The Evolution And Impact Of V2X Communication

By John Oncea, Editor

V2X communication leverages DSRC and 5G C-V2X RF technologies, enabling real-time data exchange between vehicles, infrastructure, and users while advancing safety and traffic efficiency.
Back in May 1969, Hot Rod was writing about The Joker, Handles & Cranks, and Action at the Front. On page 103 of the issue, General Motors ran an ad proclaiming, “Someday roads will tell cards where to go.
“And you’ll be able to drive cross-country without a road map and never get lost. Just leave the guiding to ERGS: The Electronic Route Guidance system developed cooperatively by General Motors Research Laboratories and the Corporation’s Delco Radio Division.”
The technology behind ERGS was … simple?
The driver would enter a destination code on a special radio receiver panel and begin driving. Antennas buried in the pavement would let a roadside computer know where the driver was going and, “Quicker than a blink, the computer processes your destination information, signals back to your radio receiver, and the proper directions light up on your receiver panel.”
ERGS was part of a broader intelligent transportation system, an advanced application that aims to provide services relating to traffic management and enable users to be better informed and make safer, more coordinated, and smarter use of transport networks.
While the ERGS program was ultimately discontinued in 1970 due to high infrastructure costs and technological limitations of the time, its foundational concepts – real-time route guidance and electronic driver communication – directly inspired the development of modern vehicle navigation systems, according to Online Pubs.
Today’s systems, such as GPS-based navigation, smartphone apps (Google Maps, Apple Maps, Waze), and in-car navigation units, provide dynamic, real-time routing, voice guidance, and individualized communication that achieve and far exceed the original ERGS objectives.
ERGS also laid the groundwork for Vehicle-to-Everything (V2X) Communication, a change in thinking in transportation, equipping vehicles with the ability to exchange real-time data with other vehicles, infrastructure, and vulnerable road users, dramatically improving safety, efficiency, and mobility across networks.
Defining V2X: RF Technologies And Core Architecture
V2X describes communication systems whereby vehicles exchange information with other vehicles (V2V), infrastructure (V2I), pedestrians or vulnerable road users (V2P), and with network/cloud services (V2N). The two primary RF technologies underpinning V2X are DSRC (Dedicated Short-Range Communications, based on IEEE 802.11p) and C-V2X (Cellular V2X). C-V2X operates over LTE/5G and increasingly utilizes direct sidelink (device-to-device) channels within the upper 30 MHz of the 5.9 GHz ITS band – a regime established by the FCC’s 2024 Second Report & Order.
C-V2X supports two complementary modes: in direct (sidelink) mode, devices communicate peer to peer without cellular infrastructure; in network (Uu) mode, traffic uses the operator’s cellular network, which is suitable for non-latency-critical messaging or broader connectivity beyond immediate range.
In real deployment, vehicles include On-Board Units (OBUs), and intersections or roadside points host Roadside Units (RSUs). These units exchange standardized messages (e.g., speed, position, hazard warnings) across OEMs and infrastructure providers. Interoperability is a central goal, driving efforts in standardization and spectrum governance. Utah DOT’s snowplow program, for instance, integrates V2X for signal preemption and improved intersection safety.
The Evolution Of V2X: From DSRC To Cellular Architectures
In earlier V2X efforts, DSRC (based on IEEE 802.11p) was favored due to its low-latency, local communication model. Over time, however, industry momentum shifted toward cellular alternatives.
In 2020, the FCC issued a Report & Order that repurposed the lower 45 MHz (5.850–5.895 GHz) for unlicensed uses and retained the upper 30 MHz (5.895–5.925 GHz) for ITS operations. In that same order, the FCC required existing ITS licensees to vacate the lower 45 MHz by July 2022 and transition to the upper portion, and it foreshadowed a shift from DSRC to C-V2X in future operations.
The FCC’s 2024 Second Report & Order further codifies the rules by which C-V2X operates in the upper 30 MHz, sets emission limits, channelization rules, and defines a transition path for phasing out DSRC. That new ruling establishes that new ITS deployments under the updated regime must use C-V2X rather than DSRC within that allocated band, according to Venable.
At the same time, state and local agencies, in collaboration with OEMs and infrastructure vendors, are moving from pilot projects to operational deployments. One notable case: between 2020 and 2022, Indiana DOT deployed V2X-equipped queue warning trucks to signal trailing vehicles about stopped traffic. Some evaluations attributed up to an 80 % reduction in hard braking incidents in test corridors. The low latencies and increased reliability of C-V2X under real RF conditions make such outcomes plausible.
