plumbing, lighting, and communications systems; and door and window types and locations.
CPTED concerns are: What are the design influences with regard to opportunities for crime, particularly the location of "public" and "private" activities, automobile and pedestrian routes, and the use of landscaping to provide places of concealment or reduce surveillance opportunities. Other features that have to be considered are the placement of fences, walls, dumpsters, signs and graphics, and lighting.
Plan Submission and Plan Review
- Plan Review: Local agencies' reviews of plans are limited to those items required by ordinance or local policy. Persons in the review process will review different components of the proposal; e.g., the traffic engineer will focus on access and circulation.
CPTED concerns are: Crime prevention and security issues are left to the law enforcement representative or CPTED reviewer-a review which is generally the exception than the rule-and such comments, if there is a review, may be viewed as optional.
- Planning Commission Review and Approval: This step may be required only for large projects. If there is a review it does provide an opportunity for public input on issues of crime and safety.
- Construction documents include the construction drawings and a manual of materials and product specifications. These documents are used to solicit bids for construction services and building materials and products, and to guide the site and building construction and installation of related materials.
CPTED concerns are: This documentation is often overlooked as a source of information that is beneficial is assessing the ability of a site and its buildings to reduce crime. The specifications manual can be useful in identifying problems that could result from the use of certain materials with regard to life expectancy and required maintenance. Breaking and entering, vandalism, and graffiti increase the life costs of such materials by the cost to replace the materials or to repair the damage done to the site in a timely manner-in order to implement the CPTED maintenance principle.
Bidding and Negotiation
- During Bidding and Negotiation the contractors may request material or product substitutions to reduce cost. Contractors may not understand that the substitutions are not "equivalent" and may negatively impact the CPTED principles that should be addressed.
CPTED concerns are: The substitutions can "appear" to be beneficial to the client but significantly reduce the ability of the resulting environment to reduce crime. Examples of CPTED desirable materials are graffiti resistant materials on walls and other surfaces, the use of constant (rather than average) lighting standards for pedestrians in designated areas, and the use of landscaping materials that only grow to a certain height or can easily be maintained for ease of surveillance by persons in the area.
Observation of the construction activities throughout the construction process is vital to the success of the design to ensure that the design is true to the plan and the specified materials are used in the construction process.
CPTED concerns are: The unauthorized substitutions in materials that may be contrary to the CPTED principle to be implemented in the design.
Site Use-After Construction
The way that the property will be used when it is completed is as vital to the prevention of crime as its design, including the hours of activity and scheduling, assignment of space, property maintenance, and disciplinary code for violators.
CPTED concerns are: The implementation of CPTED principles by property owners, managers, and residents is necessary to the deterrence of crime and the sense of safety for the residents.
CPTED Guidelines for Various Environments
The Department of Community Development Services in Federal Way, WA has created a CPTED Checklist to assist the designer of a proposed project in implementing the CPTED principles that are identified in the Federal Way City Code (FWCC) Section 22-1630. The checklist states the functional area performance standards by topic area, indicating whether the standard is applicable during the Site Plan Review or during the Building Permit Review; possible strategies for implementation of that principle-including a write-in section; and provides a column for the results of the agency analysis, including whether the design conforms, requires revision, or is not applicable. The topic areas for natural surveillance include: blind corners, site and building layout for non-single family development, commercial/retail/industrial and community facilities, surface parking and parking structures, common/open space areas, entrances, fencing, landscaping, exterior lighting, mix of uses, and security bars/shutters/doors. The topic areas for access control include building identification, entrances, landscaping, landscaping location, security, and signage. The topic areas for ownership are maintenance and materials.15
The Crime Prevention Unit of the Fairfield Police Department in Fairfield, CA has created a brochure to briefly explain the CPTED principles and a short sample surveys to allow businesses to assess the status of their environment with regard to the CPTED principles. The topics covered include access control, maintenance, natural surveillance, and territorial reinforcement. This allows the reader to become familiar with the concepts, assess his surroundings, and identify areas for improvement.16
The Crime Prevention Unit of the Prince William County Police Department has created an extensive guide for implementing the CPTED principles, associated strategies, and pictures that illustrate the protection strategies being presented. The topics presented include the CPTED principles; CPTED techniques for single family homes, neighborhoods, multi-family homes (single buildings and complexes), institutions, commercial "drive-throughs", commercial storefronts, shopping malls, office buildings, industries, parking garages/structures, and parks/trails/open spaces, target hardening tips and techniques, landscaping and lighting, and watch programs.17
Sample CTPED Guidelines
The actual implementation of CPTED principles is dependent on the design of the physical space in relation to the normal and expected use the space and the predictable behavior of the bona fide users and offenders. Therefore, the implementation of some CPTED principles without consideration for the space and its use may not result in the desired results. Use the examples noted below cautiously and within the perspective of a unified, professional design. When considering the design of an area, the present and future uses need to be considered.
