Public Benefits of Highway System Preservation and Maintenance (2004)

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26 CHAPTER FIVE CONCLUSIONS This synthesis report provides an assessment of the state of practice regarding the estimation and communication of the public benefits of highway maintenance. This assess- ment was derived from a literature review, a formal survey of highway agency practices, and discussions with profes- sionals in several fields, and is summarized in the follow- ing conclusions. • Benefits of maintenance—A wide range of public benefits have been postulated and analyzed in the lit- erature. The literature presents limited empirical evi- dence to support claims that the net public benefits of preventive maintenance (PM) and preservation are positive. Research indicates that the perceived value of a smooth ride varies substantially among subsets of road users. Research supports the correlation be- tween poor pavement condition and high vehicle op- erating costs. Little evidence was found that road us- ers—other than commercial truckers—or other stakeholders perceive this correlation to be signifi- cant. Some private-sector companies have tied com- pany profitability and management incentives to maintenance performance. • Service conditions influenced by maintenance— Many highway professionals accept the concepts that (1) single-number indices may be constructed to characterize the overall condition of pavements and bridges and (2) declines in these indices (e.g., over time and with traffic) are indicators of reductions in the net public benefits produced by roads. These concepts are embodied in an empirical model, termed in this syn- thesis the “standard model,” which relates service dete- rioration to age or facility usage. This standard model is the foundation of most analyses of the public bene- fits of maintenance. At this time however – No single index has yet gained universal accep- tance for use by all U.S. agencies and researchers. – Comparisons of the results of studies about user benefits based on different indices consequently are often difficult. – Research indicates that road users’ appreciation of factors reflected in pavement condition indices may vary substantially with age, gender, trip pur- pose, and other road-user characteristics. – Research indicates that road users perceive main- tenance-induced travel delay to be associated with waiting time, speed reductions, and detours; how- ever, these delays are typically not included in the analyses of maintenance benefits. • Analysis of maintenance benefits—The empirical model relating pavement condition to cumulative ef- fects of traffic loads and materials aging is generally accepted by highway professionals and used as a ba- sis for estimating the benefits of maintenance strate- gies. Analyses showing the positive net public benefits of PM or preservation rely generally on principles of discounted cash-flow theory embodied in a life-cycle cost analysis that compares diverse benefits and costs incurred at different times during the service life of a facility. At this time however – No single precise specification of the empirical condition deterioration model has been generally accepted and applied in such analyses. – Assumptions made regarding the relationship of the empirical model’s functional characteristics (e.g., slope and functional form) to the comple- tion of periodic, routine maintenance vary among research studies. – Life-cycle cost analyses of maintenance benefits typically include benefits for and costs to road us- ers and the road agency, and sometimes those analyses include items for which monetary values must be inferred. – Little evidence was found to confirm that road users and other stakeholders prefer or attribute greater value to efficient highway maintenance strategies, that is, to those with lower total life- cycle cost. • Definitions of what maintenance is—There is little consistency among practitioners and researchers re- garding definitions and distinctions among various maintenance activities. Also, various analyses of benefits are not necessarily comparable. In particular – Frequently used terms for categorizing mainte- nance actions are defined differently by various authorities. – Various maintenance actions may be placed into different categories or classes by various authori- ties, even within a seemingly common set of cate- gories. – Definitions of “preventive maintenance” and “preservation” have been published by AASHTO committees, but are not necessarily used consis- tently by all practitioners. • Consideration of maintenance benefits in agency de- cision making—Current practices concerning the benefits of PM and preservation vary among state highway agencies. Although the theoretical benefits

27 of maintenance are embedded in the pavement and bridge management software used by most state highway agencies, those management tools are used for the most part only as required by federal regula- tion. Consequently – Only one-third of these agencies reported the use of life-cycle costing or other benefit–cost meth- ods to assess maintenance priorities; two-thirds of these agencies use such methods only for major projects. – Only one-third of these agencies directly compare maintenance and new construction in their budg- eting process; of these, two-thirds do so only for major maintenance projects. • Marketing of maintenance—Some agencies have used sales, marketing, and public relations tools to inform elected officials and road users generally about the net benefits of maintenance, and to per- suade voters to approve legislative initiatives to in- crease funding for maintenance and rehabilitation. Some agencies cite anecdotal evidence that market- ing or public relations efforts build support for main- tenance programs. Such evidence includes favorable legislative outcomes, favorable media coverage, and reductions in numbers of complaints received, fol- lowing the publication of brochures, conducting of legislative briefings, and other specific actions. Ex- perience in other areas of transportation management and other fields suggests that marketing and public relations techniques could be used to raise public awareness of maintenance benefits and to develop es- timates of the value that people place on smooth roads and other service characteristics that mainte- nance can influence. This study found little evidence that marketing techniques that have been applied to define PM and preservation programs that road users and other stakeholders appreciate yield public bene- fits.