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Crime Prevention Through Environmental Design

“Leave your porch lights on”
“Don’t leave valuables visible in your vehicle”
“Make sure your hedges are trimmed to no higher than 3 feet”

We’ve all heard these sayings from law enforcement, over and over again. Why? Because these are tried and true crime prevention techniques and as they say, “an ounce of prevention is worth a pound of cure”. It would be easy for me to tell you these things, after 24 years in law enforcement; I’ve got them down pretty good. Instead of just telling you things like “make sure you’re exterior lights are in good working order” I want to take a minute to explain the concepts behind these little one-liners us cop like folks tend to throw out. My hope is that if you understand the principles behind these things you will be able to see your world in a different light, no pun intended. Let us start with Crime Prevention.

Crime prevention is the simple philosophy of taking action in order to prevent a crime before it happens. Seems like a pretty sensible and obvious thing right? Well, back in the day and by day I mean the early 60’s (sorry Baby Boomers), preventing crime, rather than simply reacting to it was cutting edge. Crime prevention spurred a literal tidal wave of Ivory Tower, peer reviewed, scientific studies on everything about why, when and where people commit crimes. Crime prevention brought us such things as Block Watch, problem oriented policing and crime statistics (used and perfected by the NYPD). One of the most basic and time-tested principles to come from all that science was the idea of “means, motive and opportunity”. In order for a bad guy (or girl) to actually commit a crime they need, a means, a motive and an opportunity. Take away any one of those three things and the crime can’t occur. Seems simple, right?

All truly sound crime prevention techniques incorporate this edict; means, motive and opportunity. If we apply this to our physical world one of those bad guys can’t break into your house using a large rock found on your property if you don’t have any large rocks. Nor could he climb up into your roof to gain entrance through your sky light like Spider Man if your house is designed in such a way that there is no easy way to scale it and you don’t leave ladders lying around. So, I give you, Crime Prevention Through Environmental Design.

“Crime Prevention Through Environmental Design” or CPTED (pronounced SEP-TED in cop speak) is the philosophy of applying crime prevention techniques to the physical environment that we live in. This includes our cities, our neighborhoods and our homes.

If you really want to delve into what CPTED is, you’ll find article after article of peer reviewed, scientific studies on how crime and our physical environment interact. If you really look into these things, and believe me I have (#nerdalert), you’ll find a smaller, newer subset of human psychology called “environmental psychology”. Environmental psychology is the study of how our physical environment and architecture affects us. Generally, environmental psychology is used for good, like finding ways to make people feel better, more relaxed and more focused in a given environment. Need a better example? Watch the Home and Garden TV channel, there is environmental psychology all over it! You know, the newlywed couple wanders around the multi-million dollar house “Lots of natural light, yeah...lots”

Since I’m a cop, I tend to see things at a different angle, which means I use environmental psychology for evil. Come to the dark side, we have cookies!

If we look just a little deeper into environmental psychology, we can find principles that can be applied to crime prevention. CPTED works off the presupposition that we are all, pretty much, hard wired the same way and socialized the same way. We all react the same way when we see a snake, or in my case, a spider (lots of running, screaming and allegedly, fire. ALLEGEDLY!) We all react the same way when an unexpected loud noise goes off near us. We all, for the most part, act the same way in societal settings too. Don’t believe me? Try walking into an elevator, then turn around and face everyone for the entire ride! Or the next time you attend a multi-day training class with a bunch of strangers, pick your seat. The next day, choose another seat and see how everyone reacts, hilarity ensues!

Throughout its inception, CPTED has steadily been written and rewritten as our knowledge of human psychology, sociology and even neuroscience increase. CPTED incorporates the principles of these scientific areas and applies them to things like the layout of a city park, the design of a skyscraper, the flow of a shopping mall and more importantly, your own home. In the 1990’s CPTED came up with 4 main concepts that define the philosophy; territoriality, surveillance, access control, image/maintenance. A couple other concepts were added some years later, activity support and target hardening.

Wall defines private space from public space

Let’s break it down.

