CPTED is a well known program for reducing opportunities for crime. Historically, strategies rely upon the ability to influence offender decision-making that precede criminal acts.
Most implementations of CPTED occur within the built environment and therefore become defensible space. This thinking is based upon historical work now known as 1st Generation CPTED. Research into criminal behavior suggests that the decision to offend or not is influenced by cues to the perceived risk of being caught rather than the actual reward or effort required to commit a crime. Consistent with this research, CPTED based strategies emphasise enhancing the perceived risk of detection and apprehension in and around defensible space.
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.
Further iterations of CPTED focus on social motives for crime and the issues that give rise to those crime concerns. It is based upon four principles of cohesion, connectivity, culture and capacity.
There are four primary obstacles to the adoption of CPTED.
- First is a lack of knowledge of CPTED by environmental designers, land managers, and individual community members.
- Second is resistance to change. Many individuals specifically resist the type of cooperative planning that is required to use CPTED. Beyond that, sceptics reject the research and historic precedents that support the validity of CPTED concepts.
- The third obstacle is the perception that CPTED claims to be a panacea for crime that will be used to displace other more traditional approaches rather than a small, but important, complementary tool in deterring offender behaviour.
- The fourth obstacle is that many existing built areas were not designed with CPTED in mind, and modification would be expensive, politically difficult, or require significant changes in some areas of the existing built environment.