Within scenario management, Visum makes sure that all network objects of a project have unique IDs. They are managed in the database file. This way, there are no network objects with the same ID in your modifications.
When you add a new network object, Visum automatically suggests the next free ID for the project. This is why Visum automatically activates the option Conflict avoidance for numerical keys, when reading in additional network data or modification files. Visum then automatically determines the next free ID per network object type and selects the corresponding offset.
In some cases, however, it might be useful to change these settings. For instance, you might want to compare the same stop at different locations or with different properties, in several scenarios. In this case, create a stop with the same ID in several modifications. The modifications then exclude each other, but they can be used in several scenarios. When comparing these scenarios, you can compare the stop attributes (and the corresponding lines), as they have the same ID.
