Managing Selected Transportation Assets: Signals, Lighting, Signs, Pavement Markings, Culverts, and Sidewalks (2007)

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35 OVERVIEW Roadway lighting promotes safer, more efficient, and more comfortable and convenient travel at night for vehicles, pedes- trians, and cyclists. By illuminating the surface and adjacent features of the roadway or sidewalk users may better see conditions some distance ahead. This improved visibility con- tributes to safety (fewer crashes). The FHWA has determined that “installing roadway lighting has the highest benefit–cost ratio of all safety improvements,” and several other countries have reported a reduction of 20% to 30% in nighttime crashes after roadway lighting was installed (Hasson and Lutkevich 2002). Lighting can also play a role in adding beauty and influencing the nighttime visual character of an historic district or urban village, and in helping to reduce crime. Agencies participating in the study survey ranked the trans- portation objectives that are served by roadway lighting in priority order, as given in Table 8. Meeting these objectives requires agencies to observe stan- dards, technical recommendations, and guidelines from a variety of sources. Figures 20 and 21 present the agencies’ judgments of those sources of guidance that are the important drivers of engineering and management decisions regarding roadway lighting. These results are shown for two key aspects of asset management: new construction and installation, and maintenance and rehabilitation, respectively. The importance of national standards, and especially in- dividual agency policies, standards, guidelines, and proce- dures, is evident in these results. National standards include the AASHTO Roadway Lighting Design Guide (2005), lighting needs of pedestrians in walking areas and at inter- sections and crossings (A Policy on Geometric Design . . . 2004), luminaire structural supports (Standard Specifica- tions for Structural Supports . . . 2001), and safe provision of lighting support structures in the roadside (Roadway Design Guide 2002), as well as guidance issued by the Illuminating Engineering Society of North America (“IESNA Profile . . .” 2006). As an example of up-to-date agency practice, the Iowa DOT is currently sponsoring development of a practical road- way lighting design guide for different types of roads in rural and urban settings that will address several management needs of state and local agencies (“Developing a Rural and Urban . . .” 2005): • An application guide (matrix) to recommend priority locations for lighting installation based on considerations of roadway, land use, safety, and traffic conditions. • An evaluation of the criteria used to determine when lighting is warranted at a location, and when alternatives may be acceptable. • A manual describing a standard design layout for use by state and local agencies, consulting engineers, and contractors. • An evaluation of the relative safety benefits of lighting versus those of alternatives such as rumble strips, flash- ers, better signage, etc. • Consideration of other factors that affect lighting effec- tiveness; for example, lighting configuration (destina- tion versus full lighting), amount of luminance, and placement. • Recommendations on dealing with glare from locations outside the roadway boundary (e.g., lighted parking lots). Quebec employs five basic guidelines for lighting installa- tion at intersections (Bruneau and Morin 2005): • All intersections in urban and near-urban areas will have lighting. • The number of luminaires and lighting levels is based on intersection traffic volumes from all approaches. • Lighting should be installed if an intersection has had an annual average of three night accidents during the previous three years. • Lighting may be installed if it is logical to expect that there will be a reduced risk of nighttime accidents in the intersection. • Roadway lighting must be installed at rural intersections where traffic signals exist or are expected to be installed in the near future. Quebec has studied the safety performance of rural lighted intersections as compared with unlit locations. It has observed a 39% reduction in the night accident rate for intersections with Quebec’s standard lighting as compared with intersections operating in darkness (Bruneau and Morin 2005). In addition to considerations of motorist, pedestrian, and bicyclist safety, security, and convenience, as well as aesthetics in urban areas, roadway lighting is also designed CHAPTER THREE ROADWAY LIGHTING

No Response Other Agency Guidelines Public Policy Natíl. Standards Statutes Percentage of Responses 0 20 40 60 80 100 FIGURE 21 Technical management guidance for maintenance and rehabilitation of roadway lighting. No Response Other Agency Guidelines Public Policy Nat’l. Standards Statutes Percentage of Responses 0 20 40 60 80 100 FIGURE 20 Technical management guidance for new installations of roadway lighting. 36 Rank Factor 1 Public safety; accident and accident risk reduction 2 Comfort and convenience of the traveling public (motorists, pedestrians, cyclists) 3 More efficient travel; maintain intended flow and operating speed; reduce travel time 4 Preservation of the existing road infrastructure; reduced agency life-cycle costs 5 Road aesthetics and appeal 6 Crime prevention TABLE 8 PRIORITY OF TRANSPORTATION OBJECTIVES SERVED BY ROADWAY LIGHTING

