CPTED - The Commercial Demonstration in Portland, Oregon

National Institute of Justice - 1980

A 1976 CPTED demonstration was associated with the reduction of commercial and residential burglaries.

Research

CPTED

Crime Prevention

Problem Icon Problem

COMMUNITY NEED

A number of organizations, including the Portland Mayor’s Office and the Portland Police Bureau, were concerned with finding effective solutions to burglaries and robberies along Union Avenue in Portland, OR. As a result, the Union Avenue Corridor was chosen to be the site of a demonstration project for a Crime Prevention Through Environmental Design (CPTED) project. The purpose of this study is to evaluate the effectiveness of CPTED strategies and provide information on the planning and implementation of a CPTED project.

RESPONSE

CPTED aims to lower crime and fear of crime in an area by reducing the opportunity for offenders to commit crimes and by fostering positive social interaction. CPTED attempts to achieve these goals through the modification of the physical environment: e.g., street lighting, providing activity areas, and closing streets. There are four basic dimensions of CPTED: surveillance, movement control, activity support, and motivational reinforcement.

This study examines the 1976 CPTED demonstration project in Portland, OR, at the Union Avenue Corridor (UAC). Project activities included:

  • Law enforcement conducted residential and commercial security surveys in the area and street light improvements were made, including the installation of high intensity lights.
  • Knott Street was deemed a “safe street for people” and improvements were made to curbs to slow down traffic and improve aesthetics of the street.
  • Eleven new bus shelters were installed in the UAC.
  • The Northeast Business Boosters was created. The Boosters was a business improvement organization that met monthly and supported CPTED revitalization efforts.
  • Clean Up Days and Sunday Markets were created to promote community spirit.

Solution Icon Research

PRIMARY RESEARCH QUESTION(S)

The study sought to answer two primary research questions:

  1. Was the CPTED demonstration project properly implemented and did it achieve its proximate goals (increasing movement, control, surveillance, activity support, and motivational reinforcement)?
  2. Did the demonstration project reduce crime and support the CPTED theory?

RESEARCH DESIGN

First, researchers analyzed the number, type, and quality of project activities, as well as the time and cost involved in executing them. To determine whether the demonstration project achieved the proximate goals of CPTED as well as the ultimate goal of reducing crime, researchers used qualitative and quantitative measures. They conducted interviews with UAC business owners, patrol officers, and residents to measure physical security of the UAC and quality of life. Interviews were also conducted to gather data on whether people perceived the UAC to be more socially cohesive, safer, and physically appealing. Lastly, changes in the crime rate were measured through reports maintained by the police and through victimization surveys. Police file data on crime in the UAC was collected from October 1974 through September 1977.

LIMITATIONS

The final evaluation did not include a matched control area. The control would have helped to account for alternative explanations of findings which might have been affected by extraneous variables or side effects.

Outcome Icon Outcome

RESEARCH FINDINGS

Proximate Goals Findings:

  • Movement control: a majority of businesses made security improvements that were recommended by police.
  • Surveillance: 69% of residents reported good quality of lighting in the UAC; 68% of businesses had outside lights turned on at night, and 84% had inside lights turned on at night.
  • Activity support: Researchers did not find many improvements or personalizations of the built environment. The UAC was frequented by customers due to its proximity, rather than its uniqueness or amenities.
  • Motivational reinforcement: There was increased discussion of crime prevention among business owners, but not residents. Similarly, a sense of social cohesion improved among business owners but not among residents. Both residents and business owners had high perceptions of police, with 87% of business owners and 80% of residents rating police job performance as “highly favorable” or “favorable.” However, residents still had mixed opinions when asked the likelihood that an offender would be caught by police.

Crime Reduction Findings:

  • The average monthly rate of commercial burglary decreased 48% in the twenty months after the first commercial security survey. In addition, the rate showed that as time went on, commercial burglaries continued to occur less frequently. While there was a slight overall decrease in commercial burglaries in 1976 and 1977 for all of Portland, it was not comparable to the reduction in UAC.
  • Residential burglaries also decreased 14% during the same time frame.
  • These conclusions are also supported by business owners’ and residents’ perceptions of the UAC crime rate.

MAIN IMPLICATIONS

In summary, the researchers found the CPTED demonstration project to be a success that warrants further study and implementation. The project was more successful with the business community than residents, mostly because it was able to provide more social cohesion among business owners.

CITATION

Wallis, A., & Ford, D. (Eds.). (1980). Crime Prevention Through Environmental Design: The Commercial Demonstration in Portland, Oregon; executive Summary. US Department of Justice, National Institute of Justice.