- Fully illuminate all doorways that open to the outside.
- The front door to the building should be at least partially visible from the street.
- Install windows on all sides of the building to provide full visibility of the property.
- Construct elevators and stairwells to be open and well-lighted, not enclosed behind solid walls.
- Provide appropriate illumination to doorways that open to the outside and sidewalks.
- Select and install appropriate landscaping that will allow unobstructed views of vulnerable doors and windows from the street and other properties. Avoid landscaping that might create blind spots.
- Use security-focused, rather than aesthetically pleasing, lighting that enables pedestrians to see clearly and to identify potential threats at night. For example, high or low pressure sodium vapor lights can provide evenly distributed lighting that reduces patches of darkness at the ground level and enables the human eye to pick up details, with reduced energy consumption.18
- Make parking areas visible from windows and doors.
- Ensure signs in the front windows of businesses and commercial storefronts do not cover the windows or block necessary views of the exterior space.
- Position restrooms in office buildings to be visible from nearby offices.
- Keep dumpsters visible and avoid creating blind spots or hiding places, or place them in secured corrals or garages.
Natural Access Control
- Use signs to direct visitors or patrons to building entrances and parking.
- In a business or institution, require visitors to pass through a "checkpoint" attended by those in authority; e.g., receptionist, guard.
- Locate check-out counters at the front of the store, clearly visible from the outside.
- Provide clearly marked transitional zones that indicate movement from public to semipublic to private spaces.
- Install paving treatments, plantings, and architectural design features, such as columned gateways, to direct visitors to the proper entrance and away from private areas.
- Design streets to discourage cut-through or high-speed traffic.
- Install walkways in locations safe for pedestrians, and keep them unobstructed.
- Keep balcony railings and patio enclosures less than 42 inches high and avoid using opaque materials.
- Block off dead-end spaces with fences or gates.
- Prevent easy access to the roof or fire escape from the ground.
- Use front stoops or porches in homes to create a transitional area between the street and the home.
- Define property lines and private areas with plantings, pavement treatments, or partially see-through fences. Make private areas distinguishable from public areas.
- Use signage to identify and define areas.
- Separate employee parking from visitor parking and shipping and receiving areas.
- Keep trees and shrubs trimmed back from windows, doors and walkways. Keep shrubs trimmed to 3 feet and prune lower branches of trees up to 7 feet to maintain clear visibility.
- Use exterior lighting at night and keep it in working order.
- Enforce deed restrictions and covenants, in addition to all county codes. Disregard of these issues make a site appear uncared for and less secure.
- Maintain signs and fencing and remove graffiti promptly.
- Maintain parking areas to high standards without potholes or trash.
- Interaction between neighbors is vital to the awareness of persons and activities in the area. Management may need to create opportunities for neighbors to get to know one another.
- If security systems are utilized, ensure all employees and other authorized persons are familiar with the security system to avoid false alarms.
- Set operating hours to coincide with those of neighboring businesses.
- Avoid shifts and situations where only one employee is present.
- Fully illuminate interior spaces.
- Business associations should work together to promote shopper and business safety and the appearance of safety.
