What's New in 9.3.1
Take a look at the new features and tools you can use with ArcGIS Desktop 9.3.1
ArcGIS Network Analyst uses an advanced Network Data Model that allows the use of realistic datasets encompassing multiple attributes such as cost, restriction, and hierarchy. You can define various cost attributes, such as distance, time, and visibility, according to their analysis requirements.
Features of the Network Data Model include
Multimodal network support incorporates an advanced connectivity model that can represent complex scenarios such as multimodal transportation networks.