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The design of transportation facilities such as roadway intersections is generally influenced by the turning capability of one or more design vehicles and their swept paths.
A review of existing methods and tools for simulating turning vehicle shows that these methods and tools have several disadvantages and are not suitable for use in computer aided design and drafting systems (CADD). CADD systems ideally require an interactive application for simulating turning manoeuvres of design or user-defined vehicles.
This thesis describes the principles of a CADD model and an interactive computer program known as AutoTURN which is based on these principles. AutoTURN is an AutoCAD-based program written in AutoLISP and "C" language. The program which operates within AutoCAD's graphic environment is a user friendly and a highly effective and practical design tool. It allows the user to select a design vehicle including long combination vehicles such as A, B and C trains, define any steering path consisting of circular curves and tangent element and complete tracking or swept path analysis directly within the drawing base utilizing AutoCAD's graphic capability. In this manner, the program enhances the automation process afforded by CADD systems in the design and drafting of transportation facilities. The program has been validated against several methods and found to be an acceptable design program.