37 for environmental reasons; for example, reduction in light pollution and protection of wildlife movements. The recent international scan of European road lighting practices, sponsored by AASHTO, FHWA, and NCHRP, has docu- mented several guidelines to reduce sky glow (Wilken et al. 2001), and implementation of embedded roadway lighting systems and bollard-mounted lights on the adjacent bike path has been tested in Florida to protect baby sea turtles in their journey from their beach nests to the sea (Ellis and Washburn 2003). More generally, researchers in the Netherlands are investigating several types of guidance systems including LEDs, pavement markers, LED post delineators, LED pavement marker stripes, fiber-optic “side sights” that are attached full-length to a guardrail, and fiber optic “end lights” (fiber optic cables in the pavement with ends that extend above the pavement surface at fixed inter- vals, with light emitted from the tips of these ends). These installations are applied where extra guidance is needed in late night. In environmentally sensitive areas, the Dutch use a variety of tailored approaches, including not installing lighting, using lighting that can be dimmed, and investigating lighting as a guidance system as described previously (Wilken et al. 2001). MANAGEMENT PRACTICES Synthesis and AASHTO–FHWA Survey Findings As with traffic signals, maintenance of roadway lighting is often characterized by a sharing of responsibility among public and private organizations. The distribution of work and maintenance management responsibility reported by responding agencies is shown in Figure 22. Although some DOTs, provincial ministries, and local agencies are solely responsible for both overall management as well as conduct of roadway lighting maintenance, many other agencies rely as well on other groups to perform this work. These arrange- ments include outsourcing to private contractors (by all levels of government), and partnerships with other levels of government or, in some cases, with utility companies. In the majority of cases involving outsourcing to private contractors by agencies participating in the survey, these firms do not have management responsibility. This practice contrasts with work performance by other units of government and by the utility companies, in which the performing city, county, or company does exercise management responsibility. Other aspects of asset management practice are revealed through an agencies’ methods of budgeting for preservation, operation, and maintenance of roadway lighting, and its approaches to preserving and maintaining roadway lighting once in service. Survey results for the budgeting method are shown in Figure 23. Explanations of the abbreviated budgeting process descriptions in this figure are given in chapter two. Because agencies could select multiple choices, the percentages in Figure 23 do not sum to 100%. Addressing their methods of budgeting, a large number of responding agencies at all levels of government chose the “previous budget plus adjustments” option and the “staff judgments, political priorities, and citizen demands” option as best describing their processes. These two were often selected in combination with each other, and some- times in conjunction with one or more of the other options shown in Figure 23 as well. The survey results in Figure 23 show that the number and target performance of assets are used to a degree in budgeting, but are not the primary drivers of budget processes among survey respondents. Approaches based on Target (Asset Performance) Drives Budget and Budget (Asset Per- formance) Drives Target each were identified in roughly 20% of the responses; Percent of Inventory Budgeted Annu- ally was checked in less than 10% of the responses. By con- trast, methods based on Adjustments to the Previous Budget and those that involve Staff Professional Judgment, Political Priorities, and Citizen Demands each garnered at least 40% of the responses (bearing in mind that agencies could select more than one approach). The general thrust of these results is complemented by a January 2000 AASHTO survey of roadway safety hardware that was reported by the FHWA (Hensing and Rowshan 2005). When asked whether asset inventory and asset condition were used as the basis of fund- ing allocation, 7 of 39 states (18%) responded affirmatively for lighting inventory, and 10 of 39 (26%), for lighting condition—again, well less than a majority in each case. The corresponding results for supports of signs, signals, and lighting in this AASHTO survey were 6 of 39 states (15%) responded affirmatively that funding allocation is based on supports inventory, and 11 of 39 (28%), that allocation is based on supports condition. A related question in the January 2000 AASHTO survey (Hensing and Rowshan 2005) asked whether state DOTs 0 20 40 60 80 100 Own Agency Private (Outsourced) Other Gov’t. Unit Other Entities No Response Pe rc en ta ge o f R es po ns es Mgmt. Resp. No Mgmt. Resp. FIGURE 22 Responsibility for maintaining roadway lighting once in service.

