outdoor lighting and crime, part 1 - Astronomical Society of Victoria

“Lighting has received considerable attention. Yet, evaluation designs are weak
and the results are mixed. We can have very little confidence that improved
lighting prevents crime, particularly since we do not know if offenders use lighting
to their advantage. In the absence of better theories about when and where
lighting can be effective, and rigorous evaluations of plausible lighting interventions,
we cannot make any scientific assertions regarding the effectiveness
of lighting. In short, the effectiveness of lighting is unknown.”
Eck (2002) [32] has since revised his views:
“The recent lighting studies from Great Britain appear to remove the lingering
doubts about lighting’s efficacy. Lighting appears to work in public areas, especially
residential communities. Generalizing beyond these types of settings
is highly speculative, given the rudimentary nature of current lighting theory
(Painter and Farrington, 1997 [82]). Lighting may be effective in some places,
ineffective in others and counter-productive in still other circumstances. The
problematic relationship between lighting and crime increases when one considers
that offenders need light to detect potential targets in low-risk situations
(Fleming and Burrows, 1986 [38]). As Pease (1999) [90] correctly points out,
we should address the specific conditions where lighting is effective, rather than
assume it is always effective.”
That lighting is sometimes effective against crime may be a truism. What needs to be
resolved is the extent of any net benefit in practice.
Understandably, most people want the incidence of crime to be reduced. It appears to be
widely believed by the public that more and brighter outdoor lighting would help. Of course,
extending the belief to its ultimate stage means there should be little or no crime in the bright
outdoor lighting conditions of daytime, but that is far from the facts. For example, 54 % of
violent crime in the USA occurred between 6 am and 6 pm, and only 20 % of rapes involve
unknown assailants at night (BJS 1999 [10]). Only 35 % of all burglaries in the USA are
reported to have occurred at night, or 48 % of all burglaries for which the time of occurrence
is known (UCR 1996 [111]). Note that these figures are for all reported crime in the whole
of the USA, which gives them much face validity. 3
In more recent details of crime by region in New Jersey (DLPS 2000 [29]), only the
burglary data are partitioned into night, day and unknown time. The day rate for burglary is
almost as much as the combined rate for night plus unknown time.
Graphs of percentage of violent crime as a function of time of day for years 1991 through
1996 are given in a US Juvenile Justice Bulletin (NCJRS 1999 [74]). Compared with adults,
juveniles (under 18) tend to commit a greater proportion of violent crimes in the hours
immediately after school gets out on school days. The difference is less pronounced for
robberies. The juvenile violent crime rate on non-school days tends to peak in the evening,
3 For comparison outside the USA, crime survey results indicated that nearly two-thirds of the total of
assaults, burglaries, robberies, thefts and vandalism occurred after dark in England and Wales (Ramsay and
Newton 1991 [96]). The percentage of burglaries at night was 62 %, and ten years later, another survey indicated
it was about the same (ONS 2000 [76]). In the writer’s home state of Victoria, Australia, it is understood
that most burglaries occur in daylight hours. Robberies and assaults in central Sydney, NSW, Australia showed
a peak after midnight, especially on Saturday and Sunday nights (Jochelson 1997 [54]).
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