CPTED’s goal is to minimize crime not just by reducing criminal opportunity but by fostering positive social interaction among the users of a space. It does this through natural access control, natural surveillance, territoriality, and maintenance.

Access control ensures that people using a space have a right to be there while also marking who does not belong. Design for surveillance helps occupants easily view all areas within their space, as crime is less likely to happen when someone is watching.Territoriality taps into feelings of pride or ownership of a space, which leads people to feel more inclined to protect it. And when a building or area is properly maintained, it is less likely to attract crime, as it is obvious that someone is caring for the space.

Furthermore, by creating a space where neighbors know their neighbors—even if just by sight—it creates a sense of social cohesion that can help lower crime rates.

“If you want to build social cohesion, it’s important to recognize the limits of the human brain and its capacity to recognize people and have some sort of relationship with them,” explains Sharon Chamard, a criminologist at the UAA Justice Center. “The brain tops out at about 100 people. If a building structure has more than 100 people coming and going, it’s very difficult to exert social control over that space.”

A study in the ‘70s by architect Oscar Newman looked at two adjacent public housing projects that were similar demographically in terms of variables associated with crime. The higher crime area had large high-rises with a single point of entry. The area with less crime had shorter buildings with fewer apartments on each floor and fewer families per entrance.

“Newman determined that it was the design of the building that made the difference in crime levels,” says Chamard. “Essentially, there were too many apartments and people in the first building, to the point that no one knew who belonged and who didn’t. A person’s apartment was just one door in a long row of other doors, so they felt no sense of control of the space outside their apartment door.”

Chamard studies the spatial distribution of crime and conflict over use of public space. She has plenty of ideas for how architects and builders can create safer spaces and structures.

A building complex with multiple units, for example, should be designed in relation to the street. Rooms with the most human activity—such as the kitchen or living room—should have windows facing the street so that residents can keep an eye on what’s happening. Chamard notes that when bedrooms are in the front, windows are usually covered with curtains, so nobody is watching the street.

As an example of CPTED being ignored, Chamard points to homes in the Fairview area of Anchorage. “The predominant multi-family structures are fourplexes built in the ‘80s,” she explains. “They were built in cookie-cutter fashion, which is efficient and is done for cost reasons, and they did comply with building codes at the time.”

The design had trade-offs from a crime prevention standpoint. “The building windows face toward adjacent buildings and not to the back or front of the building,” she observes. “In some areas, you can walk down the street full of fourplexes and sixplexes, and it’s like going through a tunnel; there are no windows looking out to the front.”

While this does provide good surveillance over the sides of buildings, it is not optimal from a design perspective, as these buildings limit residents’ ability to see strangers in the neighborhood.

While increased lighting would seem like an obvious choice to deter crime, early studies surprisingly showed that it often did the opposite. “Where there is more lighting, it’s possible that people feel safer, so they leave their homes at night,” says Chamard. “This increases a person’s risk of being a victim and also leaves their home exposed to break-ins.”

She notes that lighting is context-sensitive; not only the type, color, strength, brightness, and direction of it, but where it is used. For example, “A warehouse owner can install a bunch of strong lights around the back of the warehouse and the loading dock, but these lights only help if there are people around to see something going on and take action,” Chamard explains. “If a warehouse backs onto a wooded area where no humans live, all you’re doing is making it easier for people to break in.”

Design choices can even affect maintenance during the life of the structure. Materials that require less upkeep help the property look better and less attractive to criminals. Avoiding long, blank walls, which attract graffiti, can also help to keep properties more pristine.

Hardening targets is just one way of deterring crime. Design can also subtly influence the behavior of a space’s inhabitants. Feelings of connectedness, trust, and belonging among neighbors are what Chamard refers to as social cohesion. Enhancing social cohesion through physical and social design can improve guardianship—when people recognize something unusual is going on and choose to intervene.

“Knowing who your neighbors are is important; I’ve lived in the same house for twenty years, and I recognize my neighbors, even though I don’t know their names or how to contact them,” she says. “This is the whole idea behind Neighborhood Watch—to develop that communications network.”

While Neighborhood Watch programs tend to work well in stable communities with long-term homeowners, they can be more difficult to establish in socially disorganized neighborhoods with a lot of residential turnover.

