The effects of improved street lighting in reducing crime

The summary describes the results of a Campbell Systematic Review that assesses the available research evidence on the effects of improved street lighting on crime in public space - which settings, against which crimes, and under what conditions it is most effective.

Future research should be designed to test the main theories of the effects of improved street lighting more explicitly, and future lighting schemes should employ high quality evaluation designs with long-term follow ups.Evaluation research to measure the impact of improved street lighting on crime appears to have come to a standstill. This six-year update of the first systematic review on the subject (Farrington and Welsh, 2002a) did not find one new evaluation that measured the effect of lighting on crime. This lack of new studies does not, however, detract from the EUCPN Summaries of Systematic Reviews3existing knowledge base on the crime prevention effects of improved street lighting. Future research should be designed to test the main theories of the effects of improved street lighting (i.e., community pride versus surveillance/deterrence) more explicitly. Surveys of youth in experimental and control areas could be carried out, to investigate their offending, their opinions of the area, their street use patterns, and factors that might inhibit them from offending (e.g., informal social control by older residents, increased surveillance after dark). Household surveys of adults could also be carried out, focusing on perceptions of improvements in the community, community pride, informal social control of young people, street use, and surveillance after dark. Ideally, future research should measure crime using police records, victim surveys, and self-reports of offending. It is possible that one effect of improved street lighting may be to facilitate or encourage reporting of crimes to the police; for example, if victims get a better view of offenders. Therefore, police records may be misleading. Surveys of potential victims and potential offenders are necessary for testing key hypotheses about the effects of improved lighting. The improvement in lighting in different areas should be carefully measured, including vertical and horizontal levels of illumination. Cost-benefit analyses of the impact of improved street lighting should be carried out (only 2 of the 13 studies conducted a cost-benefit analysis). It would be useful to investigate the effects of street lighting in conjunction with other crime prevention interventions. To the extent that community pride is important, this could be enhanced by other environmental improvements. To the extent that surveillance is important, this could be enhanced by other interventions, such as CCTV cameras.