have a separate budget line item for maintenance of roadway lighting; 17 of 39 agencies (44%) responded affirmatively. The corresponding result for maintenance of sign, signal, and lighting supports was 8 of 39 agencies (21%) respond- ing affirmatively. Although there was no corresponding question for budgeting of new lighting installations, the survey did address tracking and updating of asset inventory. These additional responses are reported in a later section of this chapter. Agencies often described their approaches to preservation and maintenance as well in terms of multiple selections of the items shown in Figure 24. Immediate correction of problems was the most prevalent response, followed by prioritized, worst first, and preventive approaches. 38 Several agencies explained these multiple approaches by differentiating how and when they are used. For example: PREVENTIVE: for control cabinets and switch gear; IMMEDIATE: for cable breaks, knockdowns, and switchgear; CORRECTIVE: for lamp, ballast, and fixture failures; WORST FIRST: for underground breaks from deteriorated sys- tems resulting in failures from salt water and freeze-thaw in win- ter; and DEFERRED MAINTENANCE: on older, deteriorated systems. — NYSDOT Region 10 0 20 40 60 80 100 No Response Other No Maintenance Responsibility Deferred Maintenance Worst First Prioritized—Avail. Res. Corrected Immediately Preventive—Schedule Percentage of Responses FIGURE 24 Approach to maintaining and preserving roadway lighting. 0 20 40 60 80 100 No Response No Specific Approach Other Percent of Total Budget Judgment, Politics Previous + Adjustments Percent Inventory Annually Budget Drives Target Target Drives Budget Percentage of Responses FIGURE 23 Annual budgeting method for preservation and operation of roadway lighting.

39 Highway construction projects call for lighting system re- placement/rehabilitation. — Oregon DOT Each district has its own method. — Texas DOT “Worst first” [is] applied to Critical Pole Replacement. — City of Edmonton “Immediate” [is] applied to emergency safety hazard only. — City of Portland Leased lighting arrangement with utility focuses on achieving lighting repairs done within 72 hours of request. City-maintained lights are inspected once every 2 weeks and, if applicable, repairs are made within 1 week of problem identi- fication. — City of Tampa International Practice International scans of practices in roadway lighting and more broadly in transportation asset management have observed that European road agencies give high priority to lighting (Geiger et al. 2005) and European roads are more brightly lit than U.S. roads (Hasson and Lutkevich 2002). Innovative asset management approaches and attitudes that are applied by European agencies in Finland, Switzerland, France, Bel- gium, and the Netherlands include the following, among other advances identified by the roadway lighting in- ternational scan team (Wilken et al. 2001; Hasson and Lutkevich 2002): • Master lighting plans—Lighting is considered a com- ponent of effective city management. Several European cities have developed master lighting plans to support the public image of the city, help create a desired night- time environment, contribute to urban beautification, improve safety and security, and recognize new devel- opments in lighting technology. The advantage of such plans is that they help coordinate different lighting func- tions, organize the lighting program across different parts of the city, and schedule needed expenditures. • Realistic experimentation and progressive attitude toward technology—The scan team found European lighting solutions to be new, practical, creative, and effective. Examples of advanced devices and systems included dynamic (or variable) lighting levels that depend on time of day, weather, and traffic; vertical illu- mination in crosswalks for more prominent visibility of pedestrians; lighted, in-road traffic guidance systems in lieu of fixed overhead lighting; and energy-absorbing poles in locations where breakaway poles could not be used. The scan team noted a very progressive attitude toward testing and implementing innovative technol- ogy, supported by aggressive research programs in several countries (e.g., visibility research using three- dimensional targets and pavement reflectance research on new paving materials). Experiments are conducted on active roadways, enabling realistic in-service trials and more rapid implementation of new ideas— an approach able to be used owing in part to the lower tendency for litigation as compared with U.S. experience. • Data on crashes and lighting—Police in Zürich, Switzer- land, analyze the causes of accidents and make recom- mendations with respect to lighting. This finding led the scan team to recommend a uniform accident reporting system among U.S. states that includes more accurate descriptions of the lighting conditions at crash scenes. • Equipment quality and maintenance—Lighting equip- ment used by European agencies is of generally higher quality than comparable equipment used in the United States, reducing frequency of outages as well as mainte- nance requirements. Group relamping is done at 3–5 year intervals. A maintenance issue that affects Euro- pean agencies as well as U.S. DOTs is the difficulty of maintaining as-designed photometric performance (i.e., overall luminance levels) when replacing lumi- naires or other system components. Lighting-related findings of the international scan that relate to signs and pedestrian crosswalks (discussed in chap- ters four and seven, respectively) were as follows: • Moving away from lighted signs—Finland is eliminat- ing fixed-sign lighting and moving to high-performance, micro-prismatic sign sheeting. France is likewise elimi- nating sign lighting, but continuing to use engineering- grade retroreflective sheeting. • Vertical lighting of pedestrians in crosswalks—Switzer- land is now lighting crosswalks from the side to provide greater visibility of pedestrians to drivers. This approach has resulted in a two-thirds reduction in pedestrian– vehicle crashes, although minor vehicle–vehicle crashes have increased as a result of sudden stops before the crosswalk. Although France has confirmed the visibility benefits of the Swiss approach, they caution that pedes- trians may believe they are seen by drivers regardless of ambient lighting and weather conditions, even if they are not exactly within the crosswalk. MEASURING ASSET PERFORMANCE Synthesis Survey Findings The information provided by agencies on performance measurement of roadway lighting is summarized in Fig- ure 25, based on categories of performance factors similar to those described in chapter two. Physical measures of non- functioning items (e.g., is the light lit?), asset age, and customer complaints were cited the most often by respond- ing agencies. Many agencies also reported structural condi- tion of supports and corrosion as key items, expressed in

More Than Once A Year Annually Biennially Less Freq Than Biennially FIGURE 26 Frequency of physical condition assessments of roadway lighting. 40 physical as well as qualitative terms. The frequencies with which physical measures are addressed are shown in Fig- ure 26. Almost half of the reporting agencies assess lighting condition more than once a year, and almost two-thirds of these agencies at least annually. The methods used by responding agencies to assess light- ing condition and performance are reported in Figure 27. Visual inspections and customer complaints are by far the most common methods used. Under “Other” methods, Maryland reported use of global positioning systems (GPS) to record the number of lighting units, and the city of Edmonton mentioned ultrasonic nondestructive testing of system components. Edmonton noted its five-year condition assessment program, and Colorado Region 3 included maintenance patrol inspec- tions as a source of condition data. PHYS: Structural Condition PHYS: Corrosion PHYS: Not Functioning PHYS: Use- or Time-Related PHYS: Other Asset Age Hours in Service Operational Performance System Reliability Performance or Health Index QUAL: Structural Condition QUAL: Corrosion QUAL: Not Functioning QUAL: Use- or Time-Related QUAL: Other Asset Value Customer Complaints Customer Surveys Other No Response 0 20 10 40 60 80 30 50 70 90 100 Percentage of Responses FIGURE 25 Measuring performance of roadway lighting. PHYS = physical; QUAL = qualitative.

