IESNA (Illuminating Engineering Society of North America)

International Dark-Sky Association

Lighting Companies

Hubbell Lighting

Electrician Supplies

Under serious construction (just breaking ground)

At the beginning of this web site (Background) the concept of viewing a community as a collection of spaces was examined. For each space there may be two "sides," especially in a public space like a park. Usually the CPTED components are designed around the intended purpose of the space, but only during the day. In the absence of planning, unplanned activities will occur in the evening which may impact the intended users during the day (i.e. gang symbols, trash, vandalism). A well designed landscape will not only help support the appropriate activities during the day but will help discourage the inappropriate activities at night. For this discussion, a broad definition of the term landscaping is being used; one which includes lighting systems.

They only come out at night…
Over 90% of all crime occurs after dark. People are not as likely to enter a space that is poorly lit due to fear of crime. 

Lighting helps to decrease crime. Good lighting promotes a more secure environment and encourages more people to utilize a space into the evening. Lighting is considered to be one of the most important security features in parking facilities (Smith, 1996).  Lighting plays a key role in the following CPTED components:

• Natural Surveillance
  Lighting improves natural surveillance from dusk to dawn by making an entire space more visible and taking dark zones away. Motion detector lights are particularly effective since they attract natural surveillance when triggered by movement.

• Access Control
  Lighting can be used to make us feel welcomed or discouraged from using a space, possibly by influencing the intended user’s emotional state. Lighting can create a light barrier to keep bad guys away or to direct and control the attention of people to a particular area. Bollards (w/lights) add even more access control with their physical presence.

• Territoriality
  Lighting helps to display territoriality by signaling that the owner cares and may be at home. Lighting can also be used for highlighting the name or important information to the public, that was visible during the day (i.e. house protected by XYZ security or CCTV).

In summary, security lighting can help satisfy the 3 “D”s of crime prevention
Deter (discourage and prevent)
Disable (physically or psychologically)
Detect (eliminate concealment)

Other Benefits
In addition to improving crime prevention measures, proper landscape lighting provides other benefits. Like landscaping, lighting is relatively inexpensive and improves property values. Illuminating walks and patios can reveal trip hazards – this is especially important for senior citizens. Illuminating streets, parking areas, and drives can help prevent vehicular accidents.

Uniformity
 

It is important to recognize and plan for a lighting system that will produce uniformity across the area to be illuminated. This is especially important for older people. On the other hand, it’s also important to avoid blinding individuals capable of performing natural surveillance. For example, don’t place lights that might blind someone going up or down steps. To accomplish this, it may be necessary to actually have to “de-lamp” a lighting system. Other factors to consider when designing a lighting system include illuminating potential trouble spots at the appropriate height and using the appropriate intensity of light (i.e. foot candle). For example, bollards which primarily illuminate the ground would not be effective in helping to positively identify a suspect’s face.

The Illuminating Engineers Society of North America (IES) has recommended standards for lighting uniformity. The desired uniformity depends upon location (see table below) but usually ranges from 4:1 to 3:1, with 4 (or 3) being the average illuminance and 1 being the minimum illuminance.

During the design and installation process, it’s important to avoid light trespass and light pollution. Light trespass occurs when 0.5 fc, or higher, extends outside the property line. The International Dark-Sky Association has a list of practical solutions for reducing glare, saving energy, avoid light trespassing, light pollution and directing light to where it belongs (link in left panel).

Motion Detector Spotlight System
One lighting scheme for a residential property could be to install motion detector spotlights on every corner of the house. The best time to do this installation is when the home is being built (to save on costs, i.e. running of wire). Lighting system can be inexpensive to maintain since the spotlights (incandescent, so they turn on immediately) only turn on when there is motion. An added benefit of motion detector lights is that they makes “things” safe for the homeowner and guests by automatically illuminating trip hazards when someone enters the space (i.e. walking the dog or checking the barbecue).

Types of lights

Mercury Vapor
Mercury vapor is a high intensity discharge (HID) lamp that produces light from the blue/green portion of the light spectrum. Mercury vapor is often used in landscaping because of its long lamp life, ability to make vegetation appear blue/green and because its relatively inexpensive. There are a number of drawbacks to using mercury vapor in a landscape. Flowers will be reduced to a blue/green color. When seen in mercury vapor light, people is look like they’ve been dead for 3 weeks. Another drawback is that the re-strike time (turning it off and back on again generally takes between 10 – 15 minutes.  16,000 to 24,000 hours (should change in about 3.5 years)

Sodium Vapor
High Pressure
High pressure sodium vapor produces color from the yellow, orange, and red portion of the spectrum which results in the emission of a pinkish-golden light. Although the color rendition is fair to poor it does work well for senior community (walking and driving). In fact, high pressure sodium vapor is probably the most frequently used type of outdoor security lighting. There is a significant cost associated with installing a high pressure sodium vapor fixture. The re-strike time is only about 3-5 minutes.  20,000 to 28,000 hrs

Low Pressure
Low pressure sodium vapor lamps produces color from the yellow portion of the spectrum which results in the emission of an orange light. The color rendition is terrible and it is not good for the senior population. The fixture cost is high. Life 20,000 to 40,000 hrs

Metal Halide
Metal halide lamps emits a crystal white light.  They have excellent color rendition and are used extensively by used car lots. Metal halide lamps are also used for sporting events –especially when they are video taping. When they’re not taping they use high pressure sodium vapor may be used. Life 15,000 to 20,000

References

Smith, M. 1996. “Crime Prevention Through Environmental Design in Parking Facilities.” National Institute of Justice Research In Brief. NCJ157310

Sunset Books. 1984. Sunset Landscaping Illustrated. J.K. McClements & S, Fitzgerrell. Menlo Park, CA: Land Publishing Company