Vehicle-to-everything

Vehicle-to-everything (V2X) communication is the passing of information from a vehicle to any entity that may affect the vehicle, and vice versa. It is a vehicular communication system that incorporates other more specific types of communication as V2I (Vehicle-to-Infrastructure), V2V (Vehicle-to-vehicle), V2P (Vehicle-to-Pedestrian), V2D (Vehicle-to-device) and V2G (Vehicle-to-grid).

The main push for V2X is safety, with energy savings also being important. However, there are still obstacles preventing the roll-out of this technology, mainly legal issues and the fact that, unless almost the totality of the existing vehicles adopt it, its effectiveness is rather limited. British weekly "The Economist" even argues autonomous driving is more regulatory than technology driven.

V2X communication is based on WLAN technology and works directly between vehicles or the infrastructure, which form a vehicular ad-hoc network, as two V2X senders come within each other’s range. Hence it does not require any infrastructure for vehicles to communicate, which is key to assure safety in remote or little developed areas. It is particularly well-suited for V2X communication, due to its low latency and the ability to communicate instantly. It transmits messages known as Common Awareness Messages (CAM) and Decentralised Notification Messages (DENM) or Basic Safety Message (BSM). The data volume of these messages is very low. The radio technology is standardised as part of the WLAN IEEE 802.11 family of standards and known in the US as WAVE (Wireless Access in Vehicular Environments) and in Europe as ITS-G5.

Through its instant communication V2X allows road safety applications such as (non-exhaustive list):

The US National Highway Traffic Safety Administration’s (NHTSA) report “Vehicle-to-Vehicle Communications: Readiness of V2V Technology for Application“ lists the initial use cases envisioned for the US. European standardisation body ETSI and SAE published standards on what they see as use cases. Early use cases focus on road safety and efficiency.

In the medium term V2X is perceived as a key enabler for autonomous driving, assuming it would be allowed to intervene into the actual driving. In that case vehicles would be able to join platoons, the way HGVs do.

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Wikipedia