Road - woven-planet/opensafety-mbse GitHub Wiki

In general parlance “road” can mean many things. It is largely because of the familiarity we all have with this term that makes it difficult to define precisely. For example, is an onramp a distinct road? Is a driveway? Are two adjacent and opposite flows of traffic a single road or two? Many definitions are possible, which is why we take our unique perspective into account.

In the Vehicle Environment domain, we take the perspective of the Ego Vehicle as it traverses and interacts with its immediate environment. Much of the time an Ego Vehicle will travel along some rectangular paved or otherwise treated surface in the long direction. The long direction of this rectangle will coincide with the Ego Vehicle heading when it is being traveled. Otherwise, the shorter width will be encountered typically at a right angle, but certainly from many other possible crossing, forking or merging angles.

Roads are typically named somehow. There may be a local designation such as “El Camino Real” or a more official, global name such as “CA-82”. These designations typically include both flows of traffic. So it seems natural to assume that a road may encompass either a unidirectional or bidirectional or possibly undirected flow of traffic. Most importantly, we can separate the concept of a flow of traffic in some direction from a road’s physical extent.

Whether or not it is immediately observable, we can say that a road is always bounded by two edges running lengthwise. One of the traverse edges begins on one detection horizon and on the roughly opposite horizon with respect to the Ego Vehicle.

Identifiers

1. ID

Attributes

ID

The Ego Vehicle may or may not be aware of the map name of the Road it is currently driving. So we use an arbitrary number to distinguish between “this road” and “that road over there”. But we always try to determine the correct Road Map Specification given our available navigational and sensory facilities.

Type: Road ID, based on Nominal type