Environmental Design and its Effect on Crime Prevention

There has been a lot of discussion as to how environmental design can help prevent crime. The most accepted authority on this subject is an organization called Crime Prevention Through Environmental Design (CPTED). They have formulated a three step program that appears to be adopted in many cities and countries all over the world.

By emphasizing modifications to the physical environment, CPTED says the program complements community policies, Block Watches, and other social programs that address basic causes of criminal activity. While some of what they write is intriguing, a lot of it is simply sophisticated analyses of common sense solutions. But, let’s examine what they say. Their three elements are (1) Territoriality, (2) Surveillance and (3) Access Control.

  1. They define territoriality as a person’s desire to protect his territory, his home, his spouse, his child. Psychologically, they say that if you create a clear distinction between public and private property owners will notice, and even challenge, people who don’t belong and that intruders will have a harder time blending in. The most obvious solution is to ring your property with natural or man-made borders.  Examples would be defining your space with anything that clearly delineates private property (yards, driveways, walkways) from public space (streets, sidewalks).  Examples are trees and shrubbery, alternate paving stone color, and changes in grade.

They also mention business and community watch programs, which, while certainly useful, may not have much to do with environmental design. Or they list solutions more attributable to architectural design and/or structural engineering rather than environmental (like not using pillars in garages).

  1. Surveillance.  It’s fairly obvious that criminals don’t want to be seen, so the object is to make sure that they cannot hide anywhere.  In movies, there is always a scary scene where the criminal is hiding in a dark garage behind a car. Obviously an alternative measure is to provide security and well lit areas, but these are not environmental solutions.  However, providing outside parking rather than inside does help, as open space and low bushes will not provide hiding spaces for criminals.  Most important may be to provide unobstructed views of surrounding areas. Low thorny hedges are recommended, especially around windows as they don’t provide a comfortable place to hide.  Remove anything that creates blind spots, even if they are lovely trees and buses. Other points, discussed also in Access Control, is to design curved streets so that multiple houses have views of each other and to build low fences between houses to provide better sight lines for neighbors.

 

  1. The third measure is Access Control which is defined as properly located entrances, exits, fencing and lighting. The best measures in this category are:

 

  1.   To use curbing and landscaping to direct automobile and, especially, pedestrian traffic into a visible area.
  2.   Design streets to increase pedestrian and bicycle traffic
  3.   Minimize the number of entry and exit points on a block
  4.   Design roadways to discourage through-traffic
  5.   Low fences between houses provide better sight lines between houses
  6.   Use of curved streets making criminals (entering or escaping) visible from various houses

#c above, while it may not be an environmental solution, is a good way of crime prevention, as is done in certain gated communities. Side streets leading into the community are blocked off to vehicular traffic and vehicles can only access the area by checking in and out of a guard house. This, combined with cameras on every corner, effectively stops most home robberies, especially of large items like big screen TV’s.

One of the most effective use of environmental design can be seen in Mexico (and maybe in other countries as well) where  bougainvilia bushes are used to grow on top of spiked wrought iron (or rolled barbed wire) on perimeter walls.  Adding bougainvillia, a thorny, ornamental vine accomplishes three things.  It (1) adds height to the wall, (2) disguises the spikes or barbs and (3) adds its own barbs, all the while adding an attractive element to the property.

Another part of this discussion about what to do is also what NOT to do.  In Nice, France, there was a several story cement parking garage, dubbed The Hanging Gardens.  All sorts of flowering vines were hung from the top stories.  This, more or less, hid the fact that it was an ugly cement garage and added some flowering to an urban environment. However, it probably was not good for crime prevention, because that same beautiful interlacing of vines also obscured what was going on inside the garage.

There are many other measures that have been suggested for crime prevention, but the ones cited here are the ones that most correspond to crime prevention by environmental design.