Understanding Landscape Lighting For The CSE:
Part 1
Landscape lighting is an important aspect of site design because a properly developed lighting plan adds beauty, safety, and security to the site. Lighting helps a site visitor find their way safely at night. Illuminated signs identify buildings and areas. Buildings and landscape features can be bathed in light to accentuate key features.
As a landscape architect in California, you must understand the fundamentals of designing a landscape lighting plan to pass the California Supplemental Exam for landscape architects.
Martin Luther King, Jr. Memorial - Yerba Buena Gardens, San Francisco © Bill Lim
Landscape Lighting Plan Goals
There can be many goals when landscape architects design exterior lighting for a site. Next time you design a lighting plan for a landscape architect project, keep these goals in mind:
- Safety
- Navigation
- Security
- Encourage the use of the space at night
Let’s examine each goal in greater detail.
Safety
The first and most important goal for any lighting design is the safety of the site’s nighttime users.
Site visitors should be able to move through a site easily and the pavement should be visible so that the user avoids tripping on hidden hazards.
Consider the color of light used for illuminating pedestrian walkways. Warm-colored light (red/yellow) disappears at lower levels than cool-colored light (blue/green). The human eye is much can see lower levels of cool-colored light than warm colored light at very low levels. For example, a bright full moon illuminates the ground with only 0.01 foot candles of cool blue-white light. Ideally, pedestrian walks will have at least 1 foot candle of illumination for safety.
Human eyes adapt slowly to rapidly changing light levels at night.
Avoid bright and dark areas in pedestrian circulation areas to improve user safety and comfort. Uniform lighting is easy on the eyes and safest for the nighttime visitor.
Navigation
Lighting is also an important part of navigation at night.
A lighting design can give emphasis and legibility of nodes for site users at night. If your site has focal points, art, or large tree, use accent lighting to illuminate these objects and gives site visitor reference points in the landscape.
Security
Lighting also improves security on a site. Humans are naturally more comfortable in well-lit areas at night. Proper illumination helps site users feel safe and identify other people. Crime is usually less prevalent when sites are consistently and uniformly lit.
While people perceive well-lit outdoor areas to be safer than dark areas, scientific studies report mixed results on crime reduction.
Lighting is just one of many variables at work in crime prevention. In fact, some studies demonstrated unlit school buildings were less likely to be vandalized than when the same buildings were illuminated with “security” lighting.
It turns out that criminals need light, as well. Even though the scientific findings on the effectiveness of lighting are mixed, site visitors prefer comfortably illuminated spaces at night.
Encourage Nighttime Use of a Site
If site users feel comfortable in the space at night, then they are more likely to use the space. Nighttime use is especially important for retail and entertainment uses where the site owner has an economic incentive to keep site users safe and comfortable.
For More Information
LSI Lighting Solutions has a free landscape lighting design guide available for download on their website. This well-illustrated guide provides a brief overview of landscape and architectural lighting techniques. Download the guide here.
The Department of Justice’s Center for Problem-oriented Policing published an interesting study about the effectiveness of street lighting on preventing crime. This guide summarizes current research on lighting’s role in crime prevention and discussed community organizing for public sector lighting improvement projects. Read the report here.
