Illumination Guidelines for Nighttime Highway Work (2003)

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SECTION ONE BACKGROUND, RESEARCH APPROACH, AND RECOMMENDATIONS

SECTION ONE: BACKGROUND, RESEARCH APPROACH, AND RECOMMENDATIONS 1-3 CHAPTER 1 BACKGROUND AND RESEARCH APPROACH BACKGROUND Recently many states have shifted their priority from building new facilities to maintaining and improving those already in existence. Daytime lane closures for rehabilitation work results in heavy congestion on roads already loaded to capacity. The daytime lane closures are also hazardous, costly, and inconvenient for the traveling public. As a result, more construction and rehabilitation work is being per- formed at night when traffic flow is minimal. In addition to several obvious advantages of nighttime work—such as cooler temperatures for equipment and material and fewer traffic problems and delays—there may also be certain dis- advantages. Night work comprises many complex issues and a variety of problems, which include lighting conditions, safety, and effect on quality, worker availability, and admin- istrative decisions. Recent research conducted at the University of Florida has shown lighting as one of the most important factors for night- time construction (1). It has been found that safety in the work zone, traffic control, quality of work, and workers’ morale are directly related to work zone lighting. Limited or restricted visibility is an obvious drawback of nighttime con- struction. However, with adequate levels of light, construc- tion operations can be performed as well at night as they can be during the day. Likewise, the key factors that influence accident rates are the physical conditions of drivers and the light conditions of the environment. The physical conditions of the driver may include conditions such as drowsiness and sensitivity to light glare. Worker injury rate also increases because of the inherent vision impairment associated with nighttime lighting conditions (2). Sufficient lighting of the work area is also important from the point of view of quality. Standard highway lighting, or light from nearby businesses or residences, is generally inadequate to properly light the areas where work is performed. Inadequate lighting results in problems with proper inspection. Work quality is affected because many defect causes, such as shadows, tack spread, and asphalt droppings, cannot be properly controlled (3). In the specifications of many state highway agencies (SHAs), present lighting requirements are minimally defined (e.g., minimum intensity level of 54 lumens per square meter (lx) or 5 ft-candles (fc), sufficient light to permit good work- manship and proper inspection, etc.). Most of these specifi- cations are not only inadequate but also are not standardized. Decisions pertaining to work zone lighting are left to the dis- cretion of the site engineer and the contractor. Moreover, due to the lack of criteria related to average illumination levels and uniformity of illumination, lighting systems cannot be designed satisfactorily. RESEARCH OBJECTIVES Although lighting is the single-most important factor in nighttime construction, it is the least studied. Very little research has been done concerning the proper lighting of construction sites. This research effort aims not only to sug- gest the design of a lighting system based on current site con- ditions, but also to facilitate developing a set of standard guidelines and specifications. The objectives of this proposed research effort are as follows: • To develop guidelines that can be used by public agen- cies and contractors in determining: (a) the types of light sources and (b) the minimum and maximum levels of illumination for a variety of nighttime work in typical highway situations; • To develop guidelines for work zone lighting design; and • To develop guidelines for the use of temporary roadway lighting to provide work zone lighting. RESEARCH APPROACH This study was conducted in two phases. Phase I focused on the development of the Guidelines for Work Zone Illumi- nation and on the Design Guidelines for Work Zone Light- ing. Phase II was performed to obtain additional validation of the guidelines developed in Phase I and to investigate the possibility of using temporary roadway lighting as a source for work zone lighting. The general strategy for developing the illumination guide- lines was to transfer established illumination guidelines from other well-established industry areas to the specific area of transportation construction and maintenance. This was accom- plished by defining the seeing task characteristics of the differ- ent operations within highway construction and maintenance.

1-4 SECTION ONE: BACKGROUND, RESEARCH APPROACH, AND RECOMMENDATIONS Work activities with similar seeing tasks from other indus- tries were matched with the highway tasks. Recommended illumination levels were assigned to the highway activities. Field visits and monitoring of nighttime highway construc- tion and maintenance activities provided data to refine and val- idate the guidelines for work zone illumination. Design guide- lines were developed with the project-level user in mind. Simplicity and ease of use were favored over more compli- cated approaches. In Phase I, a literature review and a survey of industry practice was conducted. Additionally, field visits to night- time highway projects were performed. The objective was to obtain an accurate assessment of the current practices for lighting nighttime highway projects. Of particular interest were existing specifications or standards used by SHAs for specifying the lighting to be used for night work. Phase I also involved the development of guidelines for illuminating nighttime highway work projects. The seeing task requirements for various highway maintenance and con- struction activities were identified and compared with estab- lished lighting standards for other industries and national standards. Illumination requirements for highway activities were developed from this analysis. A lighting design manual of practice was prepared as an aid to the highway construc- tion or maintenance professional for configuring proper work area lighting. The key issues in Phase I were • Understanding the state of current practice of nighttime highway project activity, • Developing illumination requirements for highway proj- ect activities, and • Developing design procedures for configuring highway project work area lighting systems. In Phase II, there were two primary objectives: 1. To expand and validate the findings of Phase I with addi- tional field reviews and contacts with SHAs in various geographic regions and 2. To investigate and develop guidelines for the use of temporary lighting as a source of work area lighting for highway projects. Additional visits to different states were conducted, includ- ing visits to nighttime projects. Draft illumination guidelines were reviewed with state and contractor personnel, and draft standards were checked against current project situations. Design procedures were also reviewed and input was solicited. The use of temporary roadway lighting for work area lighting was investigated. The investigation revealed that the use of temporary roadway lighting was extremely limited. However, one project was identified and a site visit was made to the proj- ect. Nevertheless, guidelines for the use of temporary roadway lighting were developed as a part of Phase II.

