SI Interface

Standardizing communication with traffic signal controllers and roadside infrastructure

Deploying connected mobility services at scale requires standardized communication between traffic management systems, traffic signal controllers, roadside infrastructure and mobility service providers. Open interfaces are essential for enabling interoperable, scalable and vendor-independent connected mobility ecosystems.

This whitepaper introduces the SI Interface, an open standard for exchanging real-time mobility data with traffic signal controllers. Originally developed to support one of Europe’s largest operational connected mobility ecosystems, the interface is now used by transportation agencies and infrastructure operators to enable interoperable Networked V2X services and future-ready digital infrastructure.

The whitepaper explores:

• Why standardized interfaces are essential for connected mobility
• Connecting traffic signal controllers to connected mobility services
• Supporting interoperable real-time data exchange
• Reducing complexity through open standards
• Expanding standardized communication to roadside infrastructure
• Enabling scalable and vendor-independent connected mobility ecosystems

As connected mobility ecosystems continue to evolve, standardized interfaces provide the foundation for integrating traffic signal controllers, roadside equipment and future mobility technologies without replacing existing infrastructure.

For readers looking to explore the specification in more detail, the C-ITS Interface website provides the latest documentation, interface specifications and implementation resources supporting the SI Interface standard.

Download the free SI Interface whitepaper and discover how standardized interfaces enable interoperable and scalable connected mobility services.