Rotatória

Rotatória is a type of at-grade circular intersection used to manage traffic where several roads meet. It consists of a circular roadway around a central island, with vehicles entering from approaches and circulating around the island before exiting at another approach. In right-hand traffic systems, traffic typically travels counterclockwise around the island; in left-hand traffic systems, it is clockwise. Vehicles on the roundabout have priority, and entering traffic yields.

Operation and design principles emphasize safety and efficiency. Approaches use signage and often a yield (give way) control to allow circulating traffic to pass before entering. Modern rotatórias can be single-lane or multi-lane, and may include splitter islands to channelize traffic, refuge areas for pedestrians, and crosswalks at each exit. Large or high-volume roundabouts sometimes employ dedicated truck aprons around the central island to accommodate heavy vehicles without encroaching on the circulating lanes.

Variants include mini-roundabouts (small-diameter, low-speed), single or turbo roundabouts (designed to improve capacity and reduce congestion), and signal-controlled roundabouts (which use traffic signals at peak times). Pedestrian and cyclist facilities are commonly integrated, with crosswalks and priority rules informed by local regulations.

Benefits and considerations: rotatórias can reduce injury crashes and improve traffic flow by lowering speeds and eliminating certain conflict points. They require careful design for line markings, sight distance, and appropriate channelization; poor signage or lane ambiguity can lead to confusion and incