Creating shortest route using line-segment layer as network locations?

Question

I'm currently using Arc10.2.1 and new to the network analyst tool. I'm trying to create a truck route that begins at one location on a county street grid and ends up in the same place, following a feature class of line segments of guard rails throughout the whole county - we need to create the most efficient path possible.

I understand the concept of network analysis objects and network attributes, but need to use these line segments as such. However, the only line-based network analysis objects that can be defined as network locations are line and polygon barriers. I was successful in using my guardrail feature class to create the shortest route that avoids each guardrail, but not one that follows it. When I attempt to use the segments as "stop" input features it tells me that it is an incorrect input.

I thought of creating centroids from each segment to use as stops, but that provides little information for the truck drivers to know exactly where along the roadway the guardrails are located.

This seems like it would be a common problem, yet I haven't been able to find anything on it.

Answer 1

You cannot use lines as stop inputs for a network analysis. The only way you could possibly use the lines is to set them as barriers but give them a negative value (ie, rather than adding time, they take time away) such that they attract the route rather than avoid it. You still have to set stops though.

If centroids are not sufficient, it would be suggested to create points out of the start and ends of the guardrail sections. Unless the analysis is set using a curb approach restriction, you won't be able to define which point is the start vs end. If you do use a curb approach restriction, then you know based on direction of travel which will be the start and which the end. U-turn restrictions, etc, will also play a role. Your vehicle routing problem will need to allow reordering of stops for greatest efficiency.