On Road Ego Vehicle - woven-planet/opensafety-mbse GitHub Wiki

Here we distinguish an Ego Vehicle driving on a Road as distinct from an off road Ego Vehicle which might be in a parking garage or driveway.

While it is certainly true that many vehicle behaviors apply equally well on the road or in a parking lot, there are many which vary. For example, you cannot perform a lane change in a parking lot. There are no shared bike lanes, shoulders, or parking lanes (as they are defined in the Road Subsystem anyway). You do not encounter a signalized intersection in a parking lot. But wait, could you? It certainly is not difficult to imagine such an arrangement, but it would be a rare exception. And, in such an exception, we might find a way to define some kind of road equivalent internal to such an elaborate parking lot.

Until we model parking the parking lot environment and clarify what’s in and out, it is safest to assume that these are completely different environments, each with their own specific rules and geometries. By singling out an Ego Vehicle on Road, we emphasize that this is the only environment that we are defining and that, outside this environment, our driving environment assumptions do not necessarily apply.

1. Ego
2. Road

Since there can exist at most one instance of Ego Vehicle on Road, it stands to reason that either attribute, given a value, will yield exactly zero or one instance.

(No non-referential attributes)