Kiertoliittymistä

Kiertoliittymistä, commonly known as roundabouts or traffic circles, are a type of circular intersection designed to improve traffic flow and safety. They replace traditional signalized intersections or stop signs at junctions where multiple roads meet. In a roundabout, traffic flows in a counter-clockwise direction around a central island. Vehicles entering the roundabout must yield to traffic already circulating within it. This continuous flow of traffic, managed by yielding rather than stopping, can reduce vehicle delays and queues.

The design of kiertoliittymistä typically includes approach lanes that curve into the circular roadway, a central island that may be landscaped or marked, and exit lanes. Pedestrian crossings are usually located on the approaches to the roundabout, set back from the circulatory roadway to provide a safer crossing point. Bicycle facilities can be integrated in various ways, either by providing separate paths or by allowing cyclists to use the roadway with motor vehicles, depending on the design and local regulations.

Studies have shown that kiertoliittymistä can significantly reduce the severity of crashes compared to traditional intersections. This is due to lower speeds within the roundabout and the elimination of high-risk conflict points, such as head-on or right-angle collisions. While they can be effective in managing traffic, their introduction requires careful consideration of traffic volumes, speeds, and the needs of all road users, including pedestrians and cyclists. Effective signage and driver education are crucial for their safe operation.