1.1.4 - Display and Output Traffic Data DFD

This DFD shows the processes that make up the Display and Output Traffic Data facility within the Manage Traffic function. These processes provide the interfaces through which stored traffic data can be provided to other ITS functions and the media.

The key points about the facility are as follows:

Access to current, historic and predictive model data provided for traffic operations personnel and for archiving;
Media can access data under the control of traffic operations personnel;
Other ITS functions and Manage Traffic facilities provided with access to the data on request;
Output can be presented against the background of digitized map data.

There are five processes in this DFD:
a) Retrieve Traffic Data (1.1.4.1)
b) Provide Traffic Operations Personnel Traffic Data Interface (1.1.4.2)
c) Provide Direct Media Traffic Data Interface (1.1.4.3)
d) Update Traffic Display Map Data (1.1.4.4)
e) Manage Traffic Archive Data (1.1.4.5)

Process (a) is responsible for retrieving the requested data from the stores of current, long term (historic) and predictive model data. It receives requests from process (b) which provides the traffic operations personnel interface. This process acts as the interface between processes (c) and (a). It enables the traffic operations personnel to control the access that the media and other ITS functions have to the stored data. It also controls the output of data to systems, e.g. highway advisory radio (HAR), dynamic message signs (DMS), or flashing lights that direct drivers to tune their radios to a particular frequency to receive traffic information. The data collected in process (a) is then sent to process (e) for archiving.

The process (b), (c) and (e) depend on the process (a) for data and can only function as a group. It is possible for the outputs provided by the processes (b) and (c) to appear without the digitized map data produced by the fourth process. For process (b) an example might be video image data provided by traffic surveillance cameras.

DFD: 1.1.4 - Display and Output Traffic Data

Parent DFD: 1.1 - Provide Traffic Surveillance

PSpecs in this DFD: