How Vehicle-to-Vehicle Communications Work

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Vehicle-to-Vehicle communications (aka V2V) is a basic building block towards automated driving. The idea is that if one in-car computer system can drive a vehicle without a human driver, several vehicles with in-car systems capable of that would be even better. Just as humans make eye contact, wave someone through, or otherwise communicate between themselves while driving, so can computers. Albeit probably with a lot less road rage.

The National Highway Traffic Safety Administration (NHTSA) defines V2V as the ability for individual vehicles on the roadway to communicate with one another for safety purposes. Vehicles exchanging information, even if not autonomously driving, can help alleviate crashes, traffic congestion, and more if they are “talking.”

The technology behind this involves both position sensing and communications wavelengths to allow V2V to happen. The position sensing would include coordinates and movement rate (speed) as well as relative information such as where stops or traffic controls are located as the vehicle approaches them. The latter can be handled either via GPS mapping or vehicle-to-infrastructure (V2I) communications.

This information can be used to communicate things like potential collision paths, dangers obscured by weather or traffic, changes in terrain, etc. The information could solve a wide variety of problems such as congestion at choke points where vehicles are forced into lane changes (construction zones, roadway narrowing, and the like), accidents involving inclement weather, accidents from out-of-control vehicles, roadway safety issues from broken down vehicles or emergency response personnel/vehicles, and more.

The current NHTSA guidelines for V2V communications ask for a message range of at least 300 meters, the ability to communicate omni-directionally (meaning in all directions), and to process at least 10 ten messages per second. These are lightweight goals, given today’s computing and wireless broadcast capabilities, but provide a starting point for these systems. These standardized rules were published by the NHTSA in 2017 and opened for commentary from the public. Those comments resulted in several more proposals on network spectrums, message parsing, and more for both V2V and V2I systems.

Most current V2V communications are taking place on 4G and 5G networks with relatively limited broadcast zones in a wireless mesh to prevent too much overlap. Auto manufacturers are working with the NHTSA towards standardization for these communications. Test systems are being deployed around the U.S. and Canada.

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