Transportation is one of the most dynamic fields of industry, highly related to the development of the information and communication systems. The transportation system environment is regulated by economic, technological, and political issues that, together, focus on the improvement of the services provided by the transportation infrastructure. The ultimate goal is the enhancement in the performance and safety of the transportation system, that leads to the concept of the Intelligent Transportation System ( ITS ). The Ohio State Center for Mapping has performed research in the area of the Advanced Vehicle Control and Safety systems, that are defined within the national ITS architecture. During 1994-1995, a real-time Global Positioning System (GPS) positioning and moving map display system was developed as a cooperative effort between the Center for Mapping and the Traffic and Transportation Laboratory of the Department of Civil Engineering, The Ohio State University. The real-time GPS positioning and moving map display system consists of two personal computers, two modems, one GPS receiver, one cellular phone, and software to access and update the Geographic Information Systems (GIS) database and communicate between the GPS base station and the rover unit. The GPS receiver, the laptop computer, and the cellular phone are installed in the moving vehicle. The base station, located at the Transportation Lab, houses the other computer and the modem. The GPS positions of the moving vehicle are dynamically displayed on a moving map display inside the vehicle and at a central control station, using a cellular link for real-time communication. This system was demonstrated to the Congestion Management Committee for the city of Columbus, and attracted lots of interest.

As a next step towards the development of the Intelligent Transportation System (ITS), a GPS/GIS real-time curve warning system is being developed at the Center for Mapping, using the real-time GPS positioning and tracking system described above. This system uses a digital map database (GIS), real-time GPS positioning, and vehicle speed information to warn the driver of road speed limitations. The system will automatically define the speed limit for the road segments based on their curvatures. It will consist of a GPS receiver connected to a laptop computer. The laptop computer will contain a digital map database (GIS) for the area of interest. This database, together with the real-time GPS positions and the vehicle's speed information, will provide the basic components needed for the implementation of the curve warning system. A digital map of the Clark County transportation network is used for the system's prototype development. This is an accurate and up-to-date map of the county developed at CFM in 1994, using integrated GPS and Dead Reckoning (DR) positioning system, implemented in the CFM's GPSVanTM