Attachment_A_CPTED.pdf

PAGE 122 2010 Architect / Engineer Design Guide

Crime prevention through environmental design is a multi-disciplinary approach to deterring criminal behavior through environmental design. CPTED strategies rely upon the ability to influence offender decisions that precede criminal acts.

Strategies for the Built Environment

CPTED strategies rely upon the ability to influence offender decisions that precede criminal acts. Research into criminal behavior shows that the decision to offend or not to offend is more influenced by cues to the perceived risk of being caught than by cues to reward or ease of entry. Consistent with this research, CPTED based strategies emphasize enhancing the perceived risk of detection and apprehension.

The proper design and effective use of the built environment can reduce crime, reduce the fear of crime, and improve the quality of life. Built environment implementations of CPTED seek to dissuade offenders from committing crimes by manipulating the built environment in which those crimes proceed from or occur. The three most common built environment strategies are natural surveillance, natural access control and natural territorial reinforcement.

Natural surveillance and access control strategies limit the opportunity for crime. Territorial reinforcement promotes social control through a variety of measures.

Natural Surveillance

Natural surveillance increases the threat of apprehension by taking steps to increase the perception that people can be seen. Natural surveillance occurs by designing the placement of physical features, activities and people in such a way as to maximize visibility and foster positive social interaction among legitimate users of private and public space. Potential offenders feel increased scrutiny and limitations on their escape routes.

Place windows overlooking sidewalks and parking lots.

Leave window shades open.

Use passing vehicular traffic as a surveillance asset.

Create landscape designs that provide surveillance, especially in proximity to designated points of entry and opportunistic points of entry. Do not use landscape and building design that form hiding

Crime Prevention Through Environmental Design

(CPTED)

places for perpetrators of crime.

Use the shortest, least sight-limiting fence appropriate for the situation.

Use transparent weather vestibules at building entrances.

When creating lighting design, avoid poorly placed lights that create blind-spots for potential observers and miss critical areas. Ensure potential problem areas are well-lit: pathways, stairs, entrances/exits, parking areas, ATMs, phone kiosks, mailboxes, bus stops, children’s play areas, recreation areas, pools, laundry rooms, storage areas, dumpster and recycling areas, etc.

Avoid too-bright security lighting that creates blinding glare and/or deep shadows, hindering the view for potential observers. Eyes adapt to night lighting and have trouble adjusting to severe lighting disparities. Using lower intensity lights often requires more fixtures.

Use shielded or cut-off luminaires to control glare.

Place lighting along pathways and other pedestrian-use areas at proper heights for lighting the faces of the people in the space (and to identify the faces of potential attackers).

Natural surveillance measures can be complemented by mechanical and organizational measures. For example, closed-circuit television (CCTV) cameras can be added in areas where window surveillance is unavailable.

Natural Access Control

Natural access control limits the opportunity for crime by taking steps to clearly differentiate between public space and private space. By selectively placing entrances and exits, fencing, lighting and landscape to limit access or control flow, natural access control occurs.

Use a single, clearly identifiable, point of entry

Use structures to divert persons to reception areas

Incorporate maze entrances in public restrooms.

This avoids the isolation that is produced by an anteroom or double door entry system

Use low, thorny bushes beneath ground level windows.

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2010 Architect / Engineer Design Guide PAGE 123

Eliminate design features that provide access to roofs or upper levels

Use waist-level, picket-type fencing along residential property lines to control access, encourage surveillance.

Use a locking gate between front and backyards.

Use shoulder-level, open-type fencing along lateral residential property lines between side yards and extending to between back yards. They should be sufficiently unencumbered with landscaping to promote social interaction between neighbors.

Use substantial, high, closed fencing (for example, masonry) between a backyard and a public alley.

Natural access control is used to complement mechanical and operational access control measures, such as target hardening.

Natural Territorial Reinforcement

Territorial reinforcement promotes social control through increased definition of space and improved proprietary concern. An environment designed to clearly delineate private space does two things. First, it creates a sense of ownership. Owners have a vested interest and are more likely to challenge intruders or report them to the police. Second, the sense of owned space creates an environment where “strangers” or “intruders” stand out and are more easily identified.

By using buildings, fences, pavement, signs, lighting and landscape to express ownership and define public, semi-public and private space, natural territorial reinforcement occurs. Additionally, these objectives can be achieved by assignment of space to designated users in previously unassigned locations.

Maintained premises and landscaping such that it communicates an alert and active presence occupying the space.

Provide trees in residential and commercial areas.

Research results indicate that, contrary to traditional views within the law enforcement community, outdoor residential spaces with more trees are seen as significantly more attractive, more safe, and more likely to be used than similar spaces without trees.

Restrict private activities to defined private areas.

Display security system signage at access points.

Placing amenities such as seating or refreshments in common areas in a commercial or institutional setting helps to attract larger numbers of desired users.

Scheduling activities in common areas increases proper use, attracts more people and increases the perception that these areas are controlled.

Territorial reinforcement measures make the normal user feel safe and make the potential offender aware of a substantial risk of apprehension or scrutiny.

A4 SuPPLEMENTAL AND EXAMPLE MATERIAL