Mainstream media outlets heavily touted vehicle-to-vehicle/-infrastructure (referred to as V2X) communications after a recent NHTSA endorsement. Often overlooked are technical challenges that still must be overcome before V2X can make any real impact.

The U.S. NHTSA (National Highway Traffic Safety Administration) hasn’t set any timetable for determining whether or not it will make OEMs put V2X on vehicles. Security is one of the technical hurdles that’s slowing decisions about deployment. Getting enough vehicles on the road to bring any real benefit is another roadblock. There’s also a challenge from the cloud.

Most OEMs and Tier 1s are viewing it as a long-term technology. As they move towards autonomous driving, many developers see V2X as "another sensor" that can help control systems understand what’s going on at distances greater than onboard sensors can provide. It can also alert controllers that an unseen car in front of a large truck has slammed on its brakes. However, the combination of V2X with any form of autonomy won’t happen soon.

“Do we need V2X for autonomous driving? No,” said Kay Stepper, Regional Business Manager for Automated Driving at Robert Bosch Chassis Systems Control Division. “Will it help? Yes. Once V2X is in place, of course we’ll utilize it. But deployment will take a long time.”

While government agencies grapple with the timing of a rollout, companies continue to explore the benefits of using cellular links to collect data that loosely mimics the capabilities of the dedicated short range communications (DSRC) used for V2X.

“V2X is another sensor, but I believe there’s more information available in cellular, 3G, and 4G than you can get with DSRC,” said Erik Coelingh, Senior Technical Leader at Volvo Cars. “If there’s a detour or lane closure, GPS won’t help. You need to go to the cloud to a real-time network.”

Others contend that cellular links may be an interim technology that will eventually share a role with DSRC.

“One stepping stone for V2X is the introduction of vehicle-to-cloud data communication and the anonymous aggregation of this data in the cloud,” said Tejas Desai, Head of Interior Electronic Solutions at Continental Automotive North America. “This will allow for the systems to be built up over time instead of requiring full infrastructure to be in place before realizing benefits to safety or realizing any of the autonomous functionality.”

The transition to a full infrastructure is a major hurdle for V2X. Until a solid percentage of vehicles offer DSRC connectivity, it’s difficult to justify the cost of installing transceivers. Many observers feel the technology will languish unless regulators take a stand.

“Without a government mandate, V2X won’t happen,” said Andy Gryc, Senior Automotive Product Marketing Manager for QNX Software Systems. “Who will spend the money to put the technology into vehicles if they can only talk to your fleet?”

Paolo Ruffino, ADAS Marketing Manager at STMicroelectronics, echoed concerns about investing in a V2X rollout. “The main threat to this technology is the lack of a business model that could lure the infrastructure owners, such as telecom, and to some extent road, operators,” he said.

Security is another concern that’s slowing development. Before cars can used V2X input for safety-related actions, controllers must know that communications came from a real car or roadside beacon, not a hacker.

“Security on V2V is critical,” said Alois Seewald, Global R&D Director and head of TRW’s Safety Integration Team. “If you’re going to use it for safety information, you need to know you’re getting good data.”

Some observers feel that security can be improved after the first rollout of V2X systems, particularly if the inputs aren’t used for automated safety actions such as braking. Early systems will only be used to warn drivers, who can better determine whether they’re getting false alarms. But if V2X becomes part of active safety systems, it will have to have very solid security technologies that can be upgraded as threats change.

“Once V2X is integrated as another sensor into vehicle control systems, security will be even more important,” said Brian Daugherty, Visteon’s Associate Director of Advanced Development and Intellectual Property. “The ability to handle future upgrades will be a key deployment feature; you don’t want the early systems to become obsolete due to security protocol modifications.”

Aftermarkets are yet another issue that divides developers. Some view aftermarket systems as a viable way to speed up deployment and increase the volume and value of these communications. Others don’t feel that independent suppliers can play a role in safety-related technologies.

“Aftermarket systems will dramatically increase the V2X penetration curve and bring a corresponding increase in the value of the entire ecosystem to drivers,” Daugherty said. “Aftermarket systems will need to bring value to the purchaser and could range from ‘here-I-am systems’ with no feedback to full V2X systems with a display and a suite of warning algorithms.”

Others contend that aftermarket systems may be used only for basic communications. Automakers aren’t likely to let unauthorized boxes connect to in-vehicle networks that can impact safety.

“OEMs have strong reservations about letting an unknown entity have access to the safety system,” Seewald said. “OEMs may provide products for the aftermarket, but it’s unlikely that they will accept a true aftermarket system. Another issue for aftermarket suppliers is the difficulty of providing redundancy.”

While the industry and regulators grapple with these and other issues, observers note that it may be important to start using the 5.9-GHz bandwidth set aside for V2X. The U.S. FCC (Federal Communications Commission) is examining the impact of letting non-automotive groups share this currently unused spectrum. That could impact the ability to communicate in real time, which is critical for safety applications.

“There is a strong desire from other industries to share the 5.9-GHz spectrum that has been reserved exclusively for V2X,” Daugherty said. “If action isn’t taken quickly, spectrum sharing may lead to degraded V2X performance.”