Section 3: Goals of a Master Lighting PlanAnchor: #i1002032
A master lighting plan should have five major goals:
- improved safety
- environmentally judicious use of resources
- judicious energy use
- attracting tourists, businesses, and nighttime activities
- planned maintenance.
Discussions of each of these goals follow under separate subheadings.Anchor: #i1002072
Improved safety is the primary goal of public lighting. Public lighting affects motorists, cyclists, and pedestrians. Areas requiring public lighting include roadways, sidewalks, and signs. A master lighting plan can help improve overall safety by maximizing available resources and increasing management coordination. Maximizing resources means lowering operating costs of existing and new lighting systems, allowing the installation and operation of more lighting systems that operate only when needed.Anchor: #i1002082
Environmentally Judicious Use of Resources
“Environmentally judicious use of resources” refers to the consideration of citizen concerns. This consideration should encompass safety, security, aesthetic and architectural compatibility, creature comfort, sky glow, light trespass, glare, and visual clutter. These sometimes controversial concerns don’t necessarily fall into the category of “pollution,” in the sense that merely turning off the lighting would clean up any so-called pollution. Nevertheless, they are very important issues that are increasingly recognized as problems.
Some citizens want everything lit, some want nothing lit. While everyone will not likely be satisfied, the designer’s job includes consideration of the desires of the facility owner, city officials, and citizens as expressed in public hearings, local laws and ordinances, and other sources.
All outdoor lighting creates some degree of sky glow and light trespass. Sky glow is the scattering of light by moisture and dust particles in the atmosphere resulting in the halo on the horizon common over cities at night. Light trespass is the shining of light onto the property of another. For example, the shining of a street light into someone’s bedroom window would be considered light trespass.
The evaluation of sky glow is highly subjective and fervently debated among those with a keen interest in the lighting as an art, a science, or a business interest, and those who wish to view the stars and a dark nighttime sky. The term “light pollution” was coined by those who obviously desire a reduction of nighttime lighting. Those who value the implementation of much nighttime lighting include advertisers, insurers, the safety conscious, and nighttime business operators. The consequences of implementing the opposite extremes of these views are epitomized by the area around McDonald Observatory and the area around Las Vegas, Nevada.
In the traffic engineering business, the safety of the traveling public is one of the most important factors. However, we cannot do all for safety and nothing for economy. The public cannot afford to light every street all night long.
A master lighting plan provides the opportunity for all interested parties to gain more of what they want by allowing for:
- reductions in light pollution (sky glow and light trespass) during curfew hours
- more lighting for traffic safety during hours of high use (through re-investment of energy savings into more extensive lighting systems)
- outdoor advertising before curfew hours
- increased energy savings.
Development of a master lighting plan allows all community and business desires to be investigated, respected, and implemented in balance. Of course, the plan cannot solve all arguments, but, it can be used as a tool to satisfy the purposes, desires, and needs of more people than is possible with simple on-all-night luminaire switching.
A wide variety of alternatives are available for outdoor lighting. Various environmental factors should be subjectively weighted for different situations. Some factors to consider include:
- purpose of the lighting
- source type
- degree of light cutoff
- light level
- mounting height
- ambient light levels (other lighting in the area)
- historical considerations
- area land use
- roadway classification
- pedestrian and cyclist use
- implementation of lighting curfews (see Lighting Curfews, of this chapter)
- effect on wildlife (some studies show that nighttime lighting may affect wildlife).
Review the following facility types and objectively weigh the benefits derived from lighting:
- urban freeways
- rural freeways
- central business district (CBD)
- arterial roadways
- collector roadways
- residential streets
- parklands and campgrounds.
Various guidelines of national and international lighting engineering and architectural groups may be consulted for reasonable limits and strategies to optimize lighting designs and limiting negative effects. The following table shows some of these groups.
The International Commission on Illumination (CIE)
The Illuminating Engineering Society of North America (IESNA)
The European Committee for Standardization (CEN)
Judicious Energy Use
Important factors affecting energy use include light levels, lamp type, ballast type, and electrical systems quality. Lighting curfews can also help conserve energy (see Section 4, Lighting Curfews, of this chapter for more information).Anchor: #i1002271
Attracting Tourists, Businesses, and Nighttime Activities
Public lighting intended to attract tourists, CBD businesses, and nighttime activities may include pedestrian, building façade, bridge or structure, landscape, and sign lighting. The intent is to provide a pleasing and attractive environment for nighttime activities.Anchor: #i1002281
The purpose of planned maintenance is to prioritize maintenance schedules, organize contracts, and determine acceptable levels of service. Planned maintenance establishes consistent replacement products, coordinates traffic control setups, enhances the use of electronic monitoring, takes advantage of modern inventory systems, reduces trouble-shooting of problems, reduces electrical hazards, and lowers overall costs. Larger systems are more likely to have a lighting engineer available to oversee the total process of design, installation, and maintenance, thereby allowing for replacement fixtures with suitable photometric, electrical performance, and aesthetic features. Under a master lighting plan, life cycle costs, life expectancy, and quality studies are enhanced, and the region will have more buying clout. See Section 5, Electrical and Lighting Management Systems, of this chapter for a discussion of how modern electrical and lighting management systems can help with maintenance.