One-way streets can be modeled with geometric networks using weights, weight filters, and weight values of -1.
- In ArcCatalog, add two long integer fields to the edge feature class that represents streets. Call one field FromTo and the other ToFrom. Try setting the field's precision to 10.
- In ArcCatalog, create the geometric network. When prompted by the wizard to assign weights to your network, click Yes to add weights.
Weights can only be added at the time the network is created. If weights must be added, the existing network must be deleted and reestablished in order to gain access to the weight creation dialog.
- Create two integer weights, FromToWeight and ToFromWeight. Associate FromToWeight with the edge field FromTo. Associate ToFromWeight with the edge field ToFrom. Continue with the wizard to complete the creation of the geometric network.
See the manual Building a Geodatabase for details on adding weights to Geometric Networks.
- Open ArcMap, add the geometric network to the ArcMap session, and Start Editing the edge feature class for the streets.
If the data is stored in an ArcSDE database, the geometric network's feature dataset must be registered as versioned before editing.
- Change the line symbol for the street edges so that you can see the direction in which these lines were digitized. This can be done by clicking the line symbol for the street edges in the ArcMap TOC. Then click Properties > Type: Cartographic Line Symbol > Line Properties tab > Line Decorations: click the radio button for the arrow that points to the right only > Click OK > Click OK.
- Select all one-way street edges whose digitized direction is the same as the street's travel direction. Then click the Attributes button and set the ToFrom field to a value of -1.
- Select all one-way street edges whose digitized direction is opposite the street's travel direction. Then click the Attributes button and set the FromTo field to -1. Save these edits and stop editing.
- Click View > Toolbars > Utility Network Analyst. On this toolbar click Analysis > Options.
- Click the Weight Filter tab. Set the Edge weight filter for From-to weight to FromToWeight and the To-from weight to ToFromWeight.
- Set the Weight range to -1 and click the "Not" check box on.
- Set the Trace Task to Find Path, set the desired flags and barriers, and click the Solve button.