ANSI/IES RP-8-18: Design Of Roadway Facility Lighting

Roadway lighting designed and maintained to ANSI/IES RP-8-18

Intended to be used as a basis for the design and installation of roadway lighting and associated systems, ANSI/IES RP-8-18: Recommended Practice For Design And Maintenance Of Roadway And Parking Facility Lighting revises and supersedes numerous Illuminating Engineering Society (IES) American National Standards.

The subject of adequate road lighting is relevant to practically everyone, as we have long existed in a 24-hour society. As such, driving at night is a necessity for many. Unfortunately, even though about 25% of travel takes place after the sun has set, throughout North America, over half of all fatal collisions happen during nighttime hours.

The benefits of illumination are as clear as the visibility that roadway lighting provides. There is consensus that roadway lighting substantially decreases nighttime automobile collision rates. Furthermore, pedestrians are made safer by lighting, and roadway illumination can correlate with numerous other benefits not associated with driving, including economic benefits, as lighting may draw more people into a commercial area, aesthetics, and even making people feel safer.

By recommending proper techniques, ANSI/IES RP-8-18 allows motorists, pedestrians, and cyclists within the right of way to benefit from the value of lighting, as, if lights aren’t installed or designed properly, their benefits may be reduced.

This is the intention of ANSI/IES RP-8-18, and it, like many other standards, is distinguishable by the changes made to it during its revision process. In general, this edition of the recommended practice for design and maintenance of roadway and parking facility lighting was written as a compilation by IES staff and the IES Roadway Lighting Committee’s Special Task Group of documents authorized by several lighting organizations and authorities. During review, the committee, while sourcing standards from around the world and applying the most applicable proven practices, revisited practices on the design, installation, and maintenance methods of roadway lighting systems to add new or revised methodologies, design concepts, and procedures.

Overall, ANSI/IES RP-8-18 is a substantial revision, specifically because it aggregates the previous editions of numerous ANSI/IES RP-8 standards. As such, it supersedes the following (please note that all standards listed below are historical standards):

As it is an agglomeration of numerous subjects that previously existed as individual standards documents, ANSI/IES RP-8-18 takes an expansive and comprehensive approach towards making roadway lighting suitable to assure public safety. In many respects, the information it thoroughly details helps users achieve an understanding of various ancillary implications of roadway lighting, as it outlines as an assortment of relevant facts and issues.

Cars racing down highway with many lights

For example, Chapter 1 of ANSI/IES RP-8-18, which serves as an introduction to roadway lighting, discusses matters like alternatives to lighting, energy conservation, the need for good design, and environmental factors. Similarly, Chapter 2 addresses vision and fundamental concepts, thereby outlining the visible spectrum, the basic principles of vision, the structure of the eye, and various related topics.

These topics are in no way superfluous, as it is often necessary for users of ANSI/IES RP-8-18 to comprehend various implications associated with roadway lighting. For example, knowing how lighting can impact animal communities and influence plants’ abilities to respond to light quantity, spectrum, directionality, timing, and duration by affecting their photoreceptors could aid in the decision making of roadway lighting design and installation.

However, ANSI/IES RP-8-18 covers much more than this background information. In all, the standard exists to improve motorist visual quality, provide quality light and increased contrast for seeing hazards, illuminate conflict areas, minimize environmental impacts of light at night, and employ lighting systems that are easily maintained and minimize energy use.

To meet these objectives, ANSI/IES RP-8-18 addresses numerous matters integral to the design of lighting systems. For example, Chapter 3 covers calculations; Chapter 5 confronts the planning and design process; Chapter 6 deals with system components; and Chapter 9 outlines maintenance and operations. In all, throughout its nearly-500 pages, the ANSI/IES RP-8-18 document contains 19 chapters and 10 annexes for assuring quality roadway lighting solutions.

ANSI/IES RP-8-18: Recommended Practice For Design And Maintenance Of Roadway And Parking Facility Lighting is available on the ANSI Webstore.

One thought on “ANSI/IES RP-8-18: Design Of Roadway Facility Lighting
  1. I am the Traffic Operations Supervisor for Kitsap County Public Works. We have questions relating to Section – Partial Intersection Lighting.
    1. Does Table 12.2 pavement illuminance criteria apply to all conflicts points including the crosswalks or just the area inside the extension of the primary roadway edges?
    2. Why does paragraph 4 of Section state “The values included in Table 12-2 (Pavement Illumination Criteria for Partial Intersection Lighting) are the recommended average maintained light levels for the area being lighted, based on the road classification and pedestrian volumes” when pedestrian levels are only referenced in Table 12-1 (Pavement Illumination Criteria for Full Intersection Lighting)?
    Also, Section 11.7.2 Lighting Criteria references Section and Tables 11-2, 11-3, and 11-4 but appear to be missing from publication.

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