Smart roads: A state of the art of highways innovations in the Smart Age

The years we are experiencing are often identified as those of the Age of Smart Technologies. Smart is now a very popular term, with the meaning of clever, intelligent, sharp, quick on the uptake. Its extensive meaning can be grasped if we consider it as an acronym for Self-Monitoring Analysis and Reporting Technology to indicate the essential features of the innovative technologies that characterize today's society in its daily life. Thus, the advent of the Smart Age, which is therefore the era of smart technologies, has heavily characterized and modified many aspects of today's society compared to the past. In this panorama, some arising questions regard transport infrastructure systems and, first of all, road transport. This research proposes a focus on one main issue: how roads fit into this smart revolution? Actually, the paper aims to offer an overview of the smart approach in road engineering by proposing a broad discussion about the current state of innovation in the smart roads field, i.e. the roads of the Smart Age. After defining the key functions of a smart road, the paper reviews some innovative technologies that make these items effective. These are studied in depth both with regard to motorway-type infrastructures and urban roads and intersections, with attention to the various technological aspects and to the benefits perceivable by management, users and the community. The paper, therefore, offers a bird's eye view of this extremely dynamic sector with innovative technologies for a new intelligent and connected mobility, and discusses some of their criticalities and strengths allowing for optimization and development of new transport functions and services, improving energy efficiency and promoting social, economic and environmental sustainability. (C) 2021 "Authors". The Published by Elsevier B.V.