It has long been "common sense" that crime hides in darkness and that light can keep a place safer at night. Does research
back up that idea? In general, yes.
This overview frames some theoretical grounds for the effectiveness of lighting, outlines five key purposes for which lighting might be installed or upgraded, poses some key questions to help think about the potential for lighting changes in a given setting, and reviews major recent research on exterior lighting. References and resources offer greater detail, guides to common standards and strategies, and other in-depth help.
At its most basic, lighting is used to make visible that which, undetected, could result in crime. Intuitively, the general public tends to endorse increased lighting as an anticrime measure. But what kind of lighting? Where? How? The complexities arise when we try to figure out what might go undetected, whether new or improved lighting would reduce the particular crime or crimes, and what other considerations must come into play to make the project a sound idea--including how we will evaluate it.
1. Sound in Theory
Why has lighting been considered a valuable resource in crime prevention? Several of the general theories about crime developed by criminologists suggest helpful roles lighting can play.
Routine activities theory views people as increasing their risks of crime victimization because their day-to-day actions put them in riskier situations and circumstances. Educating people to avoid dark and deserted places and stay in better lighted areas would be a strategy seeking to persuade those individuals to modify their routine activities.
Situational crime prevention theory holds that particular places and situations are, for a variety of reasons, major attractors of crime and that remedying problems at these places or in particular situations will reduce crime. This theory suggests, for instance, that changes in lighting can reduce the attractiveness a specific place holds for criminal acts, whether the public in general is educated about it or not.
Social control theory suggests that we prevent crime because we exert influence (and even control) over each other formally and informally against committing criminal acts. Under this concept, lighting helps us view each other's acts and exert whatever influence we might to promote acceptable behavior and discourage criminal acts. Positive social control builds community cohesion and pride, which has been documented (Project on Human Development in Chicago Neighborhoods) to reduce crime.
These are just some examples of how general theories about crime support the role of lighting as a crime prevention measure. Any introductory criminology text provides further background on these and other theories. (See Schmallenger and Sheley as examples.)
2. From a Practical Perspective
Lighting from a practical perspective ought to play one or more of five crime prevention roles: surveillance, deterrence, detection, liability reduction, and fear reduction. Which roles and to what degrees will vary with each situation.
For example, the kinds of external lighting usually recommended for homes will focus on deterring criminals and providing surveillance opportunities by residents and neighbors. Lighting recommended for use inside the home (most frequently timers) can play a role in reducing fear.
In a retail setting, lighting provides deterrence against shoplifting and robbery, makes surveillance by those looking to the store easier, facilitates detection and identification of criminals (especially when combined with video surveillance), and reduces the store's exposure to liability claims in the event a patron becomes a crime victim. Lighting in retail parking areas often seeks to reduce customers' concerns (fears) as well as liability exposure for the business or businesses (Gordon and Brill).
At manufacturing and office sites, lighting may play a variety of roles depending on the circumstance. Parking area lighting generally seeks to address surveillance and deterrence as well as to alleviate liability. Buildings may be lighted to provide surveillance of access points and deter efforts to break in. Inside lighting may be designed to detect and identify criminals as well as to deter crime.
In public places--parks, streets, playgrounds, and the like--lighting may be used to reduce fear of these spaces, to improve surveillance by passers-by, and to increase the utility of the spaces (e.g., lighted sports courts). Public spaces (or quasi-public spaces like shopping malls) present more complex patterns of use and of possible lighting applications. Transportation areas (e.g., bus stops, subway stations) may require different lighting from typical residential streets. (Zelinka and Brennan discuss public spaces in detail.)
There are always different mixes of intentions in using lighting and always exceptions to patterns. The template above, however, reflects common purposes for working with lighting in typical community settings.
3. Making Wise Choices
Though not a full course on lighting, this paper suggests some key questions to ask as well as issues and situations to take into account when making decisions about changing lighting.
The first, though not always the simplest, question is "What are we trying to prevent?" It ought to be accompanied by the question "What are we trying to create?" If we seek to prevent theft of and from autos, improved sidewalk illumination is unlikely to help--unless pedestrians are breaking in from the sidewalk sides of the cars. If a convenience store experiences shoplifting, better parking lot lights will not be likely to help the problem.
