Calculating total poyline length without double counting lengths in areas with more than one line segment

[MelC]

I am working on a project in ArcGIS Pro where I am trying to calculate total route length (polylines), but in a lot of areas I have more than one line segment. For example, if an area is 1 mile long but there are three line segments following that whole mile, I need to calculate only 1 mile, not 3 miles. The polylines are almost never overlapping so dissolving won't work. The area is quite large, sometimes the lines are 10 meters apart, sometimes only 3 meters, some run perpendicular to each other, while others run parallel. I have tried a couple of different approaches, none of which I am satisfied with. I was looking for some guidance from the community! Thank you in advance.

[DanPatterson]

a picture might help, but first thoughts are

clip the polylines by your areas featureclass.  This should give you the polylines or segments of polylines in each area with their lengths.

summarize within  Summarize Within (Analysis)—ArcGIS Pro | Documentation

or spatial join  Add Spatial Join (Data Management)—ArcGIS Pro | Documentation

 of the polylines to the polygons should

allow you to get the statistics for polyines within each polygon