Lighting Practices for Isolated Rural Intersections (2022)

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21   Responsibility for Installation and Operation Survey participants were asked what organizations have installed lighting for isolated rural intersections within their states. The highest responses to this question indicated that the state DOT or its contractors performed this installation (Figure 16). Many localities (counties, cities, towns, or villages) maintain roads in rural areas as well and this is reflected in the high percentage of responses indicating this in Figure 16. Many lighting systems, because of the need to involve the electric utility in bringing power to the location, are installed by the electric utility who then can lease the lighting system to the state or local government. Electric utilities do not design lighting for roadways, but follow the directives of the state or local agency on whose behalf the lighting is installed. Among the “other” responses to this question included commercial devel- opers and combinations of municipal governments and utilities. Installing the lighting does not necessarily mean that the system is owned by that organiza- tion. Survey participants were also asked to describe what organizations own the lighting along isolated rural intersections in their states. Often those systems are owned by the state DOTs, but local municipalities and electric utilities also own a substantial proportion of lighting systems at rural intersections (Figure 17). “Other” responses included commercial developers or stated that ownership was dependent on the specific location of the intersection. Regarding the maintenance of isolated rural intersection lighting, the participants in the survey were also asked to identify what organization or organizations maintain these systems (Figure 18). C H A P T E R 5 Installation, Operation, and Maintenance Chapter Summary • Lighting systems at isolated rural intersections are mainly installed, owned, and operated by state DOTs and local municipalities, depending on the road on which they are installed. • Electric utilities also own and maintain a large proportion of lighting systems in rural intersections, but do not make design decisions about appropriate lighting. • Most maintenance of rural intersection lighting is done on an ad hoc basis after equipment breaks or lights burn out. Complaints from localities and the public are an important way transportation agencies learn about maintenance issues. Few agencies use regular maintenance schedules. • Adaptive lighting for rural intersections is largely untried, although some evidence suggests it would be an effective strategy in some locations.

22 Lighting Practices for Isolated Rural Intersections Figure 16. Responses to “What organization(s) have installed isolated rural intersection lighting in your agency’s jurisdiction?” Figure 17. Responses to “What entity(ies) own the isolated rural intersection lighting in your agency’s jurisdiction?” Figure 18. Responses to “Who is responsible for maintenance of isolated rural intersection lighting in your agency’s jurisdiction?”

Installation, Operation, and Maintenance 23   Similar to the trends in Figures 16 and 17, Figure 18 reveals that state DOTs and local municipal- ities are most often responsible for maintaining rural intersection lighting, followed by electric utilities. In some cases, state DOTs share maintenance responsibilities with local governments. Factors Affecting Maintenance and Operation Keeping lighting systems for isolated rural intersections working is challenging because of the relatively remote and distant nature of these locations. In some rural areas, growth from nearby trees can hamper the performance of the lighting system, and trimming trees and foliage is an important maintenance activity (Torbic et al. 2015; Findlay 2017), but no other aspects of maintenance were identified in the review of the literature and published policies on rural intersection lighting. Survey respondents were asked what factors determined the need to maintain (i.e., repair or replace) lighting at isolated rural intersections (Figure 19). Answers receiving the most responses were related to broken poles (95%), luminaires (90%), or mast arms (79%), and burned-out lights (93%), suggesting that much maintenance is performed as needed. Among the “other” responses, only 7% indicated that agencies had a specific maintenance schedule for repairing or replacing lights at rural intersections. Also underscoring the mostly ad hoc nature of lighting system maintenance at isolated rural intersections is the percentage (71%) of responses identi- fying complaints from local municipalities or the public about rural lighting systems that were not working properly. In general, if a light appeared to be working properly, even if its output were reduced because of lumen depreciation (the gradual reduction in light output experienced by a lighting system over its useful life) or by dirt accumulation, it does not seem likely that it would be given maintenance attention. Another potential issue not addressed by respondents to this question, but mentioned with regard to solar power, is that electric service in remote loca- tions can present challenges to maintaining electrical service to rural lighting. Because of the increasing concern and awareness of light pollution (see the previous chapter) from roadway lighting, agencies participating in the survey were asked if they had ever removed any isolated rural intersection lighting (Figure 20) with no plans to replace them. Only two agencies (5%) had ever done this; one was in response to a statewide effort to review and remove lighting that did not contribute to safety or visibility. Figure 19. Responses to “What determines the need in your agency to replace/ repair isolated rural intersection lighting?”

24 Lighting Practices for Isolated Rural Intersections Adaptive Lighting at Isolated Rural Intersections As seen from the responses to the question about lighting equipment and hardware (Figure 11), photocell control of rural intersection lighting from dusk to dawn is common. This is also borne out by responses to the question about whether any respondents had used adaptive lighting strate- gies in isolated rural intersection lighting. Adaptive lighting (sometimes called dynamic lighting [Bullough 2010]) involves the use of reduced light output during times the illuminated location is less active or has a lower requirement for lighting. IES (2018) recommendations now include provisions for adaptive lighting. As shown in Figure 21, very few agencies (5%) have used adaptive lighting approaches in rural intersections and when they did it was used only on a test or trial basis. Traffic count data over the nighttime hours show a consistent pattern where traffic and even pedestrian use is much lower after certain hours, such as after midnight. It may be possible there- fore to reduce light output during these less active hours without substantially affecting the overall safety outcomes of road lighting in some situations. For example, Bullough and Rea (2011) estimated that re-allocating the lighting energy for a rural intersection by increasing light levels during the 4 busiest hours of the night and reducing levels during the remaining 8 hours could nearly double the overall nighttime crash reduction. These research findings would need to be confirmed in prac- tice before policies allowing such adaptive lighting implementations could be developed. Figure 20. Responses to “Has your agency ever removed or overseen the removal of isolated rural intersection lighting without planning to replace it?” Figure 21. Responses to “Has your agency used adaptive control strategies (e.g., reducing light output after midnight, using motion sensors, etc.) for any isolated rural intersection lighting?”