Resources to Help in CPTED Implementation
Case Studies in Designing Safer Communities Handbook. Several of the case studies noted in the handbook are highlighted in the Examples of Success section of this chapter. The nine case studies provide a description of the problem, the process for determining a CPTED solution to the problem, associated city actions to resolve the problem, lessons learned, and a point of contact to discuss the case study activities. The diversity of examples provides the reader with a good introduction to the CPTED problem-solving process.
CPTED Surveys for Site Assessment in Designing Safer Communities Handbook. The handbook provides several surveys in the appendices to conduct assessments of the area being studied for solutions to the criminal activities in the area. These surveys guide the analysis and enable the CPTED planning team to assess the extent and types of crimes in the area under consideration in order to determine an appropriate solution. The surveys can be modified to address the area under consideration, but they serve as an example of ways to obtain the necessary information to design an appropriate solution to crime in an area or crime deterrence in a new residential development or business environment.
There is a Neighborhood Inventory that supports documentation of the number and types of crimes in the area and the percentage change over the past 5 years, the present and future land use for various types of dwellings in the neighborhood, the change number of dwelling and commercial types, the conditions of the neighborhood, and the ages of the persons residing in the neighborhood.
There is a Neighborhood Survey that can be used to document individual residents' perspectives on the quality of life in the neighborhood, level of problem for various activities in the neighborhood; e.g., crime, schools, drug trafficking, homelessness, noise, traffic, trash, abandoned buildings, graffiti, and unsupervised kids. Respondents are also asked about the type of community groups in which the respondent is active, the frequency with which neighbors get together for social events, respondent as a victim of crime, areas where the respondent does not feel safe, and general education/residence/income characteristics of the respondent. In closing the respondents are asked if they have any resources/skills that they would like to contribute to the neighborhood.
Resources in Designing Safer Communities Handbook. The Organizational Resources listing the appendix provides contact information for organizations that are active in areas related to crime including state criminal justice agencies, crime prevention associations, area colleges and universities, local law enforcement agencies, and local municipal planning commissions.
The CPTED Researchers and Other Experts listing in the appendix are involved in research, training, or technical assistance related to crime prevention through environmental design. The table in the appendix provides the contact information for the individuals noted and their areas of expertise. Please note that the information is provided for informational purposes and does not constitute an endorsement by the National Crime Prevention Council.
CPTED Basic, Advanced, and School training is provided at various times throughout the year in different locations and listings of available training are noted on the National Institute of Crime Prevention web site at www. nicp.net. The courses are geared for law enforcement officers, city planners, urban planners, city managers, city council members, architects, security consultants, and educators. The course fees and hotel room costs, as shown on the web site, are quite reasonable.
- Basic CPTED Training includes the following topics: Understanding CPTED Strategies and Concepts; Lighting and CPTED; Understanding Site Plans; Planning, Zoning, and CPTED; Report Writing; Barriers-Symbolic and Actual; Human Behavior and CPTED; Landscaping and CPTED; and Actual Site Plan Reviews.
- Advanced CPTED Training includes the following topics: The Effect of Color and Lighting on Human Behavior; Codes, Ordinances, and CPTED; Writing a CPTED Ordinance; Traffic Calming and CPTED; Schools and CPTED; Public Art and CPTED; Terrorism and CPTED; Parks and CPTED; and Community Planning Review.
- School CPTED Training includes the topics listed above but also includes interior design factors with regard to public areas, special purpose rooms, lockers, and restrooms.
Success: A Blend of Factors
The intent of CPTED is to discourage crime, while at the same time encouraging legitimate use of an environment. "The security program [for the building or area] is integrated into the environment, not just added on." Although the concept originated as a result of research to reduce crime in public housing projects, it has applicability to single family homes, neighborhoods, apartment complexes, public buildings, schools, parks, and recreation areas.19
The use of CPTED principles in the planning and design of buildings, office and shopping complexes, and neighborhoods can reduce the creation of problem areas in which the criminal element feels less risks of discovery and possible apprehension. With an atmosphere of safety, persons are more likely to frequent businesses and shops. With repeated presence in an area, an individual's sense of territorial ownership increases-that individual is more likely to want to protect that area. With increased ownership the individual's awareness of what is happening and the desire to alert the authorities to the problem increases, and this behavior is vital to the prevention of crime in that area.
