Time dependent transportation network models

Network data models are frequently used as a mechanism to solve wide range of problems typical for the GIS applications and transportation planning in particular. They do this by modelling the two most important aspects of such systems: the connectivity and the attribution. For a long time the attributes like the travel time, associated with a transportation network model have been considered static. With the advancement of the technology data vendors now have the capability to capture more accurate information about the speeds of streets at different times of the day and provide this data to customers. The network attributes are not static anymore but associated with a particular time instance (e.g time-dependent). In this paper we describe our time dependent network model tailored towards the need of transportation network modelling. Our solution is based on the existing database functionality (tables, joins, sorting algorithms) provided by a standard relational DBMS and has been implemented and tested and currently being shipped as a part of the ESRI ArcGIS 10.1 platform and all subsequent releases.