41 No Response No Info. Collected Other Customer Complaints Customer Surveys Non-Destructive Testing Physical Measurement Photo, Video Visual Inspection 0 20 40 60 80 100 Percentage of Responses FIGURE 27 Data collection methods for condition and performance of roadway lighting. Technical and Human Factors Aspects of Performance The technical aspects of illumination and related measures are discussed in the literature (e.g., Lewin 1999; Roadway Light- ing Design Guide, Appendix B 2005). Illuminance is the light output striking a given area, measured in lumens per area lit. Its units of measurement are either lux in the metric system (abbreviated lx, in lumens per meter2), or footcandles in U.S. conventional units (abbreviated fc, in lumens per ft2). Illumi- nance depends on both the light emitted by the lamp and the distance of the light source from the roadway surface (Road- way Lighting Design Guide 2005). It is an absolute measure and is therefore independent of the perceptions of drivers. How drivers perceive roadway lighting and related measures such as reaction time to perceived targets depend on other factors in addition to illuminance, including ambient or overall lighting level and the color or wavelengths of the roadway lighting, as well as the vision and ability to react of the driver. Ambient or overall light conditions are described as follows (Lewin 1999; Bullough and Rea 2004): • Photopic: high ambient light levels, as in daylight. • Scotopic: darkness or very low light levels, as in star- light levels at night. • Mesopic: ambient condition between photopic and scotopic, as in twilight or nighttime under even partial moonlight. Mesopic conditions also exist at typical street or highway lighting levels. As ambient conditions transition from photopic to scotopic, the vision of the human eye undergoes changes. Its ability to see yellow and red light diminishes, although its sensitivity to blue light increases. Its vision in mesopic con- ditions lies between its responses in photopic and scotopic light levels. These changes in vision are the result of the eye’s two types of photoreceptors: cones, which are most active in photopic light, and rods, which respond to scotopic conditions. Both cones and rods are active when driving at night in mesopic conditions. Because cones are associated primarily with vision directly ahead (foveal vision) and rods with peripheral vision the design of roadway lighting must account for drivers’ abilities to see both straight ahead and to the side. The problem goes beyond lumen output and must consider color or wavelength of lighting, configuration of the luminaires (e.g., their location and height, and whether they cast light on the roadway itself or toward the roadside); the type of lamp that best satisfies desired lighting characteristics; and life-cycle characteristics of the lamp, including service life and cost (Lewin 1999; Hasson and Lutkevich 2002; Bullough and Rea 2004). Road lighting design and management therefore depend on balancing the range of visibility requirements of different drivers, the realistic capabilities of available lighting tech- nology, and their life-cycle feasibility. Visibility and driver reaction time need to be understood in actual (complex) visual situations. Lighting that is specified based on photopic conditions may need to be evaluated using additional criteria for mesopic conditions. Unintended consequences need to be avoided; for example, lighting designed to assist peripheral vision in mesopic conditions may cause distractions to drivers in other conditions, such as fog and falling snow. Lighting solutions have therefore been proposed based on a comprehensive systems approach in which several ele- ments—for example, fixed roadway lighting, vehicle head- lamp lighting, pavement markings, signals, and signs—are assembled to provide a total and balanced visual solution (Bullough and Rea 2004).

