Intelligent Vehicle Highway System (IVHS) represents the application of information technology to improve the effectiveness of the existing road transportation system resulting in increased safety and better traffic management [1,2]. In-Vehicle Safety Advisory and Warning System (IVSAWS) Program is a Federal Highway Admisistration project to develop a system that provides drivers with advance notification of roadway hazards. IVSAWS units will provide supplemental warnings in order to ameliorate hazardous scenarios (e.g., railroad grade crossings, slow moving vehicles) which are particularly hazardous and have remained hazardous despite traditional crash reduction techniques such as additional mechanical signing.Program aspects include hazard scenario identification, system architecture design, driver alert warning subsystem design, communication subsystem design, and proof of concept field testing. Highway safety data has been examined to determine which scenarios IVSAWS could benefit. Human factors issues and system cost goals determined system architecture. This paper discusses system architecture design to date. Development and evaluation of the driver interface is proceeding using simulators at General Motors Simulation Lab.