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PUBLIC BENEFITS OF HIGHWAY SYSTEM PRESERVATION AND MAINTENANCE SUMMARY Maintenance is work done to keep facilities and equipment in a state of repair or working ef- ficiently. Many professionals responsible for highway management assert that this labor is regularly required to preserve facilities, even when they appear to be in good condition, and that its neglect can accelerate wear and aging, early onset of excessively rough pavements, corrosion on bridges, and other symptoms of unsatisfactory system performance. This report, prepared under the auspices of the NCHRP, is a synthesis of current practices for measuring and articulating the benefits of highway system preservation and mainte- nance, and of communicating those benefits in terms that are understandable and meaningful to stakeholdersâroad users, elected officials, and others who have an interest in the systemâs performance. The study focuses particularly on pavements and bridges. The report is based on a study that included a review of published literature on mainte- nance benefits measurement and communication, a formal survey of U.S. state highway agencies, and informal interviews and discussions with a range of individuals engaged in highway system management. The formal survey was sent to agencies in 50 states and the District of Columbia, with 19 agencies responding. Precise definitions of âmaintenanceâ and categories of work comprising maintenance vary among segments of the professional community and the general public. Many engi- neers, for example, define maintenance as any action required to keep a facility or its parts functioning as they were originally designed and constructed to do. The Government Ac- counting Standards Board, which influences how expenses appear in an agencyâs financial statements, defines maintenance as the act of keeping fixed assets in an acceptable condi- tion; that is, keeping conditions at satisfactory, rather than initial design levels. For some professionals, maintenance means only relatively low-cost treatments; more aggressive ac- tion is termed ârepair,â ârenewal,â ârehabilitation,â or âreconstruction.â âPreventive maintenanceâ (PM), for many people, is work done before there is a problem; for example, replacing a carâs tires before they fail inspection. However, highway engineers often apply the term to actions that are taken when certain symptoms of larger problems ap- pear; for example, applying thin overlays to cracked pavements. Failure to perform PM pre- sumably accelerates deterioration and advances the time when rehabilitation is required. âPreservationâ extends the life of a pavement or other highway system component. This report focuses on work that is performed in anticipation of major problems, includ- ing preservation activities, and it uses the term maintenance to distinguish such work from repair, renewal, and reconstruction. Benefits attributed to maintenance include reduced total costs that a transportation agency incurs to deliver safe and smooth-riding roads, and re- duced vehicle operating costs and greater comfort for road users. Analyses of these
2 benefits are typically based on an empirical model relating pavement or bridge deterioration to age and cumulative usage, and principles of discounted cash flow analysis are used to compute the âlife-cycle cost,â the total net cost of providing highway service for a specified period of years that constitute a facilityâs service life. The empirical deterioration relationship, based on practical observation, has theoretical support, but researchers have not agreed on a single definitive model specification. The in- fluence of maintenance activities on pavement deterioration rates is represented differently by different analysts, and it is not well documented. Some analyses do not explicitly recog- nize the influence of routine maintenance. Pavement condition is typically characterized in terms of a âservice level.â The concept, meant to reflect physical facility characteristics that influence road-user comfort and vehicle operating costs (e.g., fuel usage and repairs) is typically measured by a single-number ser- viceability index or road rating. Several different indices are used by various agencies in the United States and abroad. Studies have shown that road usersâ perceptions of highway condi- tions, as measured by these indices, vary with the age, gender, and other demographic char- acteristics of those users. Other studies have shown that poor pavement conditions, as meas- ured by the indices, are correlated with higher vehicle operating costs. Maintenance benefits typically are estimated by forecasting higher anticipated service- level trajectories if maintenance is performed. Some agencies have concluded that total agency costs for roads on which PM is performed are lower than costs for roads that are permitted to deteriorate to levels that require repair and reconstruction. Agencies associate cost savings primarily with being able to defer reconstruction, a major capital expenditure. Agency-sponsored surveys in several states and nationally indicate that road users gener- ally have favorable opinions of highway conditions, although they are aware of deteriorated road conditions on specific routes or within particular geographic areas. Almost all state agencies responding to this studyâs survey reported that elected officials and the general pub- lic have positive opinions of agency maintenance programs. Although a number of states have adopted customer-based outlooks in their program planning and management, a major- ity of reporting agencies do not monitor public opinion about maintenance activities on a continuing basis. Only about one in five state agencies that use maintenance-oriented brief- ings or other public information instruments reported that customer opinions have had direct influence on maintenance program budgets or schedules. News media reports and some re- searchers indicate that public perceptions of maintenance are influenced by experience with traffic congestion and other conditions associated with maintenance workzones. Experiences in several states, cities, and private companies give evidence that marketing and public relations activities are used to consider maintenance issues and can enhance pub- lic awareness of highway conditions and the roles of maintenance in effective system management. However, many agencies engage in activities that are primarily of sales rather than marketing (see Table 1 on page 5 for examples). They aim to persuade taxpayers and others to support legislative initiatives or agree that the agency is doing a good job, rather than determine what characteristics of maintenance road users particularly value or dislike, and then shaping the maintenance program to enhance customer satisfaction. Marketing and public relations techniques used in other aspects of transportation management and related fields may be useful in measuring the publicâs willingness to pay for maintenance benefits and building public appreciation of those benefits.