ASSET SERVICE LIFE Information on service life was obtained in the study survey for three major components of lighting systems: the struc- tural supports (poles and arms), lamps, and other items (e.g., ballast, photocells, and control panels). Responding agen- cies were also asked to identify how they would determine service-life values. Responses to this question are shown in Figure 28. Among the 35% of reporting agencies that iden- tified at least one method, their emphasis was on collective agency knowledge, whether represented by their experi- ence with roadway lighting infrastructure (e.g., a database of observed historical service lives) or by the professional judgment of their staffs. Manufacturer’s data were also noted as a source of information, but to a somewhat lesser degree. A comprehensive statement of all of the items for which estimated service lives were reported is given in Table 9. Examples of histograms showing service-life distributions for those items with the most numerous responses are given in Figures 29 through 34. The labels on the horizontal axis in these figures give the upper values of each range of service- life data. For example, if these labels are 0, 5, 10, 15 . . . , then the column labeled 5 shows the number of responses for estimated service life of zero to 5 years; the column labeled 10, the number of responses for estimated service life of more than 5 to 10 years; the column labeled 15, the number of re- sponses for estimated service life is more than 10 to 15 years; and so forth. It should be noted again that the data in Table 9 and Figures 29 through 34 may be derived in part from the professional judgment of agency personnel. The structural performance of luminaire supports has also been a topic of recent interest. Research has resulted in up- dated guidelines and specifications for structural supports 42 (Standard Specifications for Structural Supports . . . 2001, updated in 2003; Fouad et al. 2003). To apply the service-life concept in asset management, a method is needed to determine where an asset is in its service life—that is, how much life is consumed and how much remains. Agencies were presented with a number of ways to determine the current status of an asset regarding its service life and asked to rank each method by relevance to their agency. The result is shown in Table 10. Note that two instances of tie values occurred in this particular ranking process. The “other factors” shown in Table 10 included two amplifying comments: • The city of Portland, Oregon, does group relamping of lamps; and • The response by the city of Tampa, Florida (to the effect that the agency does not use or monitor service life for this asset), pertains to leased lighting, which is main- tained by the utility company. On the related issue of identifying the extension in service life owing to maintenance, only one of the 32 reporting agen- cies responded affirmatively. The Oregon DOT reported that this effect was taken into account in its replacement of existing metal halide lamps with new high-pressure sodium luminaires. INFORMATION TECHNOLOGY SUPPORT Agencies participating in the study survey identified their key IT capabilities as shown in Figure 35. Many (but not all) agencies have an inventory of roadway lighting assets accompanied by information on location. Recommendations No Response Do Not Use Service Life Other Manufacturer’s Data Professional Judgment Literature Agency Experience LCC Analyses Model Develop, MIS 0 20 40 60 80 100 Percentage of Responses FIGURE 28 Sources for determining service lives of roadway lighting components. MIS = management information systems; LCC = life-cycle cost.

43 8 7 6 N o. o f R es po ns es 5 4 3 2 1 0 0 5 10 15 20 25 30 35 40 45 50 Estimated Service Life, Years FIGURE 29 Estimated service life of tubular steel mast arm for roadway lighting. Component and Material No. of Responses Minimu m (Years) Maximu m (Years) Mean (Years) Median (Years) Mode (Years) Structural Com ponents Tubular steel 12 10 40 25.4 25 25 Tubular alum inum 9 1 0 4 0 26.1 25 30 Cast me tal 2 1 5 3 0 22.5 22.5 — Wood posts 2 2 5 4 0 32.5 32.5 — High ma st or tower 11 10 50 28.6 30 30 Lamps Incandescent 3 1 5 2 1 Mercury vapor 6 3 5 4 4 High-pressure sodium 15 1 6 3.6 4 Low-pressure sodium 3 1 5 3 4 Metal halide 9 1 5 2.9 3 Fluorescent 1 — — 5 — — Other Com ponents Ballast 9 2 25 9.7 7.5 10 Photocells 11 1 1 0 5.2 5 1 4 5 4 2 5 Control panels 7 1 0 2 5 18.2 20 20 Lu mi naires 2 5 25 16.25 16.25 — Notes: —, value is undefined for the particular distribution. When distribution is based on only one data point, its value is shown in the Mean column. TABLE 9 ESTIMATED SERVICE LIVES OF ROADWAY LIGHTING COMPONENTS

87 6 N o. o f R es po ns es 5 4 3 2 1 0 0 1 2 3 4 5 6 7 8 9 10 Estimated Service Life, Years FIGURE 32 Estimated service life of high-pressure sodium vapor lamps for roadway lighting. 8 7 6 N o. o f R es po ns es 5 4 3 2 1 0 0 5 10 15 20 25 30 35 40 45 50 Estimated Service Life, Years FIGURE 31 Estimated service life of high mast or tower for roadway lighting. 44 8 7 6 N o. o f R es po ns es 5 4 3 2 1 0 0 5 10 15 20 25 30 35 40 45 50 Estimated Service Life, Years FIGURE 30 Estimated service life of tubular aluminum mast arm for roadway lighting.