Crime analysis and crime mapping (see "Resources and References" section) are among the new and powerful tools to identify crime patterns over both time and space. Make sure to consider seasonal changes in natural lighting and in vegetation (bare branches versus trees in full leaf, for example) and such changes as daylight saving time when examining the problem. Keep in mind that the perceptions and concerns of community members are among the things that might need to be assessed.
The second question should be "How would lighting help to reduce the crime or the risk of crime?" Many of the resources at the end of this paper can suggest the appropriate connections. For example, if lighting attracted more users to a park, that would increase the surveillance of the park, which would make it riskier for criminals to prey on the park's users. But if fights between friends are the cause of concern, is it reasonable to think that more or better lighting would stop these quarrels? Being clear about how the lighting should work will help to strengthen its design and ensure that the least intrusive lighting necessary is used. Part of answering this question is to answer a related question: "What other strategies might be used to prevent or reduce the problem?" Crime prevention through environmental design and situational crime prevention offer a host of strategies to explore (Clarke, National Crime Prevention Council).
If the tasks of the lighting are surveillance and deterrence (which are generally related), it is important to ask "Who will be there to see it?" If the area is a business office park, it is much less likely that passers-by will be present at 8:00 or 9:00 p.m. than if the area is a shopping mall. If the area is a city park, it might be argued that improved lighting will itself attract people to the area and thereby increase surveillance. Whatever the location, though, the follow-on question must be asked: "Can/will the observer report it? If reporting is unlikely, the value of lighting for surveillance needs to be reassessed. Remember, however, that surveillance needs may be intermittent. Ongoing lighting may be necessary, for example, to accommodate users of bus stops, subway stations, and parking garages, even if the users are not always present.
Some attention needs to be paid to surrounding areas and those who walk, bike, or drive past the site. The appropriate question is "Will the lighting cause glare, distraction, or disruption to those who live and work nearby and those who pass by?" On the other hand, trees that will leaf out or bushes that will block light may influence the placement of lighting and its related impacts, to name just one environmental consideration.
Given that resources are scarce, another consideration must enter the picture: "Is the installation of lighting in this situation cost effective? Are there less costly solutions?" Answering this question may require help from lighting engineers and crime analysts as well as crime prevention specialists. Answering these questions thoughtfully will not produce a specific lighting design, but it will produce the base from which a relevant, cost-effective, problem-solving design can be created.
4. Key Questions
- What are we trying to prevent? What are we trying to create?
- How would lighting work to reduce the crime or the risk of crime? What other strategies might be used to prevent or reduce the problem?
- Who will be there to see it? Can/will the observer report it?
- Will the lighting cause glare, distraction, or disruption to those who live and work nearby and those who pass by?
- Is the installation of lighting in this situation cost effective? Are there less costly solutions?
5. But Will It Work?
There have been many studies over the past 30 years or so of the effect of street lighting on crime. They vary in resources available to conduct the work, in the scope and quality of design, and in the quality of implementation.
6. A Broad and Methodical Look
Among the brightest developments in the field of lighting to prevent crime is the report published by the British Home Office on the effects of improved street lighting on crime: a systematic review gathered numerous evaluations of street lighting programs that aimed to reduce crime.
Thirteen programs met strict criteria of having street lighting as the only or the main crime prevention strategy, measuring change in a control area similar to the experimental area except for the changed lighting, having a crime measure (or crime-related measure) as an evaluation criteria, and having within the area at least 20 crimes in the period prior to the lighting change.
An analysis of all these studies taken together showed that "improved lighting led to reductions in crime." The overall reduction in crime after improved lighting was 20 percent in experimental areas compared with control areas. The authors suggest that street lighting more likely increases community pride and cohesion and resident engagement in the area and thus increases informal social control. They recommend further research to examine the impact of differences in levels of illumination, to examine crime rates using both police reports and victim surveys, and to assess public attitudes about the spaces before and after illumination.
