v2x

V2X, or vehicle-to-everything communications, refers to wireless technologies that enable data exchange between vehicles and other road users and infrastructure. Its aims are to enhance safety, traffic efficiency, and mobility by sharing information such as position, speed, heading, and road conditions in near real time. Core communication modes include vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), vehicle-to-pedestrian (V2P), and vehicle-to-network (V2N).

Two main technology families are used for V2X. DSRC, implemented as IEEE 802.11p/WAVE and widely used in North America, relies on short-range, low-latency communications and standardized message sets such as Basic Safety Messages and, in Europe, Cooperative Awareness Messages. Cellular V2X (C-V2X) uses 3GPP cellular technology over PC5 for direct vehicle communications and Uu for networked communication, with NR-V2X evolving in 5G. Standards organizations differ by region, with SAE and IEEE/ITS-G5 in some areas and ETSI ITS-G5/CITS in Europe, but both converge on similar data primitives and security concepts. Message sets include CAM (Cooperative Awareness Message), DENM (Decentralized Environmental Notification Message), BSM (Basic Safety Message), and, for intersections, SPaT (Signal Phase and Timing) and MAP, which provide traffic signal and map information.

Applications span safety assistance, such as collision avoidance and vulnerable road-user protection, to traffic management, dynamic routing, and fleet logistics. System architecture typically includes onboard units in vehicles, roadside units, back-end clouds, and network operators, sharing data through standardized interfaces and message formats. Deployment remains in pilot or limited commercial phases in many regions, with adoption influenced by spectrum policy, interoperability, latency and reliability requirements, and cybersecurity and privacy protections.