87 6 N o. o f R es po ns es 5 4 3 2 1 0 0 1 2 3 4 5 6 7 8 9 10 Estimated Service Life, Years FIGURE 34 Estimated service life of photocells used in roadway lighting. 8 7 6 N o. o f R es po ns es 5 4 3 2 1 0 0 2.5 5 7.5 10 12.5 15 17.5 20 22.5 25 Estimated Service Life, Years FIGURE 33 Estimated service life of ballast used in roadway lighting. Rank Factor 1 Assets are repaired or replaced as soon as they fail without regard to service life 1 The agency does not use/does not monitor service life for this type of asset 3 Monitor condition of the asset occasionally 4 Compare current age of asset with the maximum age that defines service life 5 Service life is often determined more by functional obsolescence than by wear and tear 6 Monitor condition of the asset on a periodic schedule 7 Compare service hours to date with the maximum number of service hours that defines service life 8 Assets are replaced on a preventive maintenance schedule without regard to where they are in their service life 9 Apply deterioration models to estimate where the asset is on “the curve” 9 Other factors TABLE 10 RANKING OF METHODS TO DETERMINE WHERE ROADWAY LIGHTING ASSETS ARE IN THEIR SERVICE LIVES

46 0 10 20 30 40 50 60 70 80 90 100 No Response None of the Above Other Historical Database PMs, Dashboards, Accountability GIS Maps, Reports GIS Interface Est. Asset Impacts on Public Track Public Comments Cost Models for Treatments Other Optimization Procedures Benefit-Cost, LCC Decision Rules or Trees Inspector Recommendations Established Mntce. Schedule Deterioration Models Anticipated Service Life Dates of Inspections, Assess. Asset Age Usage, Traffic Volume Photograph Current Condition, Performance GPS Coordinates Location (e.g., Rte-Milepost) Number/Quantity of Asset Percentage of Responses FIGURE 35 IT capabilities to help manage roadway lighting. GPS = global positioning system; LCC = life-cycle cost; GIS = geographic information system; PMs = performance measures. of inspectors were also reported by a number of agencies. Less than 5% of responding agencies reported that they tracked anticipated service life. No strong distinctions in the findings represented by Figure 35 were observed among different levels of government. By comparison, responses to the January 2000 AASHTO survey (Hensing and Rowshan 2005) indicated that 15 of 39 agencies (38%) had an inven- tory of roadway lighting, and most of these updated their inventory by manual survey. Agencies characterized their IT systems for roadway light- ing as shown in Figure 36. Most agencies reported using broad-based management systems, such as maintenance man- agement systems, followed by workbooks or spreadsheets and simple programs. The agencies that reported using a roadway lighting management system or a maintenance management or transportation infrastructure asset management system that includes roadway lighting are listed in here. • Roadway Lighting Management System – Colorado DOT Region 4 – City of Edmonton, Alberta. • Maintenance or Asset Management System That In- cludes Roadway Lighting – Florida DOT – Iowa DOT – Minnesota DOT – Ohio DOT – Oregon DOT – Colorado DOT Regions 1, 3, and 5 – City of Edmonton, Alberta – City of Portland, Oregon. KNOWLEDGE GAPS AND RESEARCH NEEDS Synthesis Survey Comments Agencies at all levels identified a number of knowledge gaps and resulting needs for research in their survey responses. These comments have been organized by topic area and compiled and summarized here. • Basic management capabilities—Although information on roadway lighting design exists, agencies reported

47 that roadway lighting had not yet been developed within its asset management framework (Saskatchewan), and that legacy systems for maintenance management did not yet have a road inventory needed for asset manage- ment (Nevada). Research is also needed to better understand the best approach for maintaining street lighting; for example, whether by group relamping or the “break-repair” method (Tampa). • Service lives—Several agencies observed that the cur- rent data on roadway lighting service life is difficult to use because of inconsistencies, wide variability in values, and the strong influence of local conditions. Research is needed to reduce the wide variation and to develop more useable values for different components of roadway lighting (New Brunswick, Colorado Region 3, and Kansas). There is also a need for more consistent measurement and reporting of product relia- bility data (Minnesota). • Nonphysical and physical attributes—Research efforts need to recognize the importance of nonphysical as well as physical measures of condition and perfor- mance. Factors such as the energy cost per light, age of the wiring system, and relative benefits of different types of lamps (e.g., high-pressure sodium versus metal halide) need to be understood. For example, how does the color of the light affect driving and security (Mary- land and Tampa)? What are the roadway and traffic safety improvements