Introduction

The UK is moving towards a more connected and data-driven transport network. Smart motorways, roadside IoT devices, and Vehicle-to-Everything (V2X) communication create new opportunities for safety, efficiency, and traffic management. These systems rely on thousands of digital interactions every second, exchanging information about speed, lane closures, weather conditions, congestion, and roadside hazards.

For these systems to operate safely, every device involved must be trusted. Messages must be authenticated, data must be encrypted, and commands must be verifiable. Public Key Infrastructure (PKI) and Certificate Lifecycle Management (CLM) enable this trust.

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Why Intelligent Transport Systems Need PKI

Intelligent Transport Systems (ITS) introduce a range of communication flows that must be secured, including:

• Vehicle-to-Infrastructure (V2I)
• Vehicle-to-Network (V2N)
• Vehicle-to-Vehicle (V2V)
• Infrastructure-to-Infrastructure (I2I)

These interactions only work safely when devices and software components can verify each other’s identity and prevent spoofed or manipulated data.

PKI provides the foundation for digital trust by issuing cryptographic certificates that verify the authenticity and integrity of communications.

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Risks When V2X Communications Are Not Properly Secured

Without strong PKI and CLM processes, connected transport systems face significant risks, such as:

• False or spoofed traffic messages
• Compromised roadside devices issuing unsafe instructions
• Inability to authenticate over-the-air updates for field equipment
• Broadcast of inaccurate congestion, hazard, or diversion information
• Reduced ability to investigate or audit cyber incidents

In a safety-critical environment, incorrect or malicious messages can have real-world consequences for drivers, highways teams, and emergency responders.

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Where PKI Is Applied in Smart Motorway and V2X Infrastructure

PKI is used to secure trust for a wide range of devices and systems, including:

• Variable Message Signs (VMS)
• Speed and lane control signage
• Roadside sensors and weather detection systems
• Ramp metering and traffic flow management tools
• Connected vehicle edge units
• Incident detection and monitoring platforms

These devices frequently operate for long periods without physical access, making remote certificate updates and revocation essential.

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The Importance of Certificate Lifecycle Management (CLM)

As the number of certificates in V2X networks grows, manual management quickly becomes unworkable. CLM allows transport operators to:

• Discover all certificates across roadside and cloud-connected assets
• Monitor and replace certificates approaching expiry
• Automate renewal and provisioning through secure workflows
• Revoke trust rapidly if a device is compromised
• Support cryptographic change, including future post-quantum standards

CLM ensures that certificate management scales as connected infrastructure expands.

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Strategic Benefits for UK Highways and V2X Programmes

A mature PKI and CLM approach supports:

• Safety and reliability of live traffic management systems
• Secure adoption of autonomous and connected vehicle innovations
• Effective lifecycle control for remote and hard-to-reach devices
• Faster deployment of new roadside and edge computing technology
• Stronger compliance with emerging connected transport regulations

This enables highway authorities and transport integrators to modernise confidently.

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The Role of Unsung Ltd

Unsung Ltd supports PKI and CLM implementations for connected and intelligent transport environments, including:

• PKI design tailored for V2X and smart motorway architectures
• Discovery of certificates across roadside, data centre, and cloud systems
• Integration with device management, HSMs, and operational technologies
• Governance, trust policy, and operational model development
• Planning for crypto-agility and long-term cryptographic transition

The objective is a scalable digital trust approach that supports the next generation of mobility.

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Conclusion

Connected transport systems offer significant benefits for safety, efficiency, and national infrastructure performance. However, these systems only function reliably when digital trust is maintained. PKI and Certificate Lifecycle Management provide the secure foundation required to authenticate devices, verify commands, and protect data across V2X and smart motorway environments.

A strong PKI strategy ensures that the UK can continue to evolve towards safer, smarter, and more resilient transport networks.

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