V2X use cases — what it is actually for.
Vehicle-to-everything communication is a way of moving trustworthy statements between road users, infrastructure and backends. What it is for is a separate question, and it has a published answer. ETSI and 3GPP both maintain catalogues of V2X use cases, and between them they cover road safety, cooperative driving, shared perception, traffic operations, automated mobility, public transport, freight, parking and emergency response.
This page is that catalogue, reorganised by the thing that actually determines how hard each one is to build: whether a station is sharing its status, its intent, or an agreed manoeuvre. Underneath it are three deep dives into operating environments — public roads, private industrial sites and guided transit — where the same messages run into very different constraints.
Two standards bodies have already written the list. They answer different questions.
Nothing on this page is a proprietary taxonomy. The application families below are the ones ETSI and 3GPP publish, and the divergence between the two is not an inconsistency — it is the difference between what an application means and what a radio has to do.
ETSI TR 102 638 V2.1.1 (April 2024) is the Release 2 Basic Set of Applications. It catalogues ITS services and their constituent use cases from the application side: what the situation is, which stations are involved, what each one needs to know. Its Release 2 service families are partial and high automation; CCAM augmented perception; vehicles' coordination; multi-car collision avoidance; intersection crossing assist; advanced warning and information with VRU protection; dynamic navigation; contextual dedicated corridor management; points-of-interest management; agricultural applications; integration of C-ITS into public warning systems; and vehicle lawful interception. The report states plainly that the list is not exhaustive.
3GPP TS 22.186 approaches the same territory from the network side and reduces it to four enhanced-V2X groups: vehicles platooning, advanced driving, extended sensors and remote driving. That is not a shorter list of applications; it is a list of requirement profiles — latency, reliability, data rate and range envelopes that a radio has to satisfy. An application designer reads ETSI. A radio and platform designer reads 3GPP. A product programme needs both, because the second decides whether the first is buildable on the hardware you selected.
A third layer sits underneath: the message sets. CAM, DENM, CPM, VAM and the TS 103 301 infrastructure messages in Europe and the Indian stack; BSM, PSM, SDSM, SPaT, MAP and TIM as the SAE J2735 counterparts in North America. Almost every use case below is a combination of an ETSI service family, a 3GPP requirement profile and a message set, and the interesting engineering questions live at the joins.
The single most useful way to sort V2X applications, and it is not by vehicle type.
ETSI's Release 2 report divides cooperation into three classes. They differ in what a station tells the world about itself, and each step up raises the trust, latency and liability requirements sharply.
| Class | What is shared | Consequence for the system |
|---|---|---|
| Awareness — status sharing | Where a station is, how fast, in which direction, and what it has just detected | Extends each vehicle's perception beyond its own sensors and beyond line of sight. Deployed today; carried by CAM and DENM, and by CPM where collective perception is present. |
| Intent sharing | What a station is about to do — a planned trajectory or a short-term manoeuvre | Turns prediction from inference into declaration. Specification and pilot stage. A false intent is more dangerous than a false position, so misbehaviour detection matters more here, not less. |
| Manoeuvre coordination | An agreed collective action, negotiated between stations or prescribed by infrastructure or a supervisor | The vehicle acts on something another party decided. Largely research and pilot. This is where authentication, authorisation and liability stop being paperwork. |
The site's Day 1 / Day 2 / Day 3 framing maps onto this almost exactly: Day 1 is awareness, Day 2 adds collective perception and vulnerable-road-user awareness, Day 3 is coordination. Reading a vendor roadmap against these three classes is the fastest way to tell a shipping capability from a slide.
By operational problem, with the mode and the message set that carry it.
Mode is the communication path the use case predominantly needs, not the only one it can use. Maturity uses the deployment vocabulary from the message-sets page rather than a vendor readiness scale.
Road safety and hazard warning. The oldest family, and still the one carrying the deployment case.