gained by installing illumination (Oregon)? • New technology—Technological advances could pro- vide more accurate and efficient management of roadway lighting; for example, through the ability to monitor the operational status of lighting systems from a remote location (Minnesota and Utah), and the development of more efficient and economical light sources [e.g., a reli- able and cost-effective LED source for roadway lighting (Saskatchewan and Portland, Oregon)]. More complete information on existing technology is also needed; for example, a comparison of one manufacturer’s part com- patibility to another’s (Michigan). • Institutional issues—Management capabilities and in- formation availability need to accommodate different institutional arrangements. For example, in a situation where the lighting system is leased, the costs associated with design, engineering, construction, customer service, outages, and maintenance are monitored by the electric utility; information on maintenance and operational his- tory of the leased lighting infrastructure is therefore not now available to the transportation agency (Tampa). • Communicating priority—The urgency of the need to replace deteriorated lighting systems appears not to be well understood within the context of Transportation Improvement Program development in conjunction with the local metropolitan planning organization. Other investment categories are programmed instead (New York Region 10). FHWA, AASHTO, and NCHRP International Scan Based on their review of European roadway lighting practice, the international scan team made several recommendations for consideration by U.S. agencies and research sponsors. Of these, the following recommendations bear most directly on asset management practices in roadway lighting (Wilken et al. 2001). • Develop master lighting plans that help coordinate road- way and urban lighting considering lighting levels, styles, and themes that serve safety, security, and beautification. • Develop a uniform accident reporting system among states that includes more accurate descriptions of the lighting conditions at crash scenes. • Investigate dynamic lighting management to be able to dim lights or turn systems off, and consider alternative lighting systems such as embedded-lighting guidance systems. • Evaluate drivers’ information needs at night—for example, for navigational guidance, stopping distance, object-in-road avoidance, peripheral visibility, and zones of driver attention—considering different lighting levels and traffic volumes. • Further evaluate European standards, practices, and guidelines to determine potential applicability in the United States. • Consider vertical illuminance to improve pedestrian safety in crosswalks and other pedestrian areas, benefiting Other Products or Procedures Workbook, Spreadsheet Simple Program(s) for this Asset Broad-Based MMS, TIAMS, etc. Road Lighting Management System Percentage of Responses 0 20 40 60 80 100 FIGURE 36 Types of analytic tools to support roadway lighting management. MMS = maintenance management system; TIAMS = transportation infrastructure asset management system.

from positive-contrast illumination of pedestrians. [An initial experiment applying this Swiss technique in the United States is described in Hasson et al. (2002)]. • Develop measurement techniques and standards for off-roadway sources of glare and lighting strategies to mitigate adverse effects of this glare. Also, investigate adverse glare effects on pedestrians and bicyclists, bal- ancing their ability to see and their ability to be seen. • Train maintenance personnel in correct procedures to maintain the as-designed lighting levels when replacing system components. • Consider other European practices and research studies in lighting design and component selection such as the following: – Consider quality lighting materials as appropri- ate to improve durability and reduce maintenance requirements. – Investigate energy-absorbing poles as an option for selected applications, taking care to account for 48 the wide range of vehicle mass and speed on U.S. highways. – Conduct research in pavement reflectance to include newer materials and update values in existing reflect- ance guidelines (“R-tables”). Some of these ideas have already been incorporated in the recently updated AASHTO guidance for roadway lighting (Roadway Lighting Design Guide 2005). An entire chapter has been devoted to master lighting plans. Lighting curfews are discussed in the context of modern operation and control of the system, taking advantage of opportunities to turn off or dim lighting as local conditions permit. The guide also emphasizes the need to conduct traffic and lighting studies in support of these initiatives. It is not unreasonable to expect that these and the other recommendations listed previously will continue to be the subjects of future research and im- plementation studies, and to be addressed at conferences, workshops, and other information exchanges.