Connecting the West V2X Accelerator Program

The Utah Department of Transportation (UDOT), in partnership with the Wyoming Department of Transportation (WYDOT) and Colorado Department of Transportation (CDOT), is leading the Connecting the West (CTW) Program to improve roadway safety, mobility, and system operations across state boundaries. This multi-state effort was selected by the Federal Highway Administration (FHWA) in 2024 as one of three national Vehicle-to-Everything (V2X) Accelerator sites.

Connecting the West brings together transportation agencies, transit providers, and technology partners to improve how roadway and traffic information is communicated directly to vehicles and travelers. At the core of the effort is Vehicle-to-Everything (V2X) technology. This technology allows infrastructure, such as traffic signals and roadside equipment, to share safety and mobility information with vehicles, mobile applications, and traffic management systems, ultimately supporting safer intersections, more reliable corridor operations, and improved responses to weather events, incidents, and vulnerable road users.

By improving interoperability between systems, the program enables connected vehicle applications to function seamlessly as travelers move between Utah, Wyoming, and Colorado.

Planning, System Architecture, and Data Exchange

A key step in the CTW Program is the development of a Concept of Operations (ConOps), which defines shared challenges, project goals, stakeholder needs, and how the connected transportation system will function from a user perspective. The program follows an incremental development process that moves from planning into deployment and operations. Existing connected vehicle systems within each state are expanded, while new capabilities focused on interoperability and secure data exchange are added. This approach allows proven technologies to be enhanced rather than replaced, reducing risk and supporting long-term sustainability.

Trihydro supported the ConOps by proposing a scalable approach to data exchange and system integration. The CTW Program adopted Trihydro’s SDX platform as the regional hub for sharing Connected Vehicle Traveler Information Messages (TIMs) between participating states and third-party traveler information providers, including Waze, Google, TomTom, and others. Each state deposits TIMs into the SDX, where they can be redistributed to roadside units (RSUs) near state borders to support seamless cross-border traveler information and connected vehicle operations.

In addition to supporting TIM distribution, Trihydro expanded the SDX platform through development of the SDX Hub, a new capability focused on real-time interstate coordination and event sharing. The SDX Hub uses the emerging next-generation Traffic Management Data Dictionary (ngTMDD) standard for center-to-center communications, enabling agencies to exchange roadway events, operational information, and situational awareness data in near real time. As an evolution of TMDD, ngTMDD is expected to play a significant role in advancing future transportation system interoperability and regional coordination.

Connected Intersections and Corridors

CTW focuses on deploying connected vehicle technology in areas where safety and mobility challenges are most significant. At signalized intersections, roadside equipment enables traffic signals to communicate timing and status information to approaching vehicles. This information can be used to support safety applications that warn drivers of potential red‑light violations or other intersection hazards.

Along interstate and rural corridors, connected roadway infrastructure provides travelers with timely information about weather conditions, incidents, work zones, and traffic disruptions. By sharing consistent messages through both roadside systems and cellular networks, agencies can reach a broader range of travelers and improve situational awareness across long-distance routes.

Vulnerable Road User and Fleet Operations Support

The CTW Program also addresses safety for vulnerable road users, such as pedestrians and cyclists, by expanding systems that detect their presence at intersections and alert drivers. This information helps reduce conflicts and improve driver awareness at locations where crashes involving vulnerable road users are more likely to occur.

Additionally, connected vehicle technology supports improved operations for agency fleets, including transit vehicles, emergency responders, and snowplows. By reducing unnecessary stops and delays at intersections, these systems help agencies improve response times, maintain schedules, and reduce fuel use and emissions, particularly during winter operations and emergency events.

Interoperability and Secure Communications

Achieving interoperability across agencies and state boundaries is a primary objective of the CTW Program. A key component of this effort is the standardization of Traveler Information Messages (TIMs), which are defined under the SAE J2735 messaging framework. TIMs deliver roadway information directly to motorists, including construction activity, lane closures, weather hazards, and incident locations.

While TIMs provide a structured format, the content of these messages has historically varied between agencies. Through CTW, Trihydro led a project group responsible for defining a consistent set of TIMs for common roadway conditions. This effort established standardized message content and formatting, ensuring that vehicles receive uniform, clearly interpretable information regardless of location.

This standardization can be compared to traditional roadway signage. Just as physical signs maintain consistent meaning across states, standardized digital messages allow connected systems to communicate roadway conditions in a clear and predictable manner. Unlike static signage, however, TIMs can convey detailed, real-time information that adapts to changing conditions.

The standardized TIM framework developed through CTW is considered a basis for broader adoption, supporting the continued evolution of a nationwide digital transportation infrastructure.

Secure Communications and System Integrity

In addition to interoperability, CTW emphasizes secure communications and data integrity. Each participating state operates secure systems to authenticate and protect messages transmitted to vehicles. The program focuses on ensuring these systems function cohesively, allowing safety and mobility information to be exchanged reliably while maintaining appropriate security controls.

Outcomes

Through Connecting the West, participating agencies are establishing a coordinated approach to connected vehicle deployment across Utah, Wyoming, and Colorado. By expanding existing systems and adding new interoperable capabilities, the program creates a foundation for safer intersections, more reliable corridor operations, and improved communication with travelers.

The program supports earlier awareness of roadway hazards, better protection for vulnerable road users, and improved efficiency for transit and maintenance fleets. At a broader level, CTW helps advance nationwide connected vehicle deployment by demonstrating how agencies can work together to overcome interoperability challenges and scale emerging transportation technologies.