The EU does not mandate a single V2X radio
Most tenders for connected roadside infrastructure reach the same question within a page or two: which radio should the roadside units use? It looks like a technical detail. It’s a decision with a long tail, because the units will outlast several vehicle generations, and the answer settles which of those vehicles they can talk to.
The answer takes two steps. First, define the services and the interoperability the authority needs. Then specify the access technology separately: the technology family, its generation, its communication mode and its migration path.
What are the two technology families?
For direct vehicle-to-infrastructure communication, usually shortened to V2I, in the European 5.9 GHz band, the two main access-technology families are ITS-G5 and C-V2X.
ITS-G5 is the ETSI access-layer family for European cooperative ITS in the 5.9 GHz band. Its current Release 2 specification, ETSI EN 303 797, is based on IEEE 802.11 vehicular communication (formerly 802.11p) and adds an optional profile based on the IEEE 802.11bd amendment, which can still transmit the legacy format older receivers decode.
C-V2X technology is cellular vehicle-to-everything, specified by 3GPP. In Europe, its direct (PC5 sidelink) access layer is standardised in ETSI EN 303 798 in two generations, LTE-V2X and NR-V2X, both at 3GPP Release 16.
The two families use different radio access layers and cannot communicate with each other directly over the air. Nor can they yet share a channel: ETSI studied co-channel coexistence in TR 103 766 but, in an October 2022 statement to CEPT, reported no consensus on any mechanism.
Why is “DSRC” a risky word in a specification?
DSRC, dedicated short-range communications, appears in specifications and supplier material with at least three meanings. In US connected-vehicle terminology, it refers to the 5.9 GHz WAVE family built on IEEE 802.11p. Some Gulf documents treat it as a synonym for ITS-G5: Saudi Arabia’s spectrum regulator defines DSRC as “also referred to as ITS-G5”. In Europe, CEN DSRC is a separate 5.8 GHz system used for electronic tolling, which 5.9 GHz stations of both families must protect: EN 303 797 and EN 303 798 both require conformance with ETSI TS 102 792, and EN 303 798 caps C-V2X output at 10 dBm e.i.r.p. inside a protection zone.
A tender that simply says “DSRC” is therefore ambiguous. Name the technology family and the standard instead.
Did the EU choose a radio?
It came close. In March 2019, the European Commission adopted a delegated regulation on C-ITS that would, in effect, have based deployment on ITS-G5. The Council objected in July 2019; its official outcome records that Member States supported the objective, while the vast majority expressed concerns of a legal and technological nature. Technology neutrality was one of the objections raised along the way: Finland’s written position argued that the act was not technologically neutral because it contained only one short-range technology. The current framework points in the same direction. The amended ITS Directive, (EU) 2023/2661, states in recital 12 that requirements for ITS systems, in particular C-ITS, should neither impose nor discriminate in favour of a particular type of technology, and that where complementary, reliable and real-life tested C-ITS technologies can be used, coexistent applications should be enabled while ensuring interoperability.
None of that removes the choice. A road authority still has to specify what its roadside units will transmit.
Which C-V2X is the tender asking for?
A tender that asks for “C-V2X technology” leaves two separate questions unanswered: which access generation, and which communication path?
The generation matters because EN 303 798 states plainly that LTE-V2X and NR-V2X are different access layers. The standard says it contains no backwards-compatibility requirements except those explicitly stated in clause 5.7.5, which concern LTE-V2X Release 16 and Release 14; which of the two a channel uses is left to system-level configuration, and running both in the same channel is “not intended”. Later 3GPP releases add dynamic LTE/NR sidelink co-channel coexistence (TS 38.300, clause 16.9.3.4); the Release 16 based EN does not.
The communication path matters as well. Over the PC5 interface, vehicles and roadside units communicate directly without routing the exchange through a mobile network, which suits low-latency local use cases. Over the Uu interface, communication goes through the operator network and supports network-mediated services over wider areas; the 3GPP TS 23.287 architecture treats them as separate modes.
