Abstract
The traffic capacity of a roundabout depends very much on the existing traffic volumes on each approach, each direction of travel having an impact on the other movements in the intersection, especially on those with which it conflicts.
Roundabouts where the turning maneuver has significant values, such as roads / streets where the left turn is allowed at long distances, substantially influence the capacity of the approach with which it intersects. This maneuver includes calculating delays and vehicle queues at all other arms, resulting in a reduction in their capacity and, ultimately, in the entire intersection.
As can be seen from the results of the analyzed roundabout, U-turn (which replaces the left turn movement) produces a significant increase in delays on the rest of the approaches, thus preventing further development of the community.