The objective of this CI contribution is to outline the growing use of global pavement surface condition (combined characteristics) indices, as compared to the use of individual unit surface condition (individual characteristics) indicators. The role of surface characteristics in pavement management systems (PMS) is described, and then the technical needs of a wide range of potential users is outlined in order to identify the potential to combine surface condition indicators into one index. On this basis, it is possible to define and develop a level of service (pavement surface performance) for road users, operators and administrators for a life-cycle performance and cost approach, and to provide recommendations on the appropriate use of pavement surface condition indicators. Functional classification, including classifications with the use of two index families (single and combined indices) and two levels per family, taking into account the complexity and the level of aggregation, are explained with typical examples giving a clear explanation of: how special indexes characterising the pavement condition permit an assessment of the effectiveness of different approaches, from technical and macroeconomic viewpoints; and how to support pavement maintenance planning goals with the use of a structural and service index rating. A comprehensive body of information about indices is not presented, but rather practical examples of the different types of indices to illustrate the concepts involved. The major problem encountered with the creation of combined indices, from an international perspective, is that the individual performance indicators used by various agencies, countries and world regions are generally not, or only to some extent, comparable (use of different factors, rating systems and measuring procedures for instance). For this reason, some harmonisation approaches are discussed in order to initiate future wider international activities to specify pavement characteristics in more uniform terms. Harmonised condition, or performance, indicators could thus be used as a more objective and effective tool in road construction and maintenance activities at various administrative levels, from local roads to international highways, including asset management. For the covering abstract see ITRD E135448.
Abstract