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R21 / M:M-1

Lane Division is inside/outside adjacent to one or many Lane Division

A Lane Division is defined as the space between two adjacent Lane Divisions. This suggests a 1:1 relationship or inner-outer pairing of Lane Divisions. But if you look at the full length of a Road Segment (see below) it is apparent that the same Lane Division may pair with different Lane Divisions as the lanes are reconfigured.

images/road-subsystem/R21-10.png

For any pair of adjacent Lane Divisions on a Road Segment, one division will be toward the inside (nearest the Median) and the other toward the outside (nearest the shoulder). See Lane.Inside division description for more about the use of inside/outside directions.

The innermost Lane Division will not be outside of any other Lane Division and the outermost Lane Division will not be inside any Land Division, hence the conditionality (zero multiplicity case).

Formalization

Lane.(Inside division, Road segment) -> Lane Division.(ID, Road segment)
Lane.(Outside division, Road segment) -> Lane Division.(ID, Road segment)