With the advancement of digital technologies, the creation of a digital twin of the road has moved from a theoretical concept to a tangible reality. Digital twins enable rapid simulations and robust data management, thereby ostensibly empowering policymakers and engineers to make expeditious and well-informed decisions. This paper examines the potential applications, benefits, and implications of deploying the digital twin of a road, a real-time virtual replica of physical road infrastructure, from four critical perspectives: physical modelling and numerical simulations, data management, law, and sustainability assessment. This paper explores the potential of digital twins to offer advancements in the efficiency and sustainability of road infrastructure. By enabling comprehensive monitoring and optimisation, the digital twin of a road facilitates applications in sustainable design, predictive maintenance, and efficient operation. Real-time data collection and analysis could allow for proactive maintenance and better resource management, while the integration of advanced materials and sensor technologies can enhance road durability and performance. Additionally, the digital twin of a road could support a holistic life cycle approach, facilitating better decision-making and planning for future infrastructure projects, with the potential to contribute to smarter and more sustainable transportation networks. The implementation of digital twins of roads, however, faces several challenges and raises numerous concerns. Key issues include the integration of diverse data sources, ensuring data accuracy and reliability, and addressing data protection and security concerns, requiring robust legal and regulatory frameworks to manage and protect personal data.