SECTION ONE: BACKGROUND, RESEARCH APPROACH, AND RECOMMENDATIONS 1-5 CHAPTER 2 SUMMARY OF FINDINGS AND RECOMMENDATIONS SUMMARY OF FINDINGS The purpose of this research was to develop guidelines for the illumination of nighttime highway work including both construction and maintenance activities. Additionally, the research developed guidelines for highway work area lighting design and investigated the use of temporary roadway lighting in connection with highway construction. These objectives were accomplished by performing a comprehensive literature review and conducting surveys to obtain information on current practice. On-site field visits to nighttime construction projects were also made to many projects located in 11 states. During the field visits, observations of lighting practice and illumina- tion measurements were made. Interviews and discussions with field personnel of the SHAs and the contractors also contributed to the research results. Illumination level guidelines were devel- oped for nighttime highway work activities by comparing the seeing tasks associated with highway work activities with the seeing tasks of other industry activities with established illumi- nation standards. Design procedures were developed for the design of temporary work lighting. The subject of using tem- porary roadway lighting was also researched. The research team defined work zone illumination require- ments in three categories depending on the visibility require- ments of the work tasks. Minimum average illumination levels were suggested for each category. Additionally, lighted area requirements were suggested for slow- and fast-moving con- struction equipment. Glare control guidelines and counter- measures were also developed as an integral part of the illumi- nation guidelines. The recommendations were field tested in a demonstration project that validated that the illumination stan- dards were achievable with little additional cost to the project. A simplified design approach was developed for the design of work zone lighting systems. Standard lighting configura- tions were also developed to assist field personnel in setting up appropriate work area illumination and for configuring equipment lighting. The subject of using temporary roadway lighting to illumi- nate highway construction work areas was researched to the extent possible. Limited project examples were found but did indicate the basic design and implementation considerations. The conclusion of this study is that nighttime highway work can be performed safely and with economy and quality com- parable to that performed in the daytime. The essential critical factor is proper illumination. This study offers information that can assist highway agencies in establishing standards and pro- cedures for illumination of nighttime highway work activities. The two keys to implementation are as follows: 1. Establishing organizational standards and 2. Training SHA and contractor personnel. RECOMMENDATIONS The following baseline recommendations have emerged as a result of this study: 1. There is a need for a uniform national standard for high- way work area illumination. AASHTO should consider developing this study based on the findings of a recom- mended illumination standard that could be adopted by its member states. 2. There is a real need for improvements in manufacturer- installed equipment lighting. AASHTO should encour- age equipment manufacturers to offer appropriate night- time operational lighting as optional equipment. 3. The use of temporary roadway lighting may grow. The Roadway Lighting Committee of the Illuminating Engineering Society (IES) of North America should consider including a discussion of temporary roadway lighting in the Roadway Lighting Practice Manual (4). 4. AASHTO or the FHWA should consider sponsoring the development of a basic course on Work Area Illu- mination. The course content could be used by SHAs as a basic training tool for their own personnel and for contractor personnel. ORGANIZATION OF THE REPORT This report presents research findings in four separate and distinct sections: • SECTION ONE: Background, Research Approach, and Recommendations

1-6 SECTION ONE: BACKGROUND, RESEARCH APPROACH, AND RECOMMENDATIONS • SECTION TWO: Illumination Guidelines for Night- time Highway Work • SECTION THREE: Guidelines for Work Zone Illumi- nation Design • SECTION FOUR: Guidelines for the Use of Temporary Roadway Lighting Sections One, Two, and Three focus on different aspects of the general topic of lighting nighttime highway work activities. To facilitate the use of these individual sections, they have been structured more or less as “stand-alone” doc- uments within this report. REFERENCES 1. Ellis, R., Herbsman, Z., and Kumar A., “Developing Night Operations in Florida.” Florida Department of Transportation, FL/DOT/RMC/0548/3543 (Dec. 1991). 2. California Department of Transportation, “Highway Maintenance Activities During Low-Volume Traffic Hours.” Report to Leg- islature (March 1988). 3. Hinze, J. and Carlisle, D., “Variables Impacted by Nighttime Con- struction Projects.” Final Report TNW 90-07, Transportation Northwest, University of Washington, Seattle, WA (Feb. 1990). 4. Illumination Engineering Society of North America, American Standard Practice for Roadway Lighting RP-8-00, New York, NY (1999).