Automated Highway System Tool Interface Format

Extended Abstract The Automated Highway Systems (AHS) project at UC-Berkeley is part of a comprehensive program initiated by the U.S. government under the Intermodal Surface Transportation EEciency Act of 1991 to improve safety and reduce congestion in the surface transportation system. UC-Berkeley's PATH program is a partner in the nine-member National AHS Consortium (NAHSC)heed Martin and Parsons Brinckerhoo. The consortium is funded in part by the Department of Transportation and it is responsible for designing, evaluating and demonstrating a prototype AHS. 1 The NAHSC is responsible for identifying several AHS design concepts, evaluating and selecting six of these for detailed study, specifying, evaluating and selecting three AHS designs from these six concepts, and nally synthesizing a single AHS design from the three. Diierent categories of tools are required to accomplish these tasks. Signiicant amongst these are simulation tools for system-level AHS simulation, technical analysis tools for safety, highway productivity, comfort, environmental impact and cost and design tools for vehicle, highway, sensor, communication and other technologies. We propose a common interface format, the Automated Highway System Tool Interface Format (AHS TIF) 1] , for these design and evaluation tools. Such standardization facilitates objective comparison of diierent AHS designs, streamlines tool development and integration and promotes meaningful communication among concept designers, tool developers and concept evaluators. The AHS TIF is a programming language for specifying AHS designs and scenarios. Design speciications describe the elements of an AHS such as vehicles, highways, sensors, actuators, communication devices and controllers. Scenarios describe highway conngurations and traac patterns. The AHS TIF consists of two parts: a hybrid systems-based modeling framework with powerful high-level abstractions and a library of component types that customize the framework to the AHS domain. The framework supports input-output and state-space modeling and static and dynamic environment modeling. We model each component type uniformly by describing the component as an input-output system. The inputs and outputs are related by the component's dynamical behavior which is set in continuous time. All components of a given type have the same structural and behavioral description; they diier only in the values of their corresponding input, output and state variables. The dynamical behavior of a component is deened by equations on its state, input and output variables. The equations are collectively referred to as a ow, and they are either diierential equations or algebraic deenitions. 1 There is also substantial related activity in Europe under the PROMETHEUS …