EU C-ITS Deployment Mandate 2027: Transport Agency Guide

The EU's cooperative intelligent transport system framework has moved from pilot to mandate. Directive (EU) 2023/2661, adopted in November 2023, revised the ITS Directive to cover C-ITS, connected automated mobility, and multimodal digital services. Member states had until 21 December 2025 to transpose the amending directive into national law. The Commission's 2026-2027 working programme now targets delegated acts defining binding specifications for C-ITS interoperability, security credential management, and data sharing. Germany has already deployed the largest C-ITS project in Europe - 1,000 ITS Roadside Stations across 8,600 km of Autobahn. For Program Directors and VP Engineers at EU transport agencies, the EU C-ITS deployment mandate is no longer a planning exercise. It is an engineering programme with specifications due before 2027.

• The directive is transposed: EU member states were required to transpose Directive 2023/2661 into national law by December 2025, extending the ITS framework to cover C-ITS, automated mobility, and multimodal services.
• Delegated acts define the engineering scope: The Commission's 2026-2027 programme targets binding specifications for C-ITS service interoperability, PKI security credentials, and data-quality standards for vehicle-infrastructure communication.
• Germany leads deployment: Kapsch TrafficCom and Autobahn GmbH completed Phase 1 of Europe's largest C-ITS project - 1,000+ ITS Roadside Stations across German motorways coordinated with 120 highway maintenance departments.
• Day 1 services define the minimum: Roadworks warnings, hazardous location alerts, traffic jam notifications, and SPAT/MAP intersection data are the first tier of mandated C-ITS services with harmonised C-Roads specifications already published.
• Hybrid communication architecture is required: EU C-ITS operates on ETSI ITS-G5 (5.9 GHz short-range) with cellular backhaul provision - transport agencies must engineer for both communication paths.
• EUR 25.8 billion backs the mandate: The Connecting Europe Facility Transport programme (2021-2027) funds C-ITS corridor deployments, with EUR 2.8 billion awarded across 94 projects in the 2025 call alone (CINEA, 2025).

What Is the EU C-ITS Deployment Mandate for 2027?

The EU C-ITS deployment mandate is a layered regulatory framework, not a single regulation. It builds on the revised ITS Directive (Directive 2010/40/EU as amended by Directive 2023/2661), which gives the Commission authority to adopt delegated acts defining binding technical specifications for four priority areas: traffic information, traffic management continuity, road safety, and vehicle-infrastructure integration.

The 2023 revision significantly expanded scope. The European Commission's ITS Directive page confirms that the revised rules cover emerging services including cooperative ITS communication between vehicles and infrastructure, automated mobility, and multimodal booking and ticketing platforms. The directive also mandates digitisation of safety-critical road data - speed limits, roadworks locations, and multimodal access nodes.

The engineering impact comes through the delegated acts scheduled for 2026-2027. These will define binding specifications for C-ITS security credential management, interoperability requirements for cooperative services, and data-quality standards for information flowing between vehicles, roadside infrastructure, and traffic management centres. Once adopted, compliance is mandatory for any entity deploying C-ITS services or stations within the EU.

What Are the Risks of Missing the C-ITS Engineering Window?

Transport agencies that delay C-ITS engineering face three categories of risk:

Operational isolation. As member states deploy interoperable C-ITS services on motorway and urban networks, agencies without compliant systems cannot participate in cross-border cooperative services, cannot receive or relay safety-critical messages from connected vehicles, and cannot contribute data to the European Mobility Data Space that the Commission is developing alongside the ITS specifications.

Funding exclusion. The Connecting Europe Facility Transport programme has a total budget of EUR 25.8 billion for 2021-2027, and C-ITS corridor deployments are eligible. The 2025 CEF General Call awarded EUR 2.8 billion across 94 projects. Agencies without credible deployment plans and conformance with harmonised specifications will lose access to this funding in the remaining programme cycles.

Procurement bottleneck. The engineering talent for C-ITS system integration - spanning radio communications, PKI security, real-time message processing, and traffic management system integration - is specialised. Agencies that delay their programmes will compete for the same mission-critical engineering partners as agencies that started earlier, but with tighter timelines and less negotiating leverage.

What Must Transport Agencies Engineer for C-ITS Compliance?

