A multi-agent Advanced Traffic Management and Information Systems (ATMIS) framework is proposed. Multiple private traffic information service providers cooperate or compete with each other in the ATIS market which most existing studies look at as a one-supplier system, mostly run by a public agency. Subscribers to private information services become probe vehicles and report traffic data as well as travel diaries (individual path-based data) to the private vendors. A Traffic Management Center (TMC), i.e., public agency optimizes network-wide traffic signal controls, for which a dynamic traffic optimization model (or algorithm) is developed in an integrated fashion at the network level on the basis of path- based data with traffic information supply and route guidance. In the framework, the private companies provide the path-based data used in the traffic signal optimization model to the public agency and in return get the optimized traffic signal control plans which are essential in predicting future traffic conditions. The study is simulation-based, as the path-based data collection systems are only expected in the near-future. The study results are expected to develop insights on the benefits from such cooperative public-private operations and provide the impetus for private and public investment in the necessary data collection infrastructure.