R80 - woven-planet/opensafety-mbse GitHub Wiki
R80 / M:Mc-1
Interface Crosswalk spans zero, one or many Intersection Interface
Intersection Interface is spanned by zero, one or many Interface Crosswalk
In a simple Intersection there are often Crosswalks lined up with each of the Intersection Interfaces. These are Intersection Crosswalks. When there are no intermediate Median or Island Crosswalk Accesses, we see that a single Intersection Crosswalk spans a single Intersection Interface, as is the case with Intersection Crosswalks X4 and X3 in the example below.
With at least one intermediate Crosswalk Access present, as is the case with X1 and X2 in the example above, multiple Intersection Crosswalks can span the same Intersection Interface.
In an unusual, but possible scenario as shown in the next example below, Intersection Crosswalk X4 is spanning multiple Intersection Interfaces, namely I1-RS3 and I1-RS2.
Finally, it is not unusual to block off certain Intersection Interfaces such that pedestrians are not permitted to cross at all. In such a case we have an Intersection Interface with no crosswalk at all.
Formalization
Interface Crosswalk Span.Crosswalk -> Crosswalk.ID
Interface Crosswalk Span.(Road segment, Intersection) ->
Intersection Interface.(Road segment, Intersection)