Rethinking Park Lighting

By Carole A. Lindstrom, MS, LC, IESNA

Typical light poles found in parks range in height from 10 to 15 feet tall. Their placement along pathways can be as close as 50 feet apart, to as far as 200 feet apart. While unshielded luminaires like these are aesthetically appealing and even offer plenty of light, the glare they produce can impair vision and make the park an uninviting place to be in the evening.

Due to current world events, there is a great deal of attention focused on ways to improve safety and security. The lighting industry has felt this effect through an increase in demand for exterior nighttime lighting. Unfortunately, this concern for safety often results in overlit lighting installations better suited for correctional facilities.

With exterior lighting there is typically a trade-off between light level and aesthetics; as illumination increases, attractiveness often decreases. While high light levels may be acceptable for certain situations, there are also many applications, such as parks, where the lighting also needs to be sensitive to aesthetic concerns.

These pole lighting installations are typical of the lighting applications found in most parks. The light poles often include post top luminaires with either metal halide or high-pressure sodium lamps, ranging from 100 to 200 watts.

Is there any scientific correlation between light levels and the perceptions of safety and attractiveness? While there have been numerous studies conducted examining the relationship between nighttime outdoor lighting and safety, they have mainly concentrated on urban settings such as streets and parking lots. In these areas safety and visibility are the primary concerns and attractiveness is not a high priority. However, the lighting needs for park settings differ from urban settings because while safety and visibility are important concerns, attractiveness of the environment is also a critical element.

While the term ?EUR??,,????'??park?EUR??,,????'?? is used to describe majestic national forests as well as municipal gardens, for the purpose of this article a park is defined as an area of land containing features such as lawns, trees, flowerbeds and walkways. Parks can be owned by private businesses, such as hotels, for the enjoyment of their patrons, or by public entities, such as cities, for use by the general public.

After Sunset

The pathway at night, lighted with typical high wattage poles.

No one can argue that the beauty of nature is something to behold, from the vibrant color of tulips on a warm spring day to the magical sparkle of stars on a crisp winter night. Humans have always been drawn to nature and have a need to connect with the environment, which is often fulfilled by a visit to a park.

Parks are mainly used during the day, when light from the sun is available to provide sufficient illumination to perform activities and create a feeling of safety. However, the human desire to bond with nature is not restricted to daylight hours. People would like to continue enjoying parks after sunset, to stroll in quiet solitude or gaze at the star-filled sky.

Unfortunately, parks typically take on a less inviting ambiance after sunset. At night, in lieu of the sun, parks depend on electric light to provide illumination to perform activities and create a safe, attractive environment. Parks may be under utilized at night because current lighting practices are not creating an attractive setting to draw visitors or providing sufficient lighting for safety.

Currently, the typical practice employed for park lighting consists of positioning light poles along walkways. The light poles typically include post top luminaires with either metal halide or high-pressure sodium lamps, ranging from 100 to 200 watts. The typical light pole varies from 10 feet to 15 feet in height and their spacing varies from 50 feet to 200 feet apart.

In general, the style of pole lighting luminaires installed in parks does not have good performance optics or adequate lamp shielding. These luminaires appear too bright in contrast to the darker park surround and create glare that is visually uncomfortable and can actually aid criminals by hindering the vision of pedestrians. The luminaires distract the viewer and detract from the scene rather than adding visual interest. Typical pole lighting luminaires are also inefficient. They emit a portion of light upward, which wastes energy and adds ?EUR??,,????'??light pollution?EUR??,,????'?? to the environment.

Field evaluations of existing parks show that current lighting installations vary widely in terms of light level, uniformity, light pole spacing, and luminaire styles. It is interesting to note their one common feature is a lack of contribution to the attractiveness of the setting.

Landscape Lighting

The author conducted a research experiment to evaluate current park lighting practices as they relate to people?EUR??,,????'???s perception of safety and attractiveness. Three different lighting scenarios were set up along a forested path. Participants first went through an area illuminated only by landscape lighting. They then entered an area lit only with pole lighting. The last portion of the path was lit with a combination of the two. This layout of the experiment indicates the path configuration and luminaire locations. See the sidebar on page 78 for the results of this experiment.

On the other hand, landscape lighting systems are designed primarily to provide attractive settings and create visually pleasing compositions. This is accomplished primarily by selective highlighting of plants, fountains and other features. For a typical landscape lighting installation, the light for performing activities and safety is a byproduct of the aesthetic design.

Typical landscape lighting systems consist of small luminaires that are either grade or tree mounted. The luminaires often include low wattage incandescent/halogen or metal halide sources with high color rendering properties.

The Study

In an attempt to establish baseline data with regard to safety and attractiveness of exterior lighting, the author conducted a research experiment to evaluate current park lighting practices. The study was performed as a thesis requirement for a Master of Science in Lighting degree from Rensselaer Polytechnic Institute in conjunction with the Lighting Research Center.

The experiment was conducted along a pathway meandering through a forested area that simulated a park-like setting. During three separate test scenarios, subjects walked down the path illuminated by landscape lighting, pole lighting and a combination scenario using both landscape and pole lighting. For each scenario the subjects completed a questionnaire regarding perception of safety, perception of attractiveness and performance of visual tasks relevant to safety. In addition to these criteria, subjects were also asked to judge brightness, uniformity and glare.

The IDA insists that proper lighting is just as important to the reduction of light pollution as it is for security purposes. High-glare lighting (pictured here) adds light pollution to the already dim sky and presents a security issue by hindering the vision of pedestrians. A good lighting system will combine low-glare fixtures with ground lighting (landscape lighting) to satisfy both needs.

The performance criteria evaluated the subjects?EUR??,,????'??? ability to perform specific tasks under the three lighting conditions. The tasks included determining the gender of a person encountered on the path, whether the person was holding an object and to identify the object. The subjects were also asked if they noticed anyone standing off the path in the wooded surround.

The following results indicate the primary findings determined from statistical analysis of the responses recorded by the subjects:

1. The lighting scenario that used a combination of landscape lighting and pole lighting was preferred for both perception of safety and task performance relevant to safety.
   A possible reason the combination lighting was preferred with regard to safety may be due to the landscape lighting component, which increased background illuminance and thereby reduced the disability glare produced by the pole lighting luminaries. Overall, the combination lighting system increased the lighted area and illuminance uniformity while diminishing shadows.
2. Landscape lighting and pole lighting were rated equally with regard to perception of safety.
   This finding is understandable because the landscape lighting luminaires were carefully aimed and positioned to achieve light levels and uniformity on the path in accordance with safety and security recommendations published by the Illuminating Engineering Society. In addition, the landscape lighting system added more light in the wooded area surrounding the path.
   The lighting systems were also considered equally safe because they each have their own drawbacks: the pole lighting creates disability glare while the landscape lighting produces lower, non-uniform light levels.
3. Landscape lighting was the least effective scenario for performing visual tasks relevant to safety.
   This can be explained because landscape lighting produces lower, non-uniform light levels that make it difficult to discern visual details, such as identifying objects held by people encountered on the path.
4. Landscape lighting was considered the most attractive scenario.

The reason for this is thought to be because landscape lighting provides a variety in light distribution, rather than the indiscriminate light produced by pole lighting. This conclusion is based on similar findings determined from studies that address attractiveness for interior lighting environments.

Conclusions

According to the International Dark-Sky Association (IDA), typical security lighting splatters light everywhere, casts harsh shadows behind trees and buildings and produces too much glare. The IDA recommends a high-pressure sodium (like the one above) or metal halide fixture to prevent glare and promote visibility.

By producing low illuminance levels and accenting specific features, landscape lighting provides parks with a different visual appearance than during the day. Landscape lighting has the ability to enhance the beauty of the nighttime environment rather than detract from it.

The most significant finding revealed by the study was that a combination of pole lighting and landscape lighting was the preferred choice when it came to a perception of safety and performance relevant to safety. Equally important, the findings have shown that the typical park lighting practice of pole lighting rated poorly in terms of both safety and attractiveness. Notably, the study also found that landscape lighting was preferred for providing the most attractive setting. It is evident from these findings that the use of landscape lighting has a dramatic effect on improving perceptions of both safety and attractiveness.

The extent of landscape lighting installed and its proportion to pole lighting is dependent on the application and the availability of planting and features to highlight. Also to be considered is the fact that adding landscape lighting usually increases maintenance and initial cost. Therefore, recommended applications would be at establishments where appearance is an important business aspect, such as hotels, wineries and botanical gardens. For these applications, the facility?EUR??,,????'???s enhanced image could translate to more patrons and justify higher rates, which would offset costs incurred from installing landscape lighting.

While not to the same degree as private establishments, landscape lighting could also be considered for use in public parks. It can be argued that much of a city?EUR??,,????'???s success is attributable to community pride. Municipalities are typically proud of their parks and are always looking for ways to improve them and make them more available to the community. As these settings may cover large areas and include open lawns, it would be more appropriate to limit landscape lighting to select areas where features are available to highlight and where people would be more inclined to congregate, such as bandstands, lake houses and pathways near the park perimeter.

To help justify the cost and maintenance impact associated with adding landscape lighting, it should be noted that the light poles installed in a combination lighting system would include lamps of lower wattage than normal (for less energy consumption). In addition, to combat the short life of incandescent/halogen lamps typically used for landscape lighting, it is recommended that the luminaires be operated slightly under voltage, which will greatly extend lamp life and also reduce the maintenance required for relamping.

Brighter lights and higher light levels do not necessarily coincide with improved feelings of safety in non-urban settings, as this study has shown. Rather, a combination of a more attractive, low wattage lighting system and light poles with higher light levels provide a setting that significantly improves feelings of both safety and attractiveness. With this newfound knowledge, there is no reason visits to park settings must be restricted to daylight hours. The installation of a properly designed lighting system can now afford us with a greater opportunity to appreciate the wonders of nature.

Basic Findings of the Study

1. 
   
   The lighting scenario that used a combination of landscape lighting and pole lighting was preferred for both perception of safety and task performance relevant to safety.
2. 
   
   Landscape lighting and pole lighting were rated equally with regard to perception of safety.
3. 
   
   Landscape lighting was the least effective scenario for performing visual tasks relevant to safety, but it was considered the most attractive scenario.