Center for Problem-Oriented Policing

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.  

Box 1: How Improved Lighting Could REDUCE Crime (adapted from Pease 1999)

In Darkness

  1. Improved lighting deters potential offenders by increasing the risk that they will be seen or recognized when committing crimes.
  2. Police become more visible, thus leading to a decision to desist from crime.
  3. If improved lighting leads to the arrest and imprisonment of repeat offenders they can no longer commit crimes in the area.
  4. New lighting can encourage residents to spend more time on their stoops or in their front yards in the evenings and thus increase informal surveillance.
  5. Improved lighting can encourage more people to walk at night, which would increase informal surveillance.

In Daylight

  1. New lighting shows that city government and the police are determined to control crime. As a result, potential offenders might no longer see the neighborhood as affording easy pickings. In additions, citizens might be motivated to pass on information about offenders.
  2. Better lighting can increase community pride and cohesiveness, leading to a greater willingness to intervene in crime and to report it.
  3. If offenders commit crime in both light and darkness, nighttime arrests and subsequent imprisonment would reduce both daytime and nighttime crime.

Box 2: How Improved Lighting Could INCREASE Crime (adapted from Pease1999)

In Darkness

  1. Increased social activity outside the home in the evenings can increase the number of unoccupied homes available for burglary.
  2. Increased visibility of potential victims allows better assessment of their vulnerability and the value of what they carry. Offenders might more easily be able to see if parked cars contain valuable items.
  3. Increased visibility allows better judgment of the proximity of "capable guardians" who might intervene in crime.
  4. Better lighting might facilitate activities like drug dealing and prostitution.
  5. Better lit streets might attract disorderly youths from nearby areas.
  6. Improved lighting of rarely used footpaths might facilitate undesirable behavior.

In Daylight

  1. Disorderly activities focused upon a newly illuminated area can spill over into the use of that place as a daylight meeting point.

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.