The Physical Architecture forms a high-level structure around the processes and data flows in the Logical Architecture. The physical architecture defines the Physical Entities (Subsystems and Terminators) that make up an intelligent transportation system. It defines the Architecture Flows that connect the various Subsystems and Terminators into an integrated system.
The subsystems generally provide a rich set of capabilities, more than would be implemented at any one place or time. Equipment Packages break up the subsystems into deployment-sized pieces. The complete definition of the Physical Architecture is behind these entry points. By following the links, you can traverse between the physical architecture structure and the related process and data flow requirements in the logical architecture.