Knowledge Base

Everything you need to know and understand to develop V2X applications.

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Introduction to V2X

Vehicle-to-Everything (V2X) is a transformative communication technology that enables vehicles to exchange information with each other and their surroundings in real time. This continuous connectivity improves road safety, enhances traffic efficiency, and lays the foundation for autonomous driving.

V2X communication encompasses several interaction types:

  • V2V (Vehicle-to-Vehicle): Direct exchange of data such as speed, position, sensor data, and direction between vehicles.
  • V2I (Vehicle-to-Infrastructure): Communication with traffic lights, road signs, and roadside units.
  • V2P (Vehicle-to-Pedestrian): Protection of vulnerable road users such as cyclists and pedestrians.
  • V2N (Vehicle-to-Network): Connectivity to cloud or backend systems for real-time traffic and system updates.

The Evolution of V2X

To standardize and structure the rollout of V2X systems, the industry classifies applications into Day 1, Day 2, and Day 3 stages — each representing an increasing degree of intelligence, data sharing, and automation.

Day 1: Foundational Safety Applications

Day 1 applications deliver the first tangible safety benefits of V2X. At this stage, vehicles broadcast ego data — their own position, speed, and heading — but do not yet share sensor information such as camera or radar data.

Typical use cases include:

  • Emergency Electronic Brake Light (EEBL): Warns following vehicles when a car ahead brakes suddenly.
  • Forward Collision Warning (FCW): Alerts drivers to imminent frontal collisions.
  • Intersection Movement Assist (IMA): Warns of potential intersection collisions.
  • Emergency Vehicle Approaching (EVA): Warns when an emergency vehicle is approaching.

These applications rely on direct, low-latency communication between vehicles and infrastructure, enhancing driver awareness and reducing reaction times.

Driving Awareness and Road Safety

Avoid collisions by giving drivers early warnings about dangerous situations involving other vehicles. V2X acts as additional sensor in the vehicle and in contrast to an ADAS system it detects a dangerous situation far in advance.

Day 2: Cooperative Awareness and Traffic Optimization

Day 2 introduces cooperative perception and semi-automated driving features. Vehicles now exchange sensor-level data (raw or processed from radar, lidar, or cameras) in addition to ego data, providing a richer, more comprehensive understanding of the environment — even beyond line of sight.

Examples include:

  • Cooperative Adaptive Cruise Control (CACC): Vehicles synchronize speed and distance to optimize traffic flow.
  • Advanced VRU protection: Real-time V2X-based alerts and control actions for pedestrians and cyclists.
  • Green Light Optimal Speed Advisory (GLOSA): Advises drivers on optimal speed to pass traffic lights during green phases.

Day 2 applications mark the transition from simple information sharing to coordinated behavior between vehicles.

Cooperative Perception

V2X messages can be generated for non-V2X traffic users. A vehicle will not only share its own data but also position information of other detected non-V2X traffic users.

Day 3: Cooperative and Automated Driving

Day 3 envisions a fully connected, automated mobility ecosystem. Vehicles and infrastructure collaborate in real time to coordinate complex maneuvers and ensure the highest safety levels for all road users.

Key aspects include:

  • Full autonomous driving: Vehicles navigate complex environments with minimal human involvement.
  • Cooperative maneuvers: Automated coordination of lane changes, merging, and intersection management.
  • Platooning: Multiple vehicles travel in coordinated formations to reduce fuel consumption and congestion.

Achieving this stage requires ultra-reliable, low-latency, and secure communication networks, combined with advanced onboard intelligence and edge/cloud computing.

Cooperative Maneuvering and Flow Control

We believe the full power of V2X will be unleashed in traffic-flow control automatically leading to a safer traffic. Imagine the potential of traffic jam and accident reduction by feeding V2X data into autonomous systems.

V2X is Evolving

V2X is evolving from simple data exchange toward a fully cooperative and automated mobility ecosystem. Understanding the Day 1–3 progression helps developers design applications that scale with future standards and infrastructure — bridging today’s safety solutions with tomorrow’s autonomous mobility

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