n
The UCF Driving Simulator has evolved since the late 1990's into a midrange simulator with the potential to conduct research in transportation, human factors and real-time simulation. The most serious limitation relates to the absence of vehicular traffic in the visual data base. Without moving cars, the driver is immersed in a sterile driving environment. Interaction with other vehicles is essential for training or certification of new drivers. It is equally important for investigating traffic operations on freeways and at signalized intersections. In 1999, a multi-year project was initiated to introduce autonomous vehicles for real-time interaction with the simulator vehicle. During the first year, a traffic network consisting of several one and two-way roads, an outer loop and intersections with traffic control devices was created. It is completely defined in terms of a set of nodes and links. Traffic generation software was written for execution on a PC platform to calculate positions and headings of simulated vehicles with respect to the link/node coordinate system of the network. Link/node vehicle coordinates, of the link number, distance along the link from the upstream node, and heading are transformed in the PC to x,y and heading values in the coordinate system of the 3D modeling software to create the visual database. This transformation guarantees the vehicles will be properly registered with respect to the centerlines of the roads. Presently, the vehicles are either randomly advanced along the links each frame or deterministically placed for purposes of creating specific scenarios. In the future, microscopic traffic models will be employed to produce intelligent movements of the simulated vehicles. The transformed coordinates are communicated over a network to the simulation control program running in the simulator host computer. The PC traffic generation frame rate (1 Hz) is slower than the 30 Hz frame rates of the vehicle dynamics model and Image Generator, necessitating interpolation of the PC vehicle coordinates to assure smooth rendering of the simulated vehicles.