The maturation of 5G, enhancements in sidelink protocols, growing consensus on interoperability, and broader cellular coverage are enabling more advanced use cases – cooperative adaptive cruise control, enhanced pedestrian systems, and cross-OEM coordination.
In August 2024, USDOT published “Saving Lives with Connectivity: A Plan to Accelerate V2X Deployment,” a national roadmap to guide coordinated deployment of interoperable V2X systems across infrastructure and vehicle ecosystems. The plan sets goals, roles, funding mechanisms, and strategies to align deployment across the public and private sectors.
Current Landscape: Waivers, Pilots, And Deployment Challenges
In the interim period while new rules take effect, many U.S. V2X deployments operate under waiver authority. The FCC posts public notices where manufacturers, state DOTs, or joint waiver parties request permission to deploy C-V2X equipment in the upper 30 MHz ahead of full regulatory compliance. One such waiver submission outlined technical parameters to protect incumbent operations while permitting initial deployment of C-V2X in the 5.905–5.925 GHz band.
Many DOTs and municipalities – Utah, Indiana, and New York City among them – have reported operational gains from pilot V2X installations: fewer collisions or near misses, better flow, and pedestrian safety benefits. Utah, in particular, is scaling its snowplow + intersection V2X program to expand signal preemption and integration under adverse weather.
However, deployment faces significant headwinds. Regulatory clarity is still evolving: while the 2024 FCC order is a landmark, residual questions remain around interoperability, channel sharing, certification, and sunset timelines for DSRC. OEMs tend to adopt cautiously, awaiting stable standards and certification regimes before mass integration in new vehicles. Infrastructure costs – fiber backhaul, power, maintenance, RSU deployment – remain nontrivial.
Ensuring seamless interoperability across devices from different manufacturers under varied RF conditions is also a major technical challenge. Despite these obstacles, many agencies are forging ahead with phased upgrades, particularly at high-risk intersections and corridors where safety ROI is clear.
Vision Forward: 5G+, AI, And Global Coverage
The industry’s trajectory clearly points toward 5G sidelink (5G-V2X) as the next stage, with higher throughput, lower latency, and more flexible spectrum use. Roadmaps anticipate broader 5G-V2X deployment in the mid to late 2020s, beginning in Europe and converging globally as OEMs embed new radios and align protocols. The future V2X architecture will blend direct sidelink, cellular network mode, edge/cloud compute, and potentially non-terrestrial networks (LEO satellites, high-altitude platforms) to extend reach in remote or underserved areas.
Machine learning and AI will play central roles: real-time network slicing, predictive traffic modeling, digital twins of road networks, adaptive channel allocation, and latency optimization. V2X systems will need to meet ultra-reliable low-latency communications (URLLC) and massive machine-type communications (mMTC) requirements, particularly in cooperative and autonomous driving contexts where sub-millisecond response is critical.
Security, privacy, and trust infrastructure are foundational. A commonly studied architecture is the Security Credential Management System (SCMS), which issues pseudonym certificates to vehicles and infrastructure nodes, enabling authenticated messaging while maintaining user privacy. Standards bodies (SAE, IEEE, 3GPP) and industry consortia continue to refine certificate management, misbehavior detection, revocation strategies, and resilient trust models. As V2X networks expand, they will integrate with smart city systems, energy grids, and multimodal transport platforms, demanding architectures resilient to cyberattack, interference, and system faults.
V2X communication is evolving from DSRC-based pilots toward a more robust, standards-driven infrastructure anchored on C-V2X and ultimately 5G-enabled sidelink technologies. The 2024 FCC Second Report & Order and USDOT’s national deployment plan, Saving Lives with Connectivity, are key regulatory and strategic milestones providing clearer paths for DSRC sunset, spectrum allocation, interoperability, and deployment sequencing
While challenges remain – regulatory fine-tuning, infrastructure cost, interoperability, OEM risk – many agencies are already delivering safety gains via pilot V2X systems. Over the coming decade, the synergy of 5G sidelink, edge/AI optimizations, and robust security models may transform V2X from experimental testbeds to essential infrastructure undergirding safer, smarter, and more efficient mobility networks.