TMDD Standard

The Connected Corridors system architecture uses the TMDD (Traffic Management Data Dictionary) standard for data exchange between the core system and external software components, such as Traffic Control Systems, Arterial Sign Management Systems, and the Caltrans’ ATMS. This includes the data hub, Decision Support System, Corridor Management System (CMS), Traffic Control Systems (TCS), sign control systems, and other systems. The interfaces are what enable communications between the equipment in the field, the traffic management centers and stakeholder agencies, and the ICM core system. Without information flowing between these systems, response plans cannot be generated or implemented efficiently. To fill these communication requirements, the CC team is working with three companies to provide TCS interfaces and three other companies to provide the ICM core functions of user interfaces, mapping, and response plan management.

“The Traffic Management Data Dictionary (TMDD) Standards were developed to support center-to-center communications as part of the regional deployment of ITS in order for centers to cooperate in the management of a corridor, arterial, incident mitigation, event management, etc. Hence the TMDD provides the dialogs, message sets, data frames, and data elements to manage the shared use of these devices and the regional sharing of data and incident management responsibility.” – Institute of Transportation Engineers (ITE)

As a part of their participation, all of the companies have agreed to modify their interface and its functionality using the standard TMDD format to meet the needs of the CC Project. A vendor will also be selected for the sign technologies being implemented in the corridor. PATH will oversee the vendors and ensure the various interfaces match the system requirements as developed by Caltrans and the stakeholders. The goal will be for PATH to certify each interface verifying its ability to be readily integrated into CC's core system.

Once they are tested and validated for the I-210 Project, all of these products will then be available statewide, with the knowledge that the interfaces work using a TMDD standard. Caltrans Districts and other agencies will be able to select from a list of vendors with ready to go systems, rather than starting from scratch. Specifications and detailed requirements for the Project and its supporting systems will also be available. This will greatly reduce the risk and costs associated with implementing ICM and pave the way for better systems and technologies to be accessed across California and beyond.