Road operators are working to make smart road systems a reality by embracing digital-era technologies such as vehicle to network to everything (V2N2X), autonomous vehicles (AVs) and AI-assisted Intelligent Transportation Systems (ITS). These technologies promise to help them revolutionize the travel experience and ensure safe, on-time, connected and sustainable journeys for all highway users. To turn this promise into reality, operators need to make sure their mission-critical IP/MPLS wide area networks (WANs) can keep pace with the connectivity demands of physical and digital highway infrastructure and counter more complex cyber threats. This paper explains how new WAN capabilities and innovative use cases such as segment routing, operational technology (OT) cloud networking, networking for AI workloads, and zero-trust quantum-safe networking can help road operators use their WANs to unlock the full potential of smart roads.