Introduction Design and Scope of the IDAS Model Definitions IDAS ITS Components IDAS Analysis Hierarchy IDAS Deployment Hierarchy Other Definitions Computer Hardware and Software Requirements Obtaining a Copy of IDAS and User Support   Contact Webmaster IDAS is intended to provide a tool for comparing the performance of several ITS options against "control" alternatives. The analysis hierarchy for IDAS consists of projects, alternatives, and ITS options, as defined below. The Analysis Hierarchy graphic provides an example of how the analysis hierarchy can be used in evaluating scenarios as part of a transportation planning study. Project - A project is the highest level of the analysis hierarchy. A project is generally defined by a common set of overall travel demand determinants (e.g., socioeconomic data, model centroid zone structure, etc.) and by a common year of analysis. A project may consist of one or more alternative(s). A project may be defined, saved and later retrieved. IDAS allows only one open project at a time. Alternative - An alternative is generally defined by a common set of output from a single travel demand model run. Any traditional infrastructure capacity improvements, such as additional highway lanes, freeway ramps, or transit lines, are typically represented in the travel demand model output. ITS improvements will be added to the alternative to create different ITS options. Control Alternative - Once the travel demand model data have been input into IDAS, a control alternative is created which serves as the baseline for building and comparing ITS options. The control alternative does not contain any ITS components other than those previously deployed in the network. Each alternative has one control alternative. The control alternative is subjected to analysis procedures identical to those applied to the ITS option, thus providing for meaningful comparison of results. ITS Option - An ITS option is an ITS deployment alternative, which is to be compared against other options, as well as to the control alternative. An ITS option is defined by one or more ITS improvements. IDAS calculates the impacts and associated benefits, and the costs of the ITS option, in the IDAS benefits and cost modules, and compares these estimates to the control alternative in the IDAS alternatives comparison module. Many ITS options can exist within an alternative.