Incorporating 3D printing and machine learning to revolutionize transportation infrastructure: Building tomorrow

Abstract. In recent years, three-dimensional (3D) printing and machine learning (ML) have evolved in various industries, including but not limited to architecture, construction, and buildings. 3D printing, also known as additive manufacturing (AM), is a tool used for creating three-dimensional structures by layering materials using digital designs through machine learning based on pre-identified parameters and the desired output. However, AM is still relatively unexplored in infrastructure projects. By using AM's new capabilities, researchers have gained unprecedented access to new design possibilities and operational flexibility. However, applications related to transportation infrastructure have not mirrored this revolutionary improvement. Thus, this article provides a comprehensive review of AM innovations and their abilities in transportation infrastructure as a potential future reference to support the Ministry of Transport (MoT) and other agencies continuous rehabilitation of tunnels, bridges, and transportation structures through more efficient techniques. In conclusion, by integrating 3D printing and ML into transportation infrastructure, it is feasible to create intelligent (smart) systems that adapt to changing conditions in real time, enhancing overall efficiency and mitigating traffic congestion. In the future, it is expected to change the current transportation infrastructure to a fully intelligent transportation system, and this goal is in line with the Sustainable Development Goals (SDGs).