7. Bottom line:
(Improved lighting) is an inclusive intervention benefiting the whole of neighbourhood and leads to an increase in perceived public safety. Improved street lighting is associated with greater use of public space and neighborhood streets by law-abiding citizens. Especially if well targeted to a high-crime area, improved street lighting can be a feasible, inexpensive and effective method of reducing crime.
An earlier but still relevant study, Lighting and Crime by Kenneth Pease, published by the British Institution of Lighting Engineers, examined a range of lighting studies and pointed out that carefully targeted changes in street lighting generally reduce crime, including daytime crime, which supports the idea that community energies are being engaged in a broader way than just the increase in illumination.
8. Lighting Up Could Make Reporting Go Up
A thoughtful study of alley lighting in a Chicago neighborhood found that improved lighting appeared to increase crime reporting. Daytime reports of crime in the improved area fell somewhat, but nighttime reports increased dramatically, though the area in general did not demonstrate dramatic crime increases. The Chicago Alley Lighting study suggests that lighting improvements may generate the same kind of "reporting surge" that the introduction of Neighborhood Watch (particularly its training of residents in reporting) has been documented to generate.
9. Saving Money, Stopping Crime
A study of lighting improvements in two communities--Dudley and Stoke-on-Trent, in England--showed that compared with similar but unimproved control areas, the lighting changes in these communities reduced crime by more than 40 percent (41 percent in Dudley; 43 percent in Stoke-on-Trent) compared with decreases in the control areas of 15 percent and 2 percent. Even better, the savings from reduced crime far exceeded the cost of the lighting improvements. Crime reductions saved 2.4 times the cost of the street lighting in Dudley and 10 times the cost of the lighting in Stoke-on-Trent.
10. Success as Part of a Comprehensive Approach
The National Institute of Justice documented the role of improved lighting in Solving Crime Problems in Residential Neighborhoods: Comprehensive Changes in Design, Management, and Use. This intensive study looked at four sites: Lockwood Gardens, a public housing development (Oakland, CA); Castle Square Apartments, a private rental complex (Boston, MA); Genesis Park, an urban neighborhood (Charlotte, NC); and The Village of Oak Park, a suburban neighborhood (Oak Park, IL). In each of these communities, lighting was a key element of physical changes that helped reduce and prevent crime and build community cohesion. The case studies in the report provide details of these comprehensive approaches for each location.
11. Legislating Lighting
Many communities have adopted exterior lighting standards as well as illumination standards for interior public places. Many are legislated. Some of these are in the form of building codes for new or remodeled structures; others are established as standards (e.g., the city of Redmond, Washington). Others (e.g., Oakland, California) are established as policy directives and guidance to executive branch officials with purposes and concerns spelled out but with specifics determined by executive order. Some localities (e.g., Austin, Texas) have enacted ordinances directed at reducing excessive lighting or so-called light pollution.
12. Too Much Light?
A number of people have expressed concern about excessive amounts of lighting in specific locations and excessive lighting throughout our communities. Concern has also been voiced about glare from one home to another caused by badly placed or excessive exterior lighting, about visual pollution that makes night-time driving more difficult, and about interference with astronomical and other research as a result of excessive lighting.
A number of jurisdictions have passed codes, regulations, or standards that limit what has come to be called "light pollution." Some movement has occurred toward so-called dark campuses, on the ground that vandals would not be attracted to schools that are darkened. The theory holds that vandals, graffiti writers in particular, need light in order to do their work and that any light they bring with them will stand out obviously against darkened buildings. Some schools and school districts have reported reductions in vandalism bills along with energy savings from darkening their campuses, but these studies, as reported, have not involved control areas that could provide a solid test for the premise. The International Dark Sky Association provides information on local and state laws and on a variety of program approaches at the local level to reducing unneeded lighting.
13. Next Steps
How does a community begin to shed light on its lighting? A number of key groups should be at the table. Technical experts from local utilities, building code enforcement, engineering, architectural, and planning staffs (as well as their nongovernmental counterparts) are essential. Law enforcement officers trained in crime prevention through environmental design are invaluable, as are crime mappers and crime analysts in local police departments. But transportation departments, parks and recreation, schools, senior citizen agencies, economic development agencies, highway departments, and local civic associations are also helpful resources with important information to improve the quality of decisions.