It sounds like an idyllic vision for the future: Cars automatically and seamlessly talking to other cars to warn about traffic ahead, bicycles wirelessly transmitting their position and speed to nearby vehicles, even construction signs beaming information about upcoming lane closures to oncoming trucks while they’re still miles away.
All these wonderful features are collectively called vehicle-to-vehicle (commonly abbreviated as V2V) and vehicle-to-everything (V2X) communications. These technologies are designed to make cars safer, more comfortable, and even more efficient. The core ideas have been tossed around for some 50 years, built on reliable technologies with worldwide deployment. V2V has even become commonplace in certain parts of the world.
Why, then, does this still sound like science fiction in America? It comes down to competing technologies, government reluctance, and an industry betting on the wrong horse.
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A History of Something—and Nothing—Happening
Perhaps the best joke in engineering is the simplest. It goes like this: The wonderful thing about standards is that there are so many to choose from! Equal parts funny and tragic, the joke gets right to the core of the problem with V2V and V2X implementations: competing standards. In fact, it’s hard to know where to even start with the history of the V2V, since the first attempts at defining standards date back to the 1970s.
It’s in 1999 when things really started to get serious, with the Federal Communications Commission (FCC) carving out 75 MHz of spectrum in the 5.9 GHz band. In the wireless world, different frequencies are used for different things—everything from traditional broadcasting to high-speed data. Allocating a band of frequencies is like carving out a piece of land for business use. This was the government throwing its weight behind a standard called Dedicated Short-Range Communications, also known as DSRC or 802.11p. That may sound like yet another flavor of the increasingly soupy alphabet that is home wireless networking, and DSRC does indeed use the same basic protocols, but this is actually quite different in concept.
The biggest difference is that DSRC is intended to be point-to-point, or peer-based. Every car, for example, would not only connect to the network to provide information but also extend the network itself. In this way, traffic would in essence become a rolling mesh, with each car acting as a repeating node. For example, the location of hazards detected by cars at the head of a pack would be beamed all along the way to those at the rear, giving those cars a chance to otherwise avoid them.
Europe embraced similar standards, and all was looking great until, well, nothing really happened. For a long time. Various vehicle manufacturers and research organizations showed concept after concept. We covered GM’s efforts in 2006. These glimpses of the bright, safe, interconnected future to come were always just that—the future. Finally, after about 15 years of standards evolving and industry groups bickering, things started to look like they were going to get real.
Until the U.S. government stomped on the brakes.
“It seemed that the industry was set to move forward with DSRC, and NHTSA got as far as an NPRM [Notice of Proposed Rulemaking] to mandate DSRC V2V in late 2016,” said Sam Abuelsamid, principal analyst for e-mobility at Guidehouse Insights. The Trump administration, however, declined to move it forward. With no mandate, auto manufacturers hesitated.
That was when another standard swooped in and stole the show.
C-V2X Changes Everything—and Wins
“At about the same time,” Abuelsamid said, “Qualcomm started pushing C-V2X as the radio standard [first riding on top of LTE and later 5G]. With the mandate stalled and automakers vacillating between DSRC and C-V2X, no one wanted to move forward with what might be the HD-DVD of V2X tech.”
Cellular V2X, or C-V2X, uses the same basic concepts as DSRC, but instead of relying on proprietary network modules that would have to be added to cars in a DSRC scenario, it instead builds upon 4G and 5G cellular networks that are already pretty much everywhere. Why invest millions to deploy something new when you can mooch off of the wireless industry’s investments?
Things stagnated again until 2020, when then-FCC Chairman Ajit Pai controversially moved to reallocate the DSRC spectrum in a plan designed to “supersize Wi-Fi.” The deed for all that digital land the FCC had set aside for V2V was changing hands. “99.9943 percent of the 274 million registered vehicles on the road in the United States still don’t have DSRC onboard units,” he said. Just like that, after decades of work, American DSRC became an also-ran.
“This battle is over, and C-V2X won hands down not only for superior performance—range, latency, capacity—but also for the business model,” Roger Lanctot said. He’s the director of automotive connected mobility at Strategy Analytics. Abuelsamid agreed: “DSRC is effectively dead in the water in North America, China has gone C-V2X, and the rest of the world will probably follow.”
With that out of the way, what can we actually expect from the technology?
A Promising Future Awaits, and Awaits …
One way or another, the basic idea is getting vehicles talking among themselves and also to the world around them, receiving real-time intel on everything from road construction to weather conditions. “For example,” Abuelsamid said, “a car driving down the road hits a patch of ice and activates ESC or the driver slams on the brakes. A basic safety message is broadcast to other vehicles or roadside units within about 1,000 meters. Those other drivers get an alert to the type of hazard.”
In this way, the V2V-enabled cars farther down the road not only can warn drivers but also reconfigure themselves, perhaps automatically enabling a low-grip stability control mode, improving safety for all. Here are some other promising ideas:
Disabled vehicles: If a car suffers a mechanical fault, it could notify other cars about its current predicament, whether that be reducing speed or coming to a stop. Following cars would alert their drivers to change lanes and slow down.
