The long-running saga of V2X (vehicle to everything), a system that uses part of the wireless spectrum to allow vehicles to communicate with our road infrastructure and each other, appears to finally be over. On Friday, the US Court of Appeals for the District of Columbia ruled that the Federal Communications Commission can go through with its plan to free up part of the spectrum previously set aside for vehicles and infrastructure to talk to each other. Instead, that bandwidth will be turned over to Wi-Fi instead.
The FCC set aside the 5.9 GHz band for V2X back in 1999. A communications protocol that vehicles could use to alert each other to dangers sounded like a great idea at the time, and the plan was to use dedicated short-range radio communication (DSRC) wireless to power the system.
Originally, the technology was meant to be fitted just to vehicles, but engineers got ambitious and decided that instead of just V2V, vehicles should be able to talk to things like traffic lights as well. This would lead us to a traffic utopia, where congestion and crashes are things of the past. There was even thought given to making pedestrians dependent on DSRC to avoid being flattened by speeding cars.
But as you might have noticed, your car almost certainly doesn’t have a DSRC modem more than 20 years after the industry decided to adopt the technology. In 2016, the National Highway Traffic Safety Administration published a Notice of Proposed Rulemaking that would have seen DSRC-based V2X become mandatory on all new cars and trucks in the US. But the closest thing on the roads is Audi’s traffic light assist, and that uses 4G LTE, not DSRC. (And three years into the pandemic, the tech is next to useless in Washington, DC, as none of the light timings match what the cars think will happen now.)
Get real—DSRC is never going to happen
A technology like V2X only works if a substantial percentage of the vehicles on the road make use of it. But the continuing failure of automakers to actually build DSRC into their cars means there is no installed user base to benefit from the technology, even after two decades.
That ongoing failure has been evident to the FCC for many years. In 2020, the agency finally decided to reallocate 45 MHz from 5.850 to 5.9252 GHz. This bandwidth would be taken away from automakers and highway planners and given to Wi-Fi, which has actual users who need bandwidth.
A pair of industry trade groups, the Intelligent Transportation Society of America and the American Association of State Highway and Transportation Officials, took the FCC to court to prevent the reallocation, but as of last week, that legal challenge is over.