How do the main markets differ?
The United States, Europe and Saudi Arabia illustrate three different regulatory positions; China, which reserved 5,905 to 5,925 MHz for LTE-V2X direct communication in 2018, is a fourth.
In the United States, the Federal Communications Commission reallocated the 5.9 GHz band in 2020: the lower 45 MHz to unlicensed use and the upper 30 MHz, 5.895 to 5.925 GHz, to intelligent transport systems using C-V2X. A 2024 order codified the C-V2X rules with a two-year DSRC sunset: per 5GAA’s FAQ, DSRC operations end on 14 December 2026. Industry deploys LTE-V2X in 5,905 to 5,925 MHz and regards direct NR-V2X as not applicable there. That is a clear regulatory choice.
Europe’s framework favours technological neutrality: Decision (EU) 2020/1426 harmonises 5,875 to 5,935 MHz for safety-related ITS in 10 MHz channels, road ITS prioritised below 5,915 MHz. ITS-G5 occupies 5,895 to 5,905 MHz, and 5GAA’s band-configuration proposal keeps it there while placing NR-V2X sidelink at 5,875 to 5,895 MHz. ITS-G5 also remains an active specification base. The C-Roads Platform’s July 2026 release of its harmonised C-ITS specifications shows the platform maintaining ITS-G5 roadside and mobile system profiles alongside an IP-based interface profile. That should not be confused with a roadside unit supporting both ITS-G5 and C-V2X radios.
The Gulf is not one market either. Saudi Arabia’s regulator has identified the upper 20 MHz, 5,905 to 5,925 MHz, for C-V2X, while reserving the remaining 50 MHz for future identification. The same document notes that consultation views diverged on whether C-V2X or DSRC/ITS-G5 should be implemented, and that CST has received no trial applications for the 20 MHz band since assigning it.
What should a road authority specify?
Start with the C-ITS services and the interoperability they require: hazardous location warnings, in-vehicle signage, signal phase and timing, carried by messages such as CAM, DENM, IVIM, SPATEM and MAPEM, and the certificate architecture that secures them. Then specify how those services will be carried.
Four questions follow. Which vehicles in your market, now and over the equipment’s life, use which technology family and generation? Can the roadside unit support more than one access technology, and can you replace its radio modules independently of the controller? Which C-V2X communication path does the design rely on, PC5 or Uu? And what happens to the installed base if the regional vehicle mix changes after installation?
Frequently asked questions
What is the difference between ITS-G5 and C-V2X?
ITS-G5 and C-V2X are different access-technology families for cooperative vehicle communication. ITS-G5 is ETSI’s 802.11-based European ITS technology. C-V2X includes LTE-V2X and NR-V2X, with direct PC5 communication as well as network-mediated Uu communication. Their radio interfaces are not directly interoperable.
What does DSRC mean in a V2X specification?
It depends on who is using the term. In US terminology, it means the 5.9 GHz WAVE family built on IEEE 802.11p; some Gulf documents use it as a synonym for ITS-G5; in Europe, CEN DSRC is a separate 5.8 GHz tolling technology. A specification should name the technology and standard instead.
Did the EU choose a V2X technology?
No. In 2019, the Council objected, on legal and technological grounds, to a Commission delegated regulation that would in effect have based C-ITS on ITS-G5. The amended ITS Directive, (EU) 2023/2661, states in recital 12 that C-ITS requirements should neither impose nor favour a particular technology.
What is the difference between LTE-V2X and NR-V2X?
Both are C-V2X technologies, but ETSI EN 303 798 treats them as different access layers, with no general backwards compatibility between them. A roadside unit specified for one will not automatically communicate with vehicles using the other, so a tender needs to state the generation.
Lillyneir designs and integrates V2X communication infrastructure for road authorities, working with both 802.11p-based and C-V2X systems, from roadside units through to the certificate management that secures them. If you are deciding how to specify V2X for a corridor, we are glad to talk it through.
