This paper describes the theoretical background and detailed structure of Navi-HEGS (Navigation system Human factors Evaluation and Guideline System) which has been developed for the human factors and HMI(Human-Machine Interface) researches for a CNS (Car Navigation System) and a digital map. Navi-HEGS is and integrated system that consists of a digital map UIMS(User Interface Management System), a CNS simulator, various evaluation tools, and a design guideline system. If Navi-HEGS is properly applied and utilized, it is possible to extract the substantial users requirements and preferences of a CNS and a digital map and then, these requirements can be simulated and evaluated with various human factors evaluation techniques. Applications of Navi-HEGS can improve the CNS usability, drivers safety and performance that directly affect the success of ITS(Intelligent Transport System). Also, results can be used as the basic data to establish the standards and design guidelines for the driver-centered CNS design.