Performance Indices for the Characterization of the Safety Level for the Roundabouts.

Rural roundabouts present an important quality: the improvement of the safety characteristics with respect to other intersection typologies of intersection at grade. With the present paper, we want to propose a general methodology which, basing on a series of inputs (geometry, vehicular flows, operative speeds), allows to characterize the performances, in terms of safety, of the roundabouts. The final objective is to determine the performance indices necessary to define the dangerousness level of the roundabouts of great diameter, typical of the rural contexts. These indices will come up to the traditional parameters (level of service, capacity), that defines the roundabout performances only in the terms of the transport service quality. For the covering abstract see ITRD E135448.