List of Logical Data Flow Diagrams


Figure 1 Context Diagram
The Context Diagram shows the connections between the System (or ITS) and the Terminators. Each Terminator is linked to the System by a terminator Data Flow. Those shown in the Context Diagram are the Top Level, or Context Terminator Data Flows. Each of them will have one or more component Medium and Low Level Terminator Data Flows that link to the Functions.
Figure 2 Functional Area Diagram (DFD0)
The interfaces between the eight Functional Areas are provided through the data that flows between them. These are shown in the highest-level Data Flow Diagram, called DFD0. It also shows the Medium Level Terminator data flows. These are components of the data flows shown in the Context Diagram. There is one Medium Level Terminator data flow for each connection between a Terminator and a Functional Area. Note that not all Functional Areas are connected to all Terminators.

Definition of Logical Data Flow Diagram

The Logical Data Flow Diagrams show how the functionality for each Area is divided into High and Low Level Functions. They also show how these Functions are linked to each other and to the terminators through Data Flows. When used by several Functions, Data Stores are also shown, together with the Data Flows linking them to the Functions.The DFD's are all numbered in a hierarchical sequence and named. The numbering scheme uses the Area number as the first digit. The second and subsequent digits are taken from the Function that they are describing - see the previous section on Functions. The DFD names are direct copies of either the Area name or the name of the Function that they show.

1. Provide Electronic Payment Facilities2. Provide Safety and Emergency Facilities3. Manage Traffic4. Manage Public Transport Operations5. Provide Advanced Driver Assistance Systems6. Provide Traveller Journey Assistance7. Provide Support for Law Enforcement8. Manage Freight and Fleet Operations9. Provide Archive