| Use case | Actors | Mode | Carried by | Maturity |
|---|---|---|---|---|
| Intersection collision warning | Vehicles; signal or RSU where present | V2V, V2I | CAM; SPATEM and MAPEM | Day 1 |
| Signal violation warning | Vehicle, signal controller | I2V | SPATEM, MAPEM | Day 1 |
| Emergency electronic brake light | Vehicles | V2V | DENM | Day 1 |
| Forward collision and rear-end warning | Vehicles | V2V | CAM, DENM | Day 1 |
| Wrong-way driving warning | Vehicles; infrastructure | V2V, I2V | DENM | Day 1 |
| Stationary or disabled vehicle warning | Vehicles; RSU | V2V, I2V | DENM | Day 1 |
| Roadworks warning | Works vehicle or RSU, vehicles | I2V | DENM, IVIM | Day 1 |
| Emergency vehicle approaching | Emergency vehicle, vehicles | V2V | DENM | Day 1 |
| Slow vehicle and motorcycle-specific warnings | Vehicles, powered two-wheelers | V2V | CAM, DENM | Day 1 to Day 2 |
| Non-line-of-sight hazard awareness | Any station in the relevant area | V2V, V2I | DENM with geographic dissemination | Day 1 |
Vulnerable road users. Given its own family in Release 2, and the one that matters most in Indian traffic. The V2P mode in detail →
| Use case | Actors | Mode | Carried by | Maturity |
|---|---|---|---|---|
| VRU presence awareness | Pedestrian, cyclist or rider device; vehicles | V2P | VAM; PSM as the SAE counterpart | Day 2 |
| VRU collision warning | VRU device, vehicles | V2P, V2V | VAM, DENM | Day 2 |
| Infrastructure-detected VRU | RSU with sensors, vehicles | I2V | CPM | Day 2 |
| VRU cluster management | Groups of VRUs, vehicles | V2P | VAM clustering | Day 2 |
| Interactive VRU crossing | VRU, vehicle, crossing infrastructure | V2P, V2I | VAM with infrastructure messages | Day 3 |
Cooperative perception. Sharing what your sensors see rather than only where you are. This is the family that answers the low-penetration objection, because one equipped station becomes a sensor for everything around it — including unequipped road users.
| Use case | Actors | Mode | Carried by | Maturity |
|---|---|---|---|---|
| Detected-object sharing | Vehicles, RSUs | V2V, V2I | CPM; SDSM as the SAE counterpart | Day 2 |
| Perception of a non-connected vehicle at an intersection | Equipped vehicle or RSU, other vehicles | V2V, I2V | CPM | Day 2 |
| Occluded-object awareness | Vehicles, infrastructure sensors | V2V, I2V | CPM | Day 2 |
| Infrastructure-assisted perception in tunnels and on gradients | RSU with sensors, vehicles | I2V | CPM, DENM | Day 2 |
| Local map and road-attribute updates | Road operator, vehicles | I2V, V2N | MAPEM, IVIM; backend distribution for larger payloads | Day 1 to Day 2 |
Cooperative driving and manoeuvre coordination. Where intent-sharing begins. The message that carries manoeuvre coordination in Europe is still in development, so no specification number is cited for it here.
| Use case | Actors | Mode | Carried by | Maturity |
|---|---|---|---|---|
| Cooperative lane change | Vehicles | V2V | Intent and coordination messaging | Day 3 |
| Cooperative lane merging | Vehicles; infrastructure where a merge is managed | V2V, V2I | Intent and coordination messaging | Day 3 |
| Cooperative adaptive cruise control and C-ACC strings | Vehicles in sequence | V2V | CAM at high rate; 3GPP advanced-driving profile | Day 2 to Day 3 |
| Truck platooning management | Lead and following trucks; fleet backend | V2V, V2N | 3GPP platooning profile | Day 3 |
| Cooperative transition control | Automated vehicle, infrastructure | V2I | Infrastructure support for automated driving | Day 3 |
| Dynamic intersection management | Signal or intersection controller, vehicles | I2V, V2I | SPATEM, MAPEM, SREM and SSEM | Day 2 to Day 3 |
| Coordinated movement through constrained space | Vehicles; a supervisor where one exists | V2V, V2I | Intent and coordination messaging | Day 3 |
Traffic, infrastructure and network operations. The family with the most measured efficiency evidence behind it. What has actually been measured →
| Use case | Actors | Mode | Carried by | Maturity |
|---|---|---|---|---|
| Signal phase and timing, lane geometry | Signal controller, vehicles | I2V | SPATEM, MAPEM | Day 1 |
| Green-light optimal speed advisory | Signal, vehicle | I2V | SPATEM, MAPEM | Day 1; automated and negotiated variants Day 3 |
| Signal priority and pre-emption | Bus or emergency vehicle, signal controller | V2I, I2V | SREM request, SSEM response | Day 1 |
| In-vehicle information: speed limits, restrictions, events | Road operator, vehicles | I2V | IVIM | Day 1 |
| Road-condition and weather information | Vehicles, road operator | V2I, I2V, V2N | DENM; aggregation in the backend | Day 1 to Day 2 |
| Lane closures, hard-shoulder running, corridor management | Road operator, vehicles | I2V | IVIM, DENM | Day 1 to Day 2 |
| Detour and dynamic routing | Traffic-management centre, vehicles | V2N | Backend services over cellular | Day 1 |
| Traffic-flow optimisation across a network | Traffic-management centre, RSUs, vehicles | V2N2X | Backend aggregation with local dissemination | Day 2 |
| Public-warning integration | Public authority, vehicles | V2N, I2V | Public warning system feeding DENM or IVIM | Day 2 |
Automated and remotely operated mobility. The 3GPP requirement profiles bite hardest here: extended sensors and remote driving are the two that will not fit inside a Day-1 radio budget.
