The Traffic Operations and Safety (TOPS) Laboratory at the University of Wisconsin-Madison, in partnership with the Wisconsin Department of Transportation (WisDOT), has started development of a data management system (WisTransPortal) to facilitate continuous collection and archiving of Intelligent Transportation Systems (ITS) data in Wisconsin. The basic objective of the WisTransPortal project is to develop capabilities for a statewide ITS data hub to support multiple applications in traffic operations and safety. Those capabilities include integration, management, analysis, and dissemination of real-time and historical ITS / traffic operations data through a centralized database and communications infrastructure. The data archiving component of the WisTransPortal consists of a collection of automated services that connect to various WisDOT and other ITS data sources and prepare the data for archiving in a common relational database. The current development phase of WisTransPortal is focused primarily on replicating and integrating five existing WisDOT and regional data sources: traffic detector data, lane and ramp closure data, traffic incident data, historical crash reports, and road weather information. The design of the WisTransPortal system is based on a distributed model that separates logical software components such as Web presentation, application logic, and data management components. The benefit of this design is in the ability to support the development of a wide range of user applications and to allow, at the same time, for gradual improvements to the underlying database model. In addition to the core archiving and data clearinghouse functions of the WisTransPortal, the system is designed to provide a platform for the development of high-level software modules to support existing and new WisDOT transportation operations applications. In this paper, we describe the ITS architecture and technical organization of the WisTransPortal. The key components of the system include a direct link from the WisTransPortal system to the WisDOT fiber optic network, data management in Oracle Database 10g, and web-application development based on Java Enterprise (J2EE) technologies. An important technology direction of the project is the use of Open Source Java and J2EE frameworks such as Struts and Hibernate to facilitate robust code development, multi-layered design, and portability.