OPTIMIZATION OF ROUNDABOUT DESIGN ELEMENTS

Preliminary notes Analysis of roundabouts constructed in several Croatian cities has shown that the developed intersection areas, when reconstructing the classical intersections into roundabouts, have limited the outer radius of the intersection as a rule. Croatian guidelines for roundabout design and equipment, for capacity calculation of small and medium roundabouts suggest application of the Austrian method which takes into consideration the design conditions at intersections, which is why it has been applied in this paper for analyzing the correlation between the intersection design and capacity. Since urban locations do not always allow application of the optimal radius, this paper analyses the way of optimizing the radius and other elements of the intersection in relation to capacity. The results have shown that the roundabout entrance and exit parameters as well as the achieved distance between the conflict points have an impact on roundabout capacity and the optimization of its size as a function of the capacity can rationalize the area needed for the intersection