CPTED: Lighting The Way

This week, we are returning to our lessons in CPTED. As part of our review, CPTED is founded on four critical principles; Natural Surveillance, Natural Access Control, Territorial Reinforcement, and Maintenance. In our last post, we spoke of natural surveillance in terms of landscaping and the placement of people to increase environmental awareness and visibility. Today, we will talk about lighting and its central role in keeping us safe or placing us in peril.

When considering the implementation or improvement of current systems, we want to avoid creating glare, shadows, and light pollution. That's right, light pollution. This occurs when light is not properly directed to the surface or the area intended for illumination. Light travels in a straight line until it hits an object and reflects or is absorbed. When light fixtures fail to direct light or position fixtures improperly, we contribute to light pollution, unused or excess light.

In this photo, we can see a clear example of how light pollution exists. Undirected light will travel in a 360-degree pattern; thus, it creates and full envelope of usable light. We see this all the time in cities where the sky above is so lit up that we can no longer see the stars! Such a waste of lighting creates other issues, such as glare and shadowing. Remember, lighting aims to illuminate human activity and provide security.

Lighting sources are not created equally. Light bulb design focuses on lumens, which is the amount of light produced at the source, uniformity, or the relative luminance over and area, and a footcandle, which is the measure of light striking the surface in one square foot. To illustrate the concept of light uniformity, take a look at the photo presented here. In this picture, we can see that we create shadows from which a threat could emanate when uniformity is not achieved.

If you were parked in this lot with, say, just a few other vehicles, the possibility of someone hiding in the shadows of the vehicle and the darkness created by the lack of light uniformity is highly likely. If you are not convinced, take a look at these photos, which show a person hiding in plain sight along a walkway, yet we do not see. Can you see the student standing in plain sight?

This is the same photo with the same person; only the student stands out of the shadows in the second picture and in front of the light pole in the first picture. Again, it is incredible how the creation of shadows in our lighting efforts could put us in harm's way when the original intention was to keep us safe.

Another essential lighting issue is adaptation. When we use globe-style lighting or undirected light, it can create a glare that affects our eye's ability to adapt to lower light conditions. This adaptation makes shadows deeper and makes our eye adjustments slower. You can try this exercise at home. First, find a light source that is globed or full-round lighting. Next, try to look beyond the light. It won't be easy to see. Now, place your hand out in front of you to cover the light source and shield your eyes. You should now see what lies in the shadows and beyond.

If you didn't see the threat lying in wait, you could fall victim to a violent attack from someone hiding in plain sight. Adaptation can create some perilous situations when the original intent of the lighting was to prevent a surprise attack. However, it actually enabled it.

So how do we translate this new knowledge into actionable practice around our homes and businesses? The first consideration for your lighting choices is determining the area to be illuminated and for what purpose. Obviously, safety is the primary concern, but you can over-light a site, which is just wasteful. We need to select an appropriate fixture that directs the light to the intended area and then space the fixtures accordingly to achieve the uniformity of light coverage where shadows are not created. Remember, the other important consideration for the type of fixture is to prevent glare that may impact our eye adaption. For some fixtures, you can use shielding to help with funneling or directing the light without replacing the entire fixture. See the picture to the left.   

The final consideration is the lumen and light type; warm, cool, daylight, ect. We want to ensure proper coverage and adequate light strength without going overboard and wasting energy. In this image to the right, we can see how the light "temperature" affects the way we see in the dark. This becomes particularly important when selecting the lights for our landscaping effects. Of course, you can always consult a professional who understands these concepts well when in doubt.

I hope that this brief explanation of lighting will come in handy as you consider your choices when lighting your life. While it is not rocket science, you need to plan out your lighting in the same way you would plan out your landscaping or the design of a home. Unfortunately, this important safety consideration is often overlooked because we think all light is created equally. I hope that I have shown that it is not.

I am so fortunate to represent Boss Security Screens as their Chief Security Advisor. Their commitment to your safety demonstrates their desire to be a great resource and community partner. If you need any advice for your home or business security, don't forget to reach out to Boss Security Screens and me; we will be here if you need us.

Until next time, be safe and remain vigilant!

Written by,

Michael Johnston

Chief Security Advisor at Boss Security Screens

*The author is a paid consultant and product representative for Boss Security Screens. The information provided in this blog does not, and is not intended to, constitute legal advice; instead, all information, content, and materials are the author's opinion and for general informational purposes only. It is recommended that you consult an attorney, certified trainers, or licensed providers before acting on any information provided. This website may link to other third-party websites. Such links are for the convenience of the reader and are not endorsed by the author.

*The CPTED concepts presented in this article come from the NICP, National Institute of Crime Prevention, CPTED training manual. The definitions and verbiage contained in this article come as quoted and cited material. The purpose is to share the concepts as accurately as possible and apply them as intended.