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

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Based on the survey of U.S. and Canadian transportation agencies that was conducted as part of this study, and a review of related material, a picture emerges of considerable interest and activity to develop stronger management approaches for transportation infrastructure assets, but with a recognition that some basic information and capabilities are currently lacking. The literature review indicates that management of these assets can be complicated in several ways. • From an engineering and technical standpoint, selected assets comprise a number of components and materials, serve in many different environments across the United States and Canada, and are subject to many different types of deterioration. Developing models that ade- quately explain these deterioration mechanisms and that can predict service lives for the complete range of pos- sible conditions is a major challenge. This complexity is true for the physical and chemical processes that affect culverts; the compatibility issues that can affect signal and lighting systems; and the traffic, weather, dirt, solar radiation, and other factors that affect the retroreflectivity of signs and pavement markings. • From a human factors perspective, the selected assets that affect mobility and safety can have complicated impacts that are still being researched. The increase in the elderly population has already been recognized in ongoing work to ensure that signs, pavement markings, traffic signals, and roadway lighting are helpful to all driver and pedestrian populations. Care must be taken to enhance visibility at night and driver comprehension of messages and guidance provided by these devices, avoiding confusion and unintended effects. • From an organizational, institutional, and procedural view, selected assets present challenges in management, coordination, and data compilation. Responsibility for these assets is typically diffused among public- and private-sector organizations, complicating the ability to understand the “big picture.” Agencies that responded to the survey were clearly inter- ested in the management of these selected assets. Several have already developed management systems specifically directed at one or more of these classes of infrastructure. Others have incorporated these selected assets within agency-wide asset management systems or enhanced maintenance management systems. Others are now in the process of developing an asset 134 management approach for these assets. At a minimum, agen- cies rely on existing maintenance management systems or other analytic and data gathering tools such as spreadsheet workbooks and paper log books to track and manage these selected assets. Agencies that responded to the survey agreed substantially on why these selected assets should be managed. Many pro- vided exactly the same or very similar rankings of the trans- portation goals served by these assets. However, estimates of technical data such as asset service life varied across agencies. Although there is a basic pool of information that could form the nucleus of an asset management approach, these agencies reported that additional work is needed in a number of areas. Specific findings and conclusions of the study follow. • State of knowledge. A body of knowledge exists that de- scribes the performance of the selected assets, methods of inspection, available techniques for maintenance and rehabilitation, and other aspects of asset management. However, many agencies believe that this information is variable, to some degree inconsistently defined, and incomplete. The acceptability and use of this knowledge is therefore not as extensive as might be expected. Examples of this variability and inconsistency are easily seen in the service-life data that have been compiled in the study survey. • Inventory. The lack of an inventory of these selected assets was viewed by many agencies as one of the key issues to address. Developing an inventory database itself is not the main problem, although several agencies mentioned this as a need within their own organizations. Rather, the heart of the matter is how to keep the inven- tory current and accurate. In addition to the financial and human resources needed, a key challenge is the con- stantly changing status of these assets. Customer calls arrive daily to report damaged or missing assets. Con- struction projects and maintenance continually repair or replace these assets. Manufacturers offer a continual stream of new products and updates for several of these assets. Legacy management systems may not include the types of data and frequency of update needed to track the inventory of these assets effectively. The need for a comprehensive, accurate, and current inventory, including data on number and location of assets, their age, maintenance and cost histories, current condition CHAPTER NINE CONCLUSIONS

135 and history, performance, inspection schedule, inspec- tor’s recommendations, and so forth, is seen as a basic step to understanding the service life of assets and the best approaches to their management over time. • Management capabilities and information. Although research continues on understanding and modeling ser- vice-life behavior of these assets and implications for performance, agencies participating in the survey men- tioned several management capabilities and types of in- formation that are needed. – One key theme across these assets was the need for standardization—in measures of condition and per- formance, in measurement techniques, and in thresh- old values or criteria for determining when an asset has failed. Greater uniformity was felt to be a step- ping stone to more consistent values of service life and to more effective measurement and reporting of product reliability in these assets. – Service lives and decision criteria such as minimum ac- ceptable values need to be evaluated under actual field conditions. A related need is to better understand the actual needs of drivers, cyclists, or pedestrians regard- ing selected asset attributes under different conditions (day vs. night, weather, ambient lighting, background color, etc.). – Additional information and modeling tools would provide better decision support. Agencies mentioned models to help determine best maintenance policies (e.g., group replacement versus “break-repair”), and tools and information to conduct benefit-cost and life- cycle analyses of alternative materials and products. – Simple, practical, streamlined tools could help agencies make investment decisions more easily, quickly, and efficiently. For example, although asset condition, per- formance, and service life are recognized as functions of several variables that in some cases are site-specific, agencies do not have the time or resources to conduct site inspections for every management decision. Man- agers need tools and procedures that embody the effects of these many variables within easy-to-use devices such as matrices or survival curves. • Beyond physical condition. Several agencies pointed out that the performance and service lives of these selected assets need to be understood in terms that go beyond physical condition. These comments are essentially at two levels: – At one level is the performance of a specific asset component or product. Because signals and lighting involve electronic components, their performance may be better gauged by measures such as functional obsolescence rather than the deterioration of a piece of hardware. Also, the energy costs of competing components are useful to know. – At a second level is the performance of the asset overall and its implications for the general public, not just motorists. Examples for different assets in- clude the benefits of road and sidewalk illumination, the effect of the color of light on driving and secu- rity, the minimum retroreflectivity needed by differ- ent groups of drivers in signs and pavement mark- ings, and the performance of culverts in preventing flooding as land use has evolved. • A dynamic commercial environment. For many of these assets, manufacturers continue to produce a stream of new products and updates, as noted earlier. Although these advances offer many potential benefits, they com- plicate the job of the asset manager. New methods and arrangements are needed to help agency asset managers field-verify existing products while dealing with the in- troduction of new products. Among the ideas that were suggested by survey respondents were the integration of manufacturers’ data into agency asset management databases, tracking the evolution of materials attributes both at a component and a system level, standardizing the determination of service life and reliability (as noted earlier), and obtaining sufficient information to enable comparisons of one manufacturer’s part compatibility to another. • Institutional factors. Almost all of these assets are maintained through institutional arrangements that potentially involve different public- and private-sector entities. Selected assets tend to be maintained through agreements with other levels of government and, se- lectively, with other private groups such as property owners or utility companies. These arrangements have implications for an agency’s ability to be aware of cur- rent condition, maintenance history, and cost history; to enforce maintenance standards and requirements; and to communicate the current asset condition accu- rately to stakeholders and the public. Moreover, these allocations of maintenance responsibility vary across the country and may be embodied in state law. It is therefore difficult to attempt to move toward more uniformity in practice, and to share data on these insti- tutional arrangements on a common basis. • New technology. Several agencies recognized that new technology potentially offers benefits in the management of selected assets. Technological solutions not only offer the possibility of improved, more economical perfor- mance, but they also could address some of the resource limitation issues (e.g., regarding inspections of assets) discussed previously. Examples included remote moni- toring of the status of lighting systems, more efficient lighting based on light-emitting diode sources, lower- cost and more efficient ways to evaluate sign reflectivity, and new materials for rehabilitating culvert pipe. Agen- cies also recognized the need to evaluate new products under field conditions; for example, effects of wood preservative and deicing salt on retroreflective sheeting. • Better communication of priority. Communicating the pri- ority of selected assets needs to be strengthened, both to inform resource allocation decisions on investments across assets and to obtain the additional resources needed to improve management practice for each selected asset.