| Use case | Actors | Mode | Carried by | Maturity |
|---|---|---|---|---|
| Infrastructure support for automated driving | RSU, automated vehicle | I2V | CPM, MAPEM, IVIM | Day 2 to Day 3 |
| Tele-operated driving and remote assistance | Remote operator, vehicle | V2N | 3GPP remote-driving profile over cellular | Day 3 |
| Automated valet parking | Vehicle, facility infrastructure | V2I | Facility messaging with infrastructure guidance | Day 3 |
| Automated shuttle and pod operation | Pod, station, fleet control, other road users | V2I, V2N, V2V | CAM, DENM, CPM plus fleet backend | Day 2 to Day 3 |
| Fleet coordination and depot movements | Vehicles, depot systems | V2N, V2I | Backend orchestration with local awareness | Day 2 |
Public transport, freight and points of interest.
| Use case | Actors | Mode | Carried by | Maturity |
|---|---|---|---|---|
| Bus priority and connected transit operations | Bus, signal controller, operations centre | V2I, V2N | SREM, SSEM, CAM | Day 1 |
| Emergency-corridor and priority-vehicle management | Emergency vehicle, infrastructure, other vehicles | V2V, V2I | DENM, SREM | Day 1 to Day 2 |
| Road-worker safety | Worker device or works vehicle, approaching traffic | V2P, I2V | VAM, DENM | Day 2 |
| Freight corridor and terminal movements | Trucks, terminal systems, gates | V2I, V2N | Local messaging plus backend orchestration | Day 2 |
| Toll plaza and gate guidance | Vehicle, plaza infrastructure | V2I | Infrastructure guidance messaging | Day 2 |
| Parking availability and booking | Vehicle, parking operator | V2N, V2I | Backend services; IVIM for local signage | Day 1 to Day 2 |
| Railway level crossing state | Crossing infrastructure, road vehicles | I2V | DENM, IVIM | Day 2 |
What the table does not say. That every deployment needs both an on-board and a roadside unit. A V2V-only warning set needs no roadside infrastructure at all; a signal-phase service needs infrastructure and gains nothing from vehicle-to-vehicle range. Deciding which half of the system a programme is actually buying is the first architectural decision, and it is made far too late in most programmes. Why V2I deploys first →
“Cars talk to cars” is wrong in a way that costs money at the hardware stage.
| Mode | Path | Suits |
|---|---|---|
| V2V | Direct PC5 sidelink between vehicles | Sub-100 ms safety warnings with no network dependency and no subscription. The only mode that works where there is no coverage. |
| V2I and I2V | Direct PC5 between a vehicle and a roadside unit | Signal phase, lane geometry, local hazards, infrastructure-detected objects. Fixed, surveyed, known-location endpoints. |
| V2P | Direct, to or from a pedestrian, cyclist or rider device | Vulnerable-road-user awareness. Constrained by handset power and duty cycle far more than by radio design. |
| V2N | Cellular Uu to a network service | Credentials and trust lists, map and software updates, traffic services, fleet orchestration, remote operation. Higher and more variable latency; needs coverage and a subscription. |
| V2N2X | Vehicle to network to another station, via a backend | Reaching stations that are out of direct range, and aggregating across a whole network. Useful; not a substitute for direct communication in a collision-imminent case. |
The practical consequence is a bill of materials. A unit built only for direct communication cannot fetch its own credentials or receive a trust-list update, and a unit built only for cellular cannot warn anyone in a tunnel. Most real programmes need both radios, and the two paths carry different security material with different lifetimes. The direct-versus-network comparison → · What C-V2X actually specifies →
The same message sets. Very different constraints, regulators and failure modes.
Grouping by radio technology hides the distinction that actually drives design. Grouping by operating environment exposes it.
Public roads
Mixed traffic, licensed or licence-exempt spectrum, a national trust framework, and no control over who else is on the channel.
Private industrial sites
One operator controls the site, the fleet and the rules — and carries the whole safety case. Heavy equipment, poor sight lines, no public spectrum entitlement.
Guided and automated transit
Pods, people movers and monorails, where a rail-derived safety regime meets road traffic at the edges.
Ports, airside vehicles, warehouses, quarries, construction sites and factory campuses sit alongside mining in the private-site column: same absence of public-spectrum entitlement, same single accountable operator, same mixed autonomous and manual fleet. The mining page treats that column in depth because it is the environment with the most mature published safety framework behind it; the reasoning transfers to the others with the hazard model changed.
