Is there a way of attaching connectivity data to nodes in a network topology? For example, a bridge where two roads cross might be represented by four polylines A, B, C, D with endpoints coinciding where the bridge is. How would you represent the fact that A joins C and B joins D but A does not join B/D and B does not join A/C?
First of all you needn't create nodes, where the traffic streams are not crossed.
HERE is a video showing two choices running of Network Analises: A - with a bridge or an overpass> B - with a road's intersection at the same level.