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Self-Driving Cars: What Is V2X Technology?

In a glossary of terms for self-driving cars, V2X technology would be defined as the technology allowing communication among all traffic-related elements. It will play a key role in the hive of autonomous vehicles (AV) being able to safely and efficiently operate.

Several players developing AVs claim they will have Level 4 AVs ready for production within the next five years. The Society of Automotive Engineers and the National Highway Traffic Safety Administration defines Level 4 automation as fully self driving under certain conditions. Under these conditions, such as some urban ride-sharing scenarios, the vehicle can operate on its own with the driver only providing the destination. A human driver will be necessary to assume control outside of the ideal condition zones.

Level 5 is the point that self-driving is possible under all conditions and in all locations. That is, the AV can operate without a driver or occupants of any type virtually anywhere. Although some AV developers are convinced they will have Level 4 self-driving cars in the near future, there are a number of big hurdles between Level 4 and Level 5. These include regulations, insurance issues, comprehensive street mapping and more.

Also required to get from Level 4 to Level 5 — and the key reason many experts argue that if Level 5 is even achievable — is the ability of AVs to communicate with one another with vehicle-to-vehicle (V2V) communication, as well as with traffic infrastructure through vehicle-to-infrastructure (V2I). Lumped together, V2V and V2I comprise vehicle-to-everything (V2X).


Two well-publicized accidents involving vehicles operating with some degree of autonomous technology illustrate the potential benefits of V2V technology. Both the fatal accident caused by a semi tractor-trailer turning in front of a Tesla operating on its AutoPilot program in Florida, and the non-injury accident of an Uber test Volvo AV that failed to detect a human-driven vehicle that suddenly turned in front of it in Arizona. Both probably could have been avoided had the vehicles been communicating with one another.

To date, most accidents involving AVs operating in autonomous mode have involved a human-driven car rear-ending the AV stopping at an intersection where the light just went from green to yellow. Whether the accident was caused by an AV’s sensors failing to detect a vehicle turning across its path or a human driver not expecting the AV to suddenly stop in response to a changing traffic light, V2V communication probably would have prevented the incidents entirely.

AVs with V2V technology will not only broadcast their current position to surrounding traffic, but will also alert traffic to upcoming maneuvers, such as left-hand turns. Such communication will also alert nearby traffic to traffic jams, accidents and road construction, affording those AVs the opportunity to set a new course to their destination.


An appropriate illustration of V2I technology is Audi’s Traffic Light Information (TLI). Recently launched in the pilot city of Las Vegas, TLI is a slick bit of 4G LTE technology that, in properly equipped Audi models, provides a countdown until the next traffic light turns from red to green. In cars driven by humans, TLI reduces anxiety when stopped at a traffic light, as well as allows drivers to adjust their speed when approaching a red light to avoid coming to a complete stop.

In its current application, this V2I technology is just sort of interesting, but it sets the stage for all manner of time and fuel saving uses. For instance, it eventually could plan routes based on the rate of traffic light change, or send traffic light information directly to your AV’s acceleration and braking guidance systems.


Both core V2X technologies have their own issues slowing down full implementation. In the case of V2V, it requires all motorized vehicles to be equipped to be totally effective. That means not only must all the various AV makers use exactly the same communication technology, but every motorized vehicle on the road must have it. It will be decades before it’s possible for every vehicle to be an AV with V2V capability.

We constantly hear about the sad shape of the infrastructure in this country. Governments are struggling to update roadways and bridges. From where will the investment come to create the grid of V2I communications AVs will require?

What it means to you: V2X is essential for hundreds of thousands of self-driving cars to safely operate.

Russ Heaps
Russ Heaps
Russ Heaps is an author specializing in automotive, financial and travel news. For nearly 35 years he has covered the automotive industry for newspapers, magazines and internet websites. His resume includes The Palm Beach Post, Miami Herald, The Washington Times and numerous other daily newspapers through syndication. He edited Auto World magazine, and helped create and edit NOPI Street... Read More about Russ Heaps

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