This synthesis report will be of interest to pavement design, construction, management, and research engineers, highway safety officials, and others concerned with pavement friction characteristics. It describes the current state of the practice and discusses the methods used for evaluating wet pavement friction characteristics of new and restored pavements. This synthesis reviews models used for measuring and evaluating friction and texture, causes for friction changes over time, and aggregate and mix design to provide adequate friction. Also presented are construction and surface restoration practices for providing good pavement surface characteristics. In addition, considerations of noise and ride quality are discussed when compromise may be required.

Real-time measurement of the tire-road friction coefficient is extremely valuable for road-maintenance operations and highway safety management. This paper presents a systematic framework to predict skid resistance of wet pavement with a non-contact method, which could be a potential approach for real-time measurements of pavement friction. The grip potential of pavement is estimated according to the measured pavement texture based on theoretical simulation of the complete hysteresis and partial adhesive effects during tire sliding on wet pavement. Such a method could be potentially used for the purpose of harmonization analysis of skid resistance and potential capability of optimization of pavement surface texture.

This report contains guidelines and recommendations for managing and designing for friction on highway pavements. The contents of this report will be of interest to highway materials, construction, pavement management, safety, design, and research engineers, as well as others concerned with the friction and related surface characteristics of highway pavements.

The overall objectives of this research study may be stated as follows: Determine if surface characteristic measurements can be correlated to wet-pavement crashes in Ohio; Provide improved guidance on the use of ribbed versus smooth tires for pavement surface friction testing in Ohio, including the identification of suggested minimum surface friction numbers associated with each tire type; Provide recommended desirable or target surface friction numbers as a function of site categories and friction demand. Accomplishments of these objectives will help ODOT address their goal of reducing total crashes 10 percent and rear-end crashes by 25 percent by 2015.

This work presents the results of RILEM TC 237-SIB (Testing and characterization of sustainable innovative bituminous materials and systems). The papers have been selected for publication after a rigorous peer review process and will be an invaluable source to outline and clarify the main directions of present and future research and standardization for bituminous materials and pavements. The following topics are covered: - Characterization of binder-aggregate interaction - Innovative testing of bituminous binders, additives and modifiers - Durability and aging of asphalt pavements - Mixture design and compaction analysis - Environmentally sustainable materials and technologies - Advances in laboratory characterization of bituminous materials - Modeling of road materials and pavement performance prediction - Field measurement and in-situ characterization - Innovative materials for reinforcement and interlayer systems - Cracking and damage characterization of asphalt pavements - Recycling and re-use in road pavements This is the proceedings of the RILEM SIB2015 Symposium (Ancona, Italy, October 7-9, 2015).