Emergency braking: If one car has to deploy an emergency auto-braking maneuver, cars following immediately behind will need to hit the brakes, as well. A wireless warning could mean the car behind automatically braking within milliseconds of the first car, far faster than a human could react.
Platooning: This is when a number of cars engage a sort of next-gen, semi-autonomous adaptive cruise control, getting into a row and driving at high speed only inches apart. This boosts both aerodynamics and speed, reducing traffic congestion and fuel consumption along the way.
And what about vehicle-to-everything, or V2X? Companies are developing podlike devices that would be mounted above an intersection, with cameras, radar, lidar, and a C-V2X radio. The pod’s sensors would always be watching, looking in all directions for approaching cars, broadcasting alerts about pedestrians or potential red-light runners.
Here are some other potential V2X implementations:
Traffic light timing: If you’ve ever encountered a stale green light on a road with a high speed limit, one that left you slamming on your brakes as it turned red at the worst possible moment, you can imagine the advantage of knowing exactly when the light ahead of you is going to change. In an autonomous future, this information could enable self-driving cars to pace themselves just right to hit only green lights, never having to waste energy speeding up and slowing down.
Lane closures and detours: Local transportation departments could deploy virtual warnings in addition to road signs, alerting cars long before they come into view about upcoming road hazards, lane closures, and even detours.
Pedestrian and cyclist detection: With integration in cellular technologies, it’d be relatively easy to integrate V2V technology into smartphones, broadcasting every cyclist’s and pedestrian’s position. Cars could start braking even before that distracted jaywalker wanders out from between parked cars.
During the decades where standards were being debated and turning increasingly stale, a few manufacturers decided to forge ahead with implementations of similar functionality on a limited basis, including a V2V feature that could warn other cars about potential road hazards based on readings from the suspension and a V2X traffic light information system that could help drivers time green lights. Both are potentially compelling features, but at this point they’re little more than proof of concept in nature given their limited implementations.
In the end, the true value of a V2V system is having every car talking to every other car. When things are segmented by manufacturer or implemented piecemeal, you’re never going to hit the kind of critical mass required to truly improve safety for the majority of drivers and pedestrians.
What About Apps?
There’s another way of getting some of this functionality in your car today, and that’s with apps like Waze. The Google-owned routing app allows any driver to report things like debris in the road or broken-down cars. Likewise, most modern navigational apps can warn about upcoming traffic congestion. These are some of the key features of V2V and V2X, implemented in a very different way.
But, as Abuelsamid said, it’s not a replacement for a dedicated solution: “There is latency in systems like Waze, and it’s inherently less reliable because it relies on users to input information, which also contributes to distraction.” Lanctot put it more bluntly: “Waze, at its best, is distracting and dangerous. “
How Do Autonomous Cars Fit In?
Much like V2V and V2X implementations, autonomous vehicles (AVs) have taken years longer to come to market than some expected. However, while a correlation seems natural, the two sets of technologies are less related than you might think.
“At its core, an AV has to be able to navigate the world based only [on] what its sensors can see,” Abuelsamid said. “There may be times when there is nothing to communicate with, just as there is for humans today. However, V2X adds an additional layer of safety and expands the situational awareness of AVs [and humans].”
Intent is an interesting problem for autonomous cars. Want to let a pedestrian know you see them? Eye contact usually works, or a wave of the hand if you want to be explicit. A self-driving car can’t do that easily; many prototype machines rely on light arrays or special chimes to tell the world around what they’re up to, but industry-wide V2X adoption would make that a whole lot easier.
Will V2V and V2X Ever Get Into Gear?
It’s been decades, and still, as former FCC Chair Pai pointed out upon reallocating the DSRC spectrum in 2020, a tiny fraction of a percent of vehicles on the road today offer anything resembling V2V and V2X. Things are still largely stagnant here in the U.S. Meanwhile, markets abroad are developing some real momentum.
“If you have any doubts as to whether C-V2X represents the future, just look to China,” Lanctot said. “There is an unmitigated embrace of the technology, which is being widely deployed.” How widely? The Buick GL8, a minivan available only in China, offers eight V2V and V2X features: emergency braking warning, control loss warning, abnormal vehicle warning, intersection collision warning, speed limit warning, signal violation warning, hazard location warning, and green light optimization speed advisory.
Keep in mind, this isn’t a vehicle offered by some hyper-progressive brand, and its technology is available today—just not here. China’s early and widespread embrace of C-V2X, plus a major push by the government, means that V2V is a reality on Chinese roads, a reality that will only become more widespread.
For those of us in America that doesn’t do us much good right now, but it will. China is the biggest automotive market in the world, and naturally, nearly every major manufacturer wants its products to appeal there. With V2V and V2X an increasingly salient selling point for cars in that market, global cars will eventually get dragged along, too.
But it’ll take some patience, leaving us with time to ponder what went wrong. Sure, it hurts a little to be playing second fiddle after so many decades of innovation and work, but that’s what happens when you bet on the wrong horse. “Europe and the U.S. are looking a little silly for having wasted so much time fighting over spectrum,” Lanctot said. It’s hard to disagree with him or the fact that V2V and V2X still hold tremendous potential—that is, if the significant hurdles to adoption can ever be overcome.