The engineering scope for C-ITS compliance breaks into five layers:

Communication infrastructure

EU C-ITS operates on a hybrid communication model. The short-range layer uses ETSI ITS-G5 (standardised as ETSI EN 302 663) in the 5.9 GHz band for direct vehicle-to-infrastructure (V2I) and vehicle-to-vehicle (V2V) communication. ITS-G5 provides locally self-organising ad-hoc networks that operate without subscription, perform at any location, and meet functional safety requirements. The successor standard IEEE 802.11bd improves performance while maintaining backward compatibility.

On the cellular side, C-V2X provides complementary long-range communication. Transport agencies must engineer roadside infrastructure to support ITS-G5 at minimum, with architectural provision for cellular backhaul and future C-V2X integration.

Day 1 service applications

The EU defined C-ITS deployment in service tiers. Day 1 services - the first mandated tier - include hazardous location notifications, roadworks warnings, weather conditions alerts, traffic jam ahead warnings, slow/stationary vehicle alerts, and signal phase and timing (SPAT/MAP) data. The C-Roads platform has published harmonised specifications defining message formats, triggering conditions, and quality-of-service parameters for each service.

Roadside ITS stations must generate, receive, and relay standardised DENM (Decentralized Environmental Notification Messages) and CAM (Cooperative Awareness Messages) per ETSI EN 302 637. The engineering work extends beyond hardware installation to message generation logic, geographic relevance filtering, and service-level quality thresholds.

Security and trust infrastructure

C-ITS messages must be cryptographically signed and verified. The EU PKI model issues, manages, and revokes certificates used by ITS stations. Engineering teams must implement hardware security modules (HSMs), support ETSI and IEEE certificate formats, and integrate with the EU's Certificate Trust List architecture. GDPR-compliant data handling is required for any personally identifiable information in the cooperative transport stack.

Data exchange and interoperability

Transport agencies must ensure static and dynamic road data - speed limits, roadworks, traffic conditions - is available through standardised machine-readable interfaces. Cross-border corridor operators must validate that their C-ITS services work seamlessly with neighbouring member states' systems against C-Roads Release specifications.

Central management platform

A C-ITS management centre aggregates roadside station data, manages message generation and distribution, interfaces with existing traffic management systems, and provides operational monitoring. Germany's deployment uses Kapsch's cloud-based Connected Mobility Control Centre (CMCC) as a reference architecture for this layer.

How Did Germany Deploy Europe's Largest C-ITS Project?

Germany's C-ITS deployment provides the clearest reference for what production-scale cooperative intelligent transport system engineering looks like in the EU.

In 2025, Kapsch TrafficCom and Autobahn GmbH completed Phase 1 of Europe's largest C-ITS project. Approximately 1,000 ITS Roadside Stations were deployed on mobile barrier panels across 8,600 km of German motorway. The project scope includes around 1,200 roadside units and a cloud-based CMCC that manages the stations and interfaces with existing traffic management systems.

The initial service is construction-zone warnings - approaching vehicles receive real-time DENM alerts about roadworks ahead. Deployment required coordination with 120 highway maintenance departments across Germany. Future phases will add additional cooperative services including hazardous weather warnings and traffic flow management.

For transport agencies evaluating their own C-ITS programmes, the German deployment demonstrates several practical lessons: the scale of coordination required (120 departments), the infrastructure needed (1,000+ roadside stations for a single service), and the phased approach (hardware first, then incremental service addition). Eastgate Software has delivered transport infrastructure systems alongside Autobahn GmbH and Siemens Mobility for over 12 years, building the kind of ITS engineering capability that C-ITS deployment demands.

What Is the Timeline for EU C-ITS Engineering Programmes?