“Many neighborhoods have residential instability, where people don’t live there long enough to form relationships with other people,” Chamard explains. “These areas often have a lot of renter-occupied properties, and renters tend to be less invested in an area financially, compared to property owners.”

Mechanisms that promote social cohesion include block parties, community gardens, and banding together to help neighbors in need. Emergency preparedness programs can also help, especially in higher-crime areas.

“People may not want to be identified as doing something about crime, as it makes them a target for the criminal element,” says Chamard. “But if you’re meeting neighbors and working with them on projects related to emergency preparedness, it still achieves the goal of working with other people and getting to know them.”

While CPTED for private spaces can be a challenge, protecting public spaces is even more difficult. According to Newman’s study, one way to reduce crime is to convert public space to private space as much as possible.

For example, while the Anchorage 5th Avenue Mall feels integrated with the public space on the street, the fact that it is owned by Simon Property Group, a private entity, means that the building interior can more easily be controlled.

“People treat it as public space, wandering around it without buying anything or using it as a place to walk in winter, but it is a privately owned space, so mall owners or their representatives have the right to kick people out for undesirable behaviors,” says Chamard.

When architects design a mall, considerations include controlling who goes where: for example, to cut down on young people wandering around, stores that cater to that demographic can be placed close to the entrance. Stores that cater to an older clientele can be deeper in the mall.

“It’s all about controlling the flow of people through the mall,” says Chamard. The professor adds that groups of young people might not be committing crimes, but to other shoppers they can be disorderly or appear threatening.

Outdoor public spaces can be privatized too. When large homeless encampments were established at the former site of the Alaska Native Medical Center near downtown Anchorage, for example, the city transferred the land to developers, allowing the new owners to put up a fence and remove people for trespassing.

“It’s much like if someone pitched a tent in my backyard; I could tell them to get out and call the police,” says Chamard. “But if they pitch a tent in a park by my house, I don’t have the authority to remove them.”

In commercial areas, municipalities allow businesses with street-facing storefronts to set up cafes, displays, or vending areas on the sidewalks. In addition to being lively attractions for walk-in customers, sidewalk activity exerts more formal ownership over those areas.

“When you give business owners control over that space, they will work much harder to keep disorderly activity and crime out of it,” says Chamard.

Privatizing public space is effective, Chamard notes, but it must be balanced against the civil rights of everyone. “The problem is that then you have a public sidewalk taken over by a private entity. Is that good in the overall context of things?” asks Chamard. “From a crime prevention standpoint, it is, but it also limits the ability for others to use that public space.”

Street and traffic patterns can also relate to crime. A heavily trafficked street tends to have more crime than a less populated one, as people in busier areas aren’t as familiar with their neighbors.

“One of the safest places to live is on a cul-de-sac because residents recognize each other and their vehicles,” says Chamard. “People keep a close eye on someone who seems out of place. On a busy street, there are so many people coming and going that people who live there don’t have the capacity to know who belongs and who doesn’t.”

However, Chamard has concerns about permeability in designing walkable cities. That is, while connecting streets creates more access, that’s not a positive development from a crime prevention standpoint.

“If you look at studies on the relationship between burglary and street patterns, a strong predictor of burglary risk is how many other streets a given street connects to,” says Chamard. “A home on a street that leads to a four-way intersection has a higher burglary risk than if only one or two other roads connect to that street.”

Again, the Fairview neighborhood serves as an example. When residents felt the grid of side streets was bringing too much fast-moving traffic, the city responded by converting some four-way intersections into chicanes. The result over the last twenty years has been an improved sense of safety.

While CPTED can have a major impact on the amount of crime in an area, it’s the human element that matters most.

“You don’t necessarily need to have programs focused on crime prevention to have crime prevention,” says Chamard. “It’s bringing people together in collective activities that improve an area. That’s the ticket.”

Philosophers can debate whether a tendency toward crime is built into human nature, but whether crime occurs, and where, is certainly built into the designed environment.

“It’s hard to keep a really motivated criminal out, but if they think that they’ll be seen or that it’s too much of a pain to commit a crime in an area, they’ll find another target,” Chamard adds. “There are many other targets around, so when they perceive increased effort, they’ll typically move on.”