DEFINING DIRECTIONS
Your network is still a free-flow network without any directional restrictions. In order to set directions, you need to add a field called oneway to the road theme attribute table. Use same procedure as above.
To set a direction, the field oneway must contain the value ft (from-to) or tf (to-from). ToFrom or FromTo here correspond to the topological ordering as mentioned previously.
Use the table edit procedures as outlined above to create the oneway field, Click the Edit icon , then click the cell you want to edit, enter your value, hit Enter. Remember to save your edits, Table > Stop Editing, when done.
Make sure that on/off -ramps and freeway lanes are modeled with correct directions. This can be a tedious process, but nevertheless part of any QA/QC. Unless you want to spend endless hours in the lab, assume that everything is correct, then solve some routing in the vicinity of freeways and visually check that the route takes the lane/ramp it is supposed to. Edit as you go along.
If you want to restrict travel totally, enter n in the oneway field.