By Greg Ortt
How lighting fits into a holistic, collaborative approach to site safety
As a 28-year veteran of the lighting industry, I’ve evaluated all kinds of applications for safety in the built space with the focus on lighting—specifically how much or how little is needed to properly light the space in question. Guidelines from the IES for providing proper illumination for individual space types seemed appropriate to me for the longest time. But about seven years ago I became aware of a concept known as Crime Prevention Through Environmental Design (CPTED) and my perspective on lighting for the exterior environment changed.
After attending beginner and advanced classes over a span of five days, I realized that the space we create influences the way we feel about the safety of our surroundings. It’s important to point out that CPTED is a multi-disciplinary approach to deter criminal behavior through the use of design principles from planning, architecture, landscape architecture, law enforcement, security personnel, engineers, code enforcement and security maintenance. Yes, lighting design remains important. But new is the need for collaboration among the aforementioned functions. That’s the essence of CPTED.
The goal of this collaboration is to reduce the opportunity for crime that may be inherent in the design of a built environment. A second goal is the design of a defined space—including physical design, social management and law enforcement directives—
that seeks to positively affect human behavior as people interact with their environment.
THE INSPIRATION FOR CPTED
C. Ray Jeffery and Jane Jacobs were instrumental in the CPTED movement. They were responsible from a planning and execution perspective, and detailed how CPTED would provide a safer environment. Jacobs wrote about the “urban-to-rural transition movement” and how it would destroy our cities. Her concept for safety was simple—if you were going to stay in the city you would need to add more eyes on the space, and by doing this we would establish “ownership” and keep the space safe. Jeffery, a criminologist by trade, thought it was extremely important to design the entire environment to reduce crime.
There are two schools of thought when it comes to combating crime. The traditional approach is isolated and features only police or a repressive response. The new partnership approach integrates action by police, business, government, institutions and residents, which leads to preventive and repressive action through CPTED planning.
Want to see CPTED in action? Watch the team that comes together for the planning of a new or existing building. Many facets of the community are involved, including police, land developers, urban planners, departments of public art, transportation and parks, neighborhood and economic development groups, housing and public health departments, code enforcement personnel, political leaders, facility maintenance groups, architects and landscape architects. Speaking of landscape architects, consider how architectural features, including stairs and ramp design, interior and exterior lighting, parking lot designs, restrooms and building circulation patterns impact the safety and security of a building.
CPTED CHARACTERISTICS
CPTED is based on four key overlapping concepts: natural surveillance; natural access control; territorial reinforcement; and maintenance.
- Natural surveillance can be achieved through the placement of physical features, activities and people in a way that maximizes visibility. Landscapes are designed to provide clear and unobstructed views of the surrounding area. This includes the 2ft/6ft rule—no plants on the ground above 2 ft and no tree canopy below 6 ft.
- Natural access control calls for guiding people through a space via a strategic design of streets, sidewalks, building entrances and landscaping. This can be achieved by highlighting the main entrance and ensuring that entrances are visible, well-lit and overlooked by windows.
- Territorial reinforcement clearly defines entryways and controls other points of access to the site. This is accomplished through the use of physical attributes that express ownership, such as fencing, paving treatments, signage and landscape, which could include hostile vegetation like holly plants or raised bushes.
- Maintenance is one of the biggest factors in CPTED that is sometimes overlooked. Practitioners need to remember that over time the landscape of the built environment must be a part of the maintenance plan designed to retain the integrity of the original plan. And consider the impact of Mother Nature. When choosing equipment for the exterior be sure it is rated correctly for the environment, for example, IP-rated or stainless steel for a salt water environment. Maintenance also includes attention to landscape attributes. Trees, shrubs, etc., require constant maintenance due to growth that can inhibit the viewing area that is being designed. This will likely add additional cost to the budget, but is required to keep the site clear of visual clutter.
THE LIGHTING PIECE
Lighting has two purposes within the CPTED model. It’s used for the illumination of human activity and for security. LEDs can aid the cause. The ability to see in an LED world versus an HPS world has significantly changed our perception of spatial recognition. LEDs are normally a higher kelvin temperature lamp source, for example 4100K, as opposed to HPS at around 2000K. This has enhanced our visual perception along with uniformity, creating an evenly illuminated space and a cleaner, brighter nighttime experience. This visibility can help an individual better observe their surroundings and respond more quickly to a potential threat.
So what’s the difference between a traditional lighting layout and a CPTED layout? Traditional layouts are typically driven by the following: What is the IES recommended lighting for the space and what is the footcandle requirement from the specifier? From there, the layout is provided.
When a CPTED layout is generated, however, the IES recommended levels and footcandle requirements are important, but many other groups are involved. A “collaboration of disciplines” is established for the project and we involve the laundry list of stakeholders noted above to meet the overarching site goals, not just the lighting goals.
Adherence—or non-adherence—to CPTED principles will manifest itself in the finished project. For example, I recall a major retailer working with the county planner on a new facility that did not involve a CPTED practitioner. When construction was finished, it was discovered that the drive behind the building was too small to get a fire truck behind the building. The CPTED approach would have assured multiple sets of eyes on this plan and would have caught this oversight.
Conversely, the proactive use of CPTED can pay dividends. A contact at the Sacramento, CA, Police Department shared an anecdote with me recently that illustrates the advantages of CPTED. A motel chain with several properties was experiencing crimes at each location. CPTED, including lighting, was conducted at each motel. Photometrics were created and approved, and new LED lighting was installed. Today, crime statistics and calls for service are down considerably at each location.
This article is adapted from a presentation delivered at the 2016 IES Street & Area Lighting Conference.