Agriculture is a separate ETSI Release 2 family in its own right, covering task-data exchange, geo-referenced data, agricultural platooning, in-field safety and work awareness. It is catalogued here for completeness and is not treated further on this site.
A use case is only as good as the receiver's reason to believe it.
Each use case above ends with a receiver acting on something a stranger transmitted. That makes authenticated messaging a precondition rather than a feature: the receiver has to establish that the sender holds an accepted credential, is authorised to send that message type, and that the content was not altered. How V2X PKI does that →
Authentication is not truthfulness. A correctly signed message can still be wrong, through a spoofed position source, a compromised platform or a cloned device, which is why misbehaviour detection is a distinct layer with its own reporting standard. The reporting service → · The demonstrated attacks →
Separate the architecture from the policy. The technical architecture — enrolment and authorisation credentials, pseudonymity, short validity, offline verification — is broadly common across regimes. Which authorities exist, who may operate them and what a device must prove before admission is decided jurisdiction by jurisdiction, and differently in each. A private industrial site is different again: there is no national trust framework to join, and the site operator ends up being its own policy authority. The four trust models compared → · Where India has and has not decided →
The building blocks, not the deployment.
Ambimat develops and customises V2X hardware and software building blocks for vehicle OEMs, tier suppliers, infrastructure vendors, research programmes and system integrators: on-board unit and roadside unit development platforms, the embedded engineering around them, device-side security and credential integration, and application and integration work scoped per programme. V2X development services →
Ambimat does not operate road networks, traffic-management centres, mine sites or trust services, and does not certify or homologate equipment — type approval sits with the authorised bodies. AmbiOBU and AmbiRSU are development platforms rather than orderable products, and their published specifications are the boundary of what they do: notably, the on-board unit carries a cellular module and a direct C-V2X radio but no vehicle data bus interface and no lidar, radar or camera hardware. The specification →
Where each of these is worked out properly.
Message sets
CAM, DENM, CPM, VAM and the SAE counterparts, with rates and specification numbers.
What V2X is for
The measured evidence, and the honest counter-case.
V2X PKI
The trust layer every use case on this page depends on.
ITS station architecture
Where an application sits in the stack, and what it can assume.
Regulation
Which of these are permitted, mandated or unaddressed, jurisdiction by jurisdiction.
V2X Intelligence
Current deployments, standards activity and research across these use-case families, refreshed from monitored sources.
Questions this page answers.
What are the main V2X use cases?
They group into road safety and hazard warning; vulnerable-road-user protection; cooperative perception; cooperative driving and manoeuvre coordination; traffic and infrastructure services such as signal phase and timing, priority and in-vehicle information; automated and remotely operated mobility; public transport, freight and parking services; and emergency-vehicle operations. ETSI TR 102 638 V2.1.1 catalogues these as Release 2 ITS services and states explicitly that the list is not exhaustive.
What is the difference between the ETSI and 3GPP V2X use case lists?
They answer different questions. ETSI TR 102 638 describes what an application means — the situation, the stations involved and what each needs to know. 3GPP TS 22.186 reduces the same territory to four requirement profiles — vehicles platooning, advanced driving, extended sensors and remote driving — which express latency, reliability, data rate and range envelopes a radio has to satisfy. Application designers read the first; radio and platform designers read the second.
Does every V2X use case need a roadside unit?
No. A vehicle-to-vehicle warning set — emergency electronic brake light, forward collision warning, emergency vehicle approaching — needs no roadside infrastructure at all. Signal phase and timing, in-vehicle information and infrastructure-assisted perception need infrastructure and gain nothing from vehicle-to-vehicle range. Which half of the system a programme is buying is an architectural decision that should be made early.
Which V2X use cases are actually deployed today?
The awareness and warning set: cooperative awareness and event notification between vehicles, signal phase and timing, in-vehicle information, roadworks warning, emergency vehicle approaching, and signal priority. Collective perception and vulnerable-road-user awareness have published specifications and early deployment. Manoeuvre coordination, platooning and cooperative automated driving remain largely research and pilot.
Does V2X apply outside public roads?
Yes, and the constraints change substantially. On a private industrial site such as a mine, port or airport there is no public ITS spectrum entitlement and no national trust framework to join, so the site operator ends up writing its own credential policy; the population is closed and known, so pseudonymity is usually not wanted. Guided transit is different again: automotive V2X belongs at the boundary where a guided system meets road traffic, not inside its train-control system.
Last updated 2026-09-07 · Technical reference maintained by Ambimat Electronics, Ahmedabad, India. Corrections: neel.shah@ambimat.com