Planners and engineers may consider both conventional capacity improvements and intelligent transportation systems (ITS) to address transportation problems. Examples of ITS include freeway service patrols, advanced vehicle location systems, and certain elements of employee transit pass programs, each with various advantages. Details of a system to help planners and engineers make informed decisions about ITS deployment are provided. ITS Decision is designed to provide comprehensive information about state-of-the-art ITS technologies in a relevant form—the user can access desired information without sifting through irrelevant material. In addition, ITS Decision offers innovative tools to help users identify ITS appropriate for particular transportation problems. An expert system queries the user about specific conditions, diagnoses the problem, and suggests ITS remedies. The case-based reasoning tool lets users match historical cases that are most similar and see the effects. Given the still limited penetration of ITS into appropriate settings, the expert system and case-based reasoning tools are meant to stimulate greater deployment of promising technologies in localities that have not adopted such systems.