The Physical Viewpoint represents physical elements that operate in the mobile environment, the field and the back office, where connections between elements and interactions with the external environment are considered. The Physical Viewpoint deals with the composition of these physical objects (including application servers, data stores, network components, mobile and non-mobile transportation elements, and wired and wireless links), their physical connections and interactions, and the allocation of functionality to those elements. For HARTS the focus is on the connections between these physical objects.
Each ITS Service Package includes the physical objects that participate in providing and accomplishing that ITS service. A service package diagram such as shown below for Transit Signal Priority includes hyperlinked content. Currently this allows the user to explore the communications standards needed to support interactions between objects. Clicking on an information flow will link the user to the communications view of the flow clicked.
Note that currently, only the flow hyperlinks are active. Other objects on the screen may receive object detail pages in the future.
The following figure explains the diagrammatic conventions used to document the Physical View in service package diagrams as provided on this Website.
The table below provides definitions for the terms identified in the diagram above.
|Center||An entity that provides application, management, administrative, and support functions from a fixed location not in proximity to the road network. The terms "back office" and "center" are used interchangeably.|
|Field||An entity located near or along the transportation network which performs surveillance (e.g. traffic detectors, cameras), traffic control (e.g. signal controllers), information provision (e.g. Dynamic Message Signs (DMS)), local transaction (e.g., tolling, parking) functions, and/or wireless communication services between mobile elements and fixed infrastructure. Typically, their operation is governed by management functions running in Centers.|
|Support||An entity, typically from a fixed location, that provides support services for one or more other objects.|
|Traveler||Equipment used by travelers to access transportation services pre-trip and en-route. This includes equipment that are owned and operated by the traveler as well as equipment that are owned by transportation and information providers.|
|Vehicle||Vehicle related elements onboard vehicles. Vehicle physical objects include general driver information and safety systems applicable to all vehicle types.|