But an environment with CPTED design principles does not guarantee an absence of crime and vandalism. To be effective and truly implement the CPTED principles, the design (industrial) factors must be blended with the social (human) factors of the environment. This blend requires the involvement of trained and dedicated individuals--a mix of government, neighborhood, and business representatives--from its design through it use, individuals from very diverse disciplines coming together to design an environment for people to experience life without fear, and improving the quality of life for all individuals-where they live, where they work, and where they play or relax, now and in the future.
1. "Designing Safer Communities: A Crime Prevention Through Environmental Design Handbook," National Crime Prevention Council, Washington, D.C., pg. 7.
2. Greg Saville and Gerry Cleveland, "2nd Generation CPTED: An Antidote to the Social Y2K Virus of Urban Design, 13 March 2008.
3. Designing Safer Communities: A Crime Prevention Through Environmental Design Handbook", National Crime Prevention Council, Washington, DC.
4. Oscar Newman, "Creating Defensible Space,", U. S. Department of Housing and Urban Development, Office of Policy Development and Research, 1972. www.humanics-es.com/defensible-space.pdf.
5. Robert Gardner, "Crime Prevention Through Environmental Design."www.crimewise.com/library/cpted.html.
6. "CPTED Design Guidelines." www.cptedsecurity.com/cpted_design_guidelines.html.
8. Greg Saville and Gerry Cleveland, "2nd Generation CPTED: An Antidote to the Social Y2K Virus of Urban Design, 13 March 2008.
9. Robert Otterstatter, "CPTED Watch," National Crime Prevention Council, Washington, DC. www.cpted-watch-com.
10. City of Mesa Police Department, "Crime Prevention through Environmental Design," CPTED Brochure. www.cityofmesa.org/police/literature/pdf/CPTED_long.pdf.
11. "Crime Prevention Through Environmental Design (CPTED) Checklist Instructions," Bulletin #021, August 18, 2004 and Crime Prevention Through Environmental Design (CPTED) Checklist," Bulletin #022, August 18, 2004, Department of Community Development Services, Federal Way, WA.
12. "Designing Safer Communities: A Crime Prevention Through Environmental Design Handbook", National Crime Prevention Council, Washington, DC, pp 2-3.
13. "CPTED FAQ," www.thecptedpage.wsu.edu/FAQ.html.
14. "Designing Safer Communities: A Crime Prevention Through Environmental Design Handbook", National Crime Prevention Council, Washington, DC, pg 4.
15. City of Mesa Police Department, "Crime Prevention Through Environmental Design," CPTED Brochure. www.cityofmesa.org/police/literature/pdf/CPTED_long.pdf.
16. Fairfield Police Department, "Business CPTED Crime Prevention Through Environmental Design," Fairfield, CA. www.ci.fairfield.ca.us/files/BusCPTED.pdf.
17. Prince William County Police Department, "CPTED Strategies, Crime Prevention Through Environmental Design, A Guide to Safe Environments in Prince William County, Virginia," Crime Prevention Unit, Woodbridge, VA. www.pwcgov.org/doclibrary/PDF/002035.pdf.
18. James Madison University, "Crime Prevention Through Environmental Design (CPTED) Standards," Safety Plan Excerpt. www.jmu.edu/safetyplan/lighting/cptedstandards.htm.
19. Robert Gardner, "Crime Prevention Through Environmental Design." www.crimewise.com/library/cpted.html.
Mollie E. Krehnke, CISSP, CHS-II, IAM, is a senior information security consultant in Raleigh, North Carolina. She and her husband, David Krehnke, are members of the inventor team for the Workstation Lock and Alar System). She has served as an information security for 20 years in assessment and implementation of information security technologies, policy, practices, procedures, and protection mechanisms in support of organizational objectives for various federal agencies, government contractors, and private organizations.