It defines system components, key functions and organizations involved in developing an architecture as well as the type of information to be shared between organizations and parts of the system. It s unlikely that any single metro area or state would plan to implement the entire National ITS Architecture. Therefore the Rule and Policy require that the National ITS Architecture be used to develop a framework for how ITS may be implemented locally. This is referred to as a regional ITS architecture. A regional ITS architecture is a local implementation, or subset of the National ITS Architecture, developed with local needs in mind.
Local participants define the region based on needs for information sharing and coordination.
The region can be a metropolitan, Statewide, multi-State, corridor or service area. If a region has not yet deployed an ITS project, a regional ITS architecture must be developed within four years after its first ITS project deployment. Modifications to existing systems in order to conform with the National ITS Architecture are not required by the Rule and Policy. It s anticipated over time, however, that regional ITS architectures would call for changes to legacy systems in order to support local desires for integration. Until a regional ITS architecture is in place, all major ITS projects must have a poject level architecture to ensure proper consideration of regional integration.