Instead of this "messy map"... I don't think it is so difficult. It is hard
because of all the amount of information you need to describe correctly but
it is "easy". OSM can work with a 3D system, with in layers. Also you have
the incline tag,ele, exit_to, ref, ref:colour, destination: ,
Shuto Expressway system map, 24mb PDF.
http://www.shutoko.jp/%7E/media/pdf/customer/use/network/navimap/160701_map_big.pdf
I am wondering about proper motorway entrance-exit tagging when there seems to
be one tag that handles the intersection (highway=junction) and all the other
information
