Road safety is connected with pavement skid resistance which often triggers pavement maintenance issues. So far, many laboratory studies have been conducted trying to find a link between skid resistance and macrotexture. However, the findings cannot be extrapolated always in the field because of the multi-parametric nature of skid resistance. This triggered the present study that aims to identify key aspects of skid resistance and its main textural components, macro and microtexture. The goal is twofold: to present and assess the effect of seasonal variation on a long-term basis focusing mainly on Mediterranean climate zone and illustrate the cumulative traffic effect on skid resistance and macrotexture in the field, while paying attention to the key-role of microtexture. Study findings showed that under the effect of cumulative traffic, macrotexture and skid resistance start presenting an inverse trend. This trend seems to be related to the equilibrium phase of skid resistance performance, after which seasonal variation becomes less pronounced. In addition, the cumulative traffic in conjunction with weather variations are proved to be critical for the microtexture component. Ultimately, the study findings demonstrated the necessary awareness of constraints in using only macrotexture data to develop models for predicting field skid resistance levels.

Road surface friction, or in other words, a pavement’s skid resistance, is an essential attribute of highway safety, acting as a liaison between the infrastructure condition and the driver’s response to it through proper vehicle maneuvering. The present study reviews aspects related to the tire–road friction, including affecting factors, monitoring systems and related practices, and demonstrates the efficacy of using smart tires, or tires embedded with sensors, for the purpose of evaluating roadway friction levels in real-time while traveling. Such an approach is expected to assist drivers in adjusting their behavior (i.e., lowering their speed) in the event that signs of reduced skid resistance are observed in favor of road safety. The current challenges and research prospects are highlighted in terms of tire manufacturers’ perspectives as well as future mobility patterns with autonomous driving modes. Overall, smart tires are commented as a tool able to enhance drivers’ safety for both current and future mobility patterns, help to control pavement deterioration and complement existing practices for infrastructure condition assessment.

Pavement skid resistance is influenced by both pavement macrotexture and microtexture, with the two components providing the skid resistance properties required to assist in ensuring road safety. In addition to these factors the cumulative traffic along a pavement is a known determinant factor influencing pavement surface characteristics leading to deterioration. However, previous research efforts in this area have been evaluated based on laboratory experiments that have not proven to be easily extrapolated to represent field conditions. With this in mind, the present study aims to investigate and comprehend the long-term effect of cumulative traffic on both skid resistance and macrotexture evolution based on actual field measurements. The ultimate research goal is to develop a practical approach for analysis and interpretation of in-situ performance characteristics that could be utilized by road agencies in evaluating long-term skid resistance performance. For the investigation, an 11-year field dataset consisting of three categories of pavement sections defined by their traffic volume/characteristics and geometric design was analyzed. The analysis results showed that skid resistance and macrotexture can be separated into two defined zones during their evolution, which are determinant for the remainder of the pavement service-life. In addition, the varying characteristics of the three investigated cases were presented and a sensitivity analysis performed. Overall, knowledge gained from understanding the long-term field pavement performance can provide valuable information to road agencies for on-time pavement maintenance actions that can help ensure pavement sustainability.

One of the challenges of using recycled materials in road structures is to maintain safe and durable pavements. A multitude of research has been conducted over the years on various recycled materials, with a focus on the structural performance of pavements. Another crucial, but almost overlooked, aspect is the pavement’s ability to provide adequate skid resistance for road users under different climatic conditions. With this in mind, the present study aimed to investigate the skid resistance of asphalt mixtures containing two different types of recycled materials under laboratory-simulated weather conditions. Conventional hot-mix asphalt (HMA) and mixtures containing either reclaimed asphalt pavement (RAP) for aggregate replacement or crumb rubber (CR) as a bitumen additive were prepared and tested at different temperatures and different surface conditions (i.e., dry/wet) following a wetting protocol. Skid resistance was measured using a British Pendulum Tester (BPT). The results showed that the recycled mixtures performed similarly to conventional ones in terms of the skid resistance when the temperature was varied and under variable simulated surface conditions too. In some cases, they performed even better than conventional mixtures. Overall, a promising potential is demonstrated towards the use of the investigated recycled materials in asphalt surface courses.

The initial condition of a newly constructed pavement structure, also known as the zero point, provides valuable information and can be included in pavement management systems. The zero point data for the initial macrotexture level can be gathered both quickly and efficiently by measuring the mean profile depth (MPD) of the pavement surface with a laser profiler immediately after the end of the construction phase and before the road pavement is opened to traffic. However, in many countries the specifications for macrotexture levels during this phase are gathered through the mean texture depth (MTD) index derived from the sand patch method, which is both location specific and time-consuming. Thus, the study presented in this paper investigated the applicability of the ASTM E1845 equation to the field data collected from a newly constructed highway and then developed a methodology to form a shift factor that could allow the direct estimation of MTD data with MPD data. The investigation findings showed that the applicability of the ASTM equation was not validated for the particular highway, a conclusion that was drawn in other relevant investigations. On the contrary, the developed factor to shift MPD data to MTD appears to be effective for use by pavement engineers with validation results supporting the conclusion. This paper presents details highlighting the need to consider the individual characteristics of each pavement surface, as improper use of the ASTM equation could lead to erroneous results.