Analysis of Traffic Capacity and Design for the Reconstruction of a Large Roundabout in the City of Zagreb

The paper deals with the issues regarding the need for the reconstruction of a large three-lane roundabout with the reached AADT traffic of over 90, 000 [veh/day] and intense tram traffic at the level below the road surface. Since the existing roundabout dates back to 1985, the design solution with tangential merging of three-lane approaches provides an additional cause and reason for reduced capacity and safety component of the entire intersection. In the new urban, and commercial and spatial surrounding, with the help of radical reconstruction it is necessary to achieve a modern design solution, for which purpose extensive interdisciplinary research was conducted. Common multidisciplinary methods and criteria are presented in six proposed design solutions, with particular focus on the capacitive-safety and design elements and their interrelations.