In April 1998, the body responsible for defining ITS User Services took the step to initiate an ADUS. That process is likely to be completed while CHART II is being implemented. A report released by U.S. DOT in April 1998, called ITS as a Data Resource: Preliminary Requirements for a User Service, identifies a set of system requirements as well as a set of implementation issues. The following is a paraphrasing of 16 guiding principles presented in Chapter 4, Basic Requirements, of that report. These principles should serve as the basis for developing a more detailed set of requirements for consistency with the National ITS Architecture.

• Use ITS data flows to provide useful information for stakeholder applications,
• Be based on existing and future data flows,
• Transition from a decentralized to a more centralized structure,
• Provide for data processing, storage, and retrieval systems,
• Provide for data flows from subsequent systems,
• Functions of the existing Planning Subsystem should be integrated into the systems to support the Archived Data user Service,
• Support for user specified data quality control and editing procedures, including a record in the "metadata" portion of the data dictionary identified below,
• Ability to perform the data processing functions of: (1) store data in the same structure as received from the field, (2) accommodate levels of aggregation of the data flows, and (3) sample raw data flows for permanent storage in accordance with use specifications,
• Contain "metadata" on each data element, including items such as, basic data dictionary attributes, the source of the data, the conditions under which the data was collected, … and the results of any data editing/quality control,
• Raw data from incoming flows should be capable of being stored on-line for a period of time specified by individual system designs,
• Data producers should have the ability to review, edit, and flag data prior to the data being permanently archived,
• Work with all applicable standards and protocols such as NTCIP, TCIP and others,
• Preclude the possibility of identifying or tracking individual citizens and should follow the ITS Privacy Principles developed by ITS America,
• Systems supporting ADUS should accommodate at a minimum the nearly 50 data elements, or record types and associated structures, listed in table 4.1 of that report,
• Be capable to archive transformed data, as defined by local option, and
• Be compatible with and use the various ITS data dictionaries now being developed, such as the Advanced Traffic Management Data Dictionary (TMDD), and others.