I have noticed, in the tutorial arcgis, that all road split on the intersections.
I want to know, must split road on the intersections for network analyst?
Personally, I think it's at least better practice if not best practice to model your roads to be split at intersections. You have an option in NA to use coincident vertices for connectivity. But think about it; you could and often times would end up with connectivity between a limited access highway and an over passing or under passing surface street. Have fun explaining to the boss when you depict a route that jumps or falls 50 feet from one road to another....