A realistic implementation timeline for a national or regional C-ITS programme:

1. Readiness assessment and architecture (8-12 weeks): Audit existing roadside infrastructure for C-ITS upgrade potential. Define the target zone architecture - which corridors get ITS-G5 coverage first, where the management centre sits, how the C-ITS layer interfaces with existing traffic management. Evaluate communication requirements against ETSI specifications.
2. Procurement and infrastructure deployment (16-24 weeks): Procure ITS Roadside Stations, configure and integrate them. Deploy the central management platform. Implement PKI infrastructure including HSMs, certificate provisioning, and CTL synchronisation. Germany's experience shows this phase requires coordination across many operational departments.
3. Service implementation and testing (8-12 weeks): Implement Day 1 service logic for initial deployment (typically roadworks warning). Test message generation, geographic relevance, and quality-of-service against C-Roads harmonised specifications. Validate cross-border interoperability where applicable.
4. Operational launch and expansion (ongoing): Begin operational service delivery. Monitor system performance and message quality. Add Day 1.5 services incrementally. Feed operational results back into the EU specification process.

Total timeline from programme start to first operational service: 8-12 months. For agencies operating in cross-border corridors (Rhine-Alpine, Nordic, Iberian), add time for interoperability validation with adjacent member states.

What Standards and Compliance Requirements Apply to EU C-ITS?

EU transport infrastructure C-ITS deployments must comply with multiple intersecting standards:

• Directive 2023/2661: The revised ITS Directive. Transposed into national law by December 2025. Creates the legal basis for binding C-ITS specifications.
• C-Roads Harmonised Specifications: Defines message formats, service parameters, and interoperability requirements for Day 1 and Day 1.5 services. The de facto engineering standard for EU C-ITS deployment.
• ETSI ITS-G5 (EN 302 663): Short-range communication standard for the 5.9 GHz band. Mandatory for V2I communication in EU C-ITS deployments.
• ETSI EN 302 637: Defines DENM and CAM message formats and triggering rules.
• NIS2 Directive: C-ITS infrastructure falls under critical infrastructure cybersecurity requirements. Transport operators must ensure their C-ITS systems meet NIS2 supply chain security obligations.
• GDPR: Any processing of vehicle probe data or cooperative awareness messages must implement privacy-by-design controls and data minimisation.
• EU PKI Framework: Security credential management for C-ITS stations, including certificate issuance, revocation, and trust list management.

What Questions Should Transport Engineering Leaders Ask About C-ITS?

How binding are the delegated acts for C-ITS?

Once adopted, delegated acts under the revised ITS Directive are legally binding on any entity deploying C-ITS services or stations. Compliance is mandatory where C-ITS services are deployed - the specifications are not voluntary guidelines. Transport agencies currently deploying against C-Roads specifications will need to align with the final delegated acts once published.

Can we start with a single corridor and expand?

Yes, and this is the recommended approach. Germany began with construction-zone warnings on motorways before planning additional services. The C-Roads platform explicitly supports phased deployment, with Day 1 services as the foundation and Day 1.5/Day 2 services added incrementally. Start with the corridor that has the highest safety impact and the most operational readiness.

What is the relationship between C-ITS and automated driving?

C-ITS provides the vehicle-to-infrastructure communication layer that automated driving systems depend on for real-time hazard awareness, traffic signal timing, and road condition data. The revised ITS Directive explicitly covers connected and automated mobility alongside C-ITS. Transport agencies that deploy C-ITS infrastructure now are building the foundation that automated mobility services will require.

How do we handle the ITS-G5 vs C-V2X technology debate?

The EU's policy position is technology-neutral at the service level - what matters is interoperability, not the underlying radio technology. However, current C-Roads specifications and production deployments (including Germany's Autobahn project) are based on ITS-G5. Engineering teams should deploy ITS-G5 for current services while designing architecture that can accommodate C-V2X as the cellular ecosystem matures.

Where Should Transport Engineering Leaders Start?

Start with a gap assessment against C-Roads harmonised specifications, mapped to your existing infrastructure and planned corridor deployments. Prioritise Day 1 services - roadworks warning and hazardous location notification - because these have the strongest regulatory backing and the most operational precedent. Engage with your national ITS contact point and the C-Roads platform to access current specification releases. For agencies in the German, Austrian, or Nordic corridors, the production deployments already in operation provide concrete engineering baselines to design against. The EU C-ITS deployment mandate timeline is already running. The specifications are being finalised. The engineering work required to meet the 2027 deadline is substantial and well-defined - but only achievable if programmes start now.

The EU C-ITS deployment mandate is not a future planning item. It is a current engineering programme with transposed legislation, live reference deployments, and delegated act timelines that will determine which transport agencies are compliant and which are operationally isolated when the specifications become binding.