SAFETY AND CAPACITY ASSESSMENT OF NON-STANDARD ROUNDABOUTS.

Traffic volumes in road traffic show growth, especially in developed countries. Where necessary and depending on space, financial possibilities and other aspects, increasingly more capacity roads (multi-lane highways, complex grade-separated interchange, etc.) are being built. The places, where the roads meet (i.e. at the intersections), are the most problematic (traffic accidents, capacity problems, etc.). Standard intersections (i.e. level intersections, roundabouts, intersections with traffic lights or grade-separated interchanges) do not fulfill their task. Traffic designers, in collaboration with traffic engineers, therefore design non-standard types of intersections, which are basically combinations of standard ones. For example, turbo-roundabouts, roundabouts with traffic lights, double roundabouts, and multiple roundabouts, are created. The paper deals with the roundabouts with traffic lights. This type is not common intersection type in the Czech Republic. On the other hand, for example in Holland, it is quite common to meet a turbo roundabout with traffic lights. Some of them are very complicated - for example, with seven traffic lanes on one entrance to the intersection. However, despite their complexity, the traffic on them is smooth. The paper describes the roundabouts with traffic lights from a safety point of view (analysis of conflict situations) and from a capacity point of view. [ABSTRACT FROM AUTHOR]