Territoriality involves the definition of what is public space and what is private space. We’ve all seen the white picket fence that divides the perfectly manicured front lawn from the sidewalk. There is no question about what is public space and what is private space. People can clearly see that it’s ok for them to walk on a sidewalk but there needs to be a reason for them to cross into someone’s well-manicured yard. Territoriality also involves neighbors taking ownership of their space. As the area is used for a legitimate use (soccer games in the park, outdoor Tai Chi classes, etc.), illegitimate use tends to go down.

If you feel an ownership of your space, you keep an eye on it.

walkway defining public space from private space

Which leads us to our next concept, surveillance. If you live in a neighborhood for some time you know what it’s “baseline” is. Meaning, you know what is normal and what isn’t, you know who belongs there and who doesn’t. A good CPTED designed area will allow for natural surveillance, remember the saying “Hedges no higher than 3 feet”? That’s natural surveillance. Block Watch? An organized means of neighbors watching out for each other. When neighbors take ownership of their space and utilize surveillance they’re more apt to intervene if they see something suspicious. By intervene I mean call the police, generally.

Diagram of sight lines to neighborhood

Access control is the placement of natural and human made barriers in order to control who comes into a particular area. This can involve the use of natural items like shrubbery, trees or rock walls or human made things like doors, locks, fences and gates. There is also a delineation between psychological barriers and physical barriers. A psychological barrier might be a nicely paved path through a well-kept lawn or signage pointing to the location of the office. Anything that announces the integrity and uniqueness of an area. Physical barriers can be large planter boxes that divide the space between two areas or just a plain old six-foot wooden fence.

Broken Window Theory depicting run down alley

Onto image and maintenance. Back in 1982 a couple of really smart guys named James Wilson and George Kelling came up with a theory called the “Broken Window Theory”. We cops latched onto this right quick and in a hurry, why? Because it’s a pretty simple and self-explanatory theory and let’s face it, no one ever accused us of being smart! What is your mental image of a scary place and no, the dentist office doesn’t count? How about a dark alleyway? Or how about a neighborhood full of derelict houses with burned out shells of cars littering the street, the place looks like the zombie apocalypse rolled through? If an area looks like no one cares then people will think that, well, no one cares. The place looks like a dump so it stands to reason that no one is taking care of the place or watching the place. If no one is watching, it’s the perfect place to commit crimes! So if there’s graffiti on a fence, paint it over. Yard looks like an Amazonian jungle? Mow it! A well-maintained neighborhood gives those bad guys the feeling that the people here care about their community, they’re outside working in the yard, walking their dogs or having football parties at the neighbors.

Graph of urban decay to crime

Image maintenance, covering graffiti

Activity support is nothing more than the scheduling or designing of legitimate activity in a space. The idea behind this is that as legitimate activity increases, illegitimate activity decreases. For instance, a park with a shady reputation suddenly relocates a youth soccer league to the area. Now the park is flooded night after night with hundreds of kids, their parents, family members, coaches and park staff. The lights are kept on later; people are constantly coming and going. Would a criminal want to come here to sell drugs? Probably not. Could we find one dumb enough to try, most likely!

Target hardening is the application of both human made and natural objects to a location in order to make it more difficult to commit a crime in or around. Typical examples of this are someone replacing their front door with a heavier lock, placing something like a “Charlie bar” in a window or sliding glass door. Natural objects may be something as simple as placing a very prickly type of bush under windows making it difficult and painful to climb over. The underlying principle of target hardening really comes down to time. How much time and effort does it take for someone to break into your home, for example? If a bad guy can kick in a front door in one kick, he’s happy! If it takes him 20, he’s tired and probably getting really nervous that someone will hear or see him.

Take a minute and look at your neighborhood, your local park and especially your house through the eyes of a criminal. If you wanted to break into your house, how would you do it? Imagine that scenario and then work backwards to develop strategies to keep your family, yourself and your property safe.

So now you have the principles behind CPTED. Once you stop and really think about it, it’s pretty self-explanatory and obvious, sometimes we just need a framework to start with and then we can fill in the blanks. I hope that you’ve found the concepts to be useful and that you’ll be able to put them into play. Get out of your house, meet your neighbors, start a block watch, get involved in your community and let’s make things better.  Stay safe!