How Might Improved Lighting Affect Crime?

In most people's minds, there is a simple and direct relationship between lighting and crime: better lighting will deter offenders who benefit from the cover of darkness. Improved lighting means that offenders are more likely to be seen by someone who might intervene, call the police, or recognize the offender. Even if this does not happen, some offenders who fear that it might would be deterred from crime.

However, things are rarely as simple as they first appear. Professor Ken Pease,2 a crime prevention expert, has explained how improved lighting can have a variety of different effects on crime. In particular, not only can it sometimes increase crime, but it can also affect not just nighttime crime, but daylight crime as well. You should familiarize yourself with all the possible effects he discusses, which are summarized in Box 1 and Box 2.

Two theories underlie Professor Pease's ideas about the crime prevention effects of improved street lighting.

1. Street lighting is a situational crime prevention measure that focuses on reducing opportunity and increasing risk through modification of the physical environment.
2. Street lighting strengthens informal social control and community cohesion through the promotion of social interaction and investment in neighborhood infrastructure.

Described by Welsh and Farrington (2007) in a systematic review of the crime- prevention effects of improved lighting undertaken for the Swedish National Council for Crime Prevention.

Some of the effects identified by Pease are more plausible than others, but his lists can help you in two main ways: (1) they alert you to the fact that improved lighting might not always lead just to reductions in nighttime crime, but can sometimes have other results as well and (2) they alert you to possible arguments that might be used by the supporters and opponents of improved lighting.

Will Improved Lighting Displace Crime to Nearby Areas?

Pease's hypotheses concern the different ways in which improved street lighting might affect the neighborhood where it is installed. But what about nearby neighborhoods? Might not criminals simply commit their crimes where the lighting is still poor? This phenomenon, known as spatial or geographical displacement, might seem an obvious result of improved lighting, but again, matters are not so simple, as is shown by the following.

1. Research studies show that displacement occurs much less often than most people, police included, often assume. For example, a review of 55 studies of displacement undertaken for the Dutch Ministry of Justice found that displacement occurred in only 22 instances. When it did occur, it was never complete, so that there was always a net benefit of the crime prevention measure.3
2. A recent U.S. study concluded that street offenders are much more likely to adapt their methods to the new conditions or to displace their activities to a different time of the day, rather than to offend elsewhere.4
3. Rather than displacement, many recent studies have found that there is diffusion of benefits to nearby areas. This means that the crime prevention measures have a beneficial influence beyond the places that they target, perhaps because offenders are not exactly sure where the crime prevention measures have been introduced. Obviously, this is much more likely if offenders are not local residents.

For police officers, the main implication of this research is that although improved street lighting might displace crime into nearby neighborhoods, it is just as likely to reduce crime in these neighborhoods because of a diffusion of benefits.