On the performance of inter user coordination for resource allocation enhancement in NR V2X mode 2 -- Operational deployment of GNSS anti-spoofing system for road vehicles -- Deployment and simulation of a real ITS-G5 implementation -- Towards an Adaptive Blockchain for Internet of Vehicles -- Traffic Light Priority in NordicWay -- Radio resource management in next-generation railway system with heterogeneous multi-hop relaying -- Train-to-Train Connectivity for Safety-Critical Use Cases -- 5G Technology for Next-Generation Wireless Consist Networks in Railways -- Wide Band Critical Communications for High Dynamic Vehicles -- Autonomous Vehicles: Communication and Cooperation -- Towards 6G: Paradigm of Realistic Terahertz Channel Modeling.

This book constitutes the refereed proceedings of the 16th International Workshop on Communication Technologies for Vehicles, Nets4Cars/Nets4Trains/Nets4Aircraft 2021, held in Madrid, Spain, in November 2021. The 6 full and 2 short papers were carefully reviewed and selected from numerous submissions. The selected papers present original research results in areas related to the physical layer, communication protocols and standards, mobility and traffic models, experimental and field operational testing, and performance analysis.