Road Restrictions

[stanleydao]

Hey Community,

I'm setting up a network dataset with some road restrictions, however i keep getting error messages when i try to find the closest facility between points.

For example: Warning: Location "Location 1" in "Incidents" is on a non-traversable network element position.

I think i understand the error, where the its saying that it can't use that road since it's a barrier/restriction. However, there are alternate routes that it could take (possibly of a longer path), but i do not understand why they aren't taking those routes.

Basically, how do i set this up so that it finds the closest facility by finding the shortest path while obeying the roads i set up as restriction seven if it means a longer path is taken vs. the one using the restricted path.

Thanks,
Stan

[RamB]

Please also take a look at 'tolerance distance' so that your position is picked appropriately.

regards

[MelindaMorang]

Hi Stanley.  When you run a network analysis, there are two things that have to happen with your network dataset.  First, the stops or facilities or origins or destinations you are using for your analysis have to be "located" on the network, meaning that their positions snap to the closest network edge.  Second, after their positions on the network are determined, the solver can solve a route between them or find the travel time or whatever.  The restrictions you've set up prevent or discourage the routes from using the restricted roads.  However, what's happening in your case is that the points are actually locating on a piece of the network that's restricted.  So, the closest network edge to your facility is a restricted edge.  The only way a route can be generated to that facility is to travel on a restricted edge.

Here's how to avoid this problem:
Open up your analysis layer properties and go to the Network Locations tab.  There's a checkbox at the bottom that says "Exclude restricted portions of the network".  Check that on and then reload your facilities/incidents/etc.  That will ensure that your points locate on the closest non-restricted network edge.