Short Cyclic Algorithm for Turbo Block Construction

This paper presents perhaps the shortest possible algorithm for drafting a turbo block in a standard CAD environment. Though not defining the complete turbo roundabout geometry (the legs are defined by their centerlines only), turbo block construction stays at the very core of its geometrical definition. Relevant national policies elaborate turbo block construction at various levels of detail. Some policies skip certain definitions of spirals’ centers and some even allow for slight discontinuities in spiraling lanes’ geometries. But, as our computer program had to be based on precisely defined geometrical features, no question, be it a location of a particular center or relation between the interconnecting arcs, could be left unanswered. Consequently, while explaining the basics on which the program relies, all the elements of the turbo block are discussed. Even the problems not addressed in renowned national policies (such as alternatively matching marking and curb lines) had to be resolved before being incorporated into the program. After resolving and elaborating turbo block roundabout technics in detail, a new cyclic algorithm for turbo block construction is presented. The program is very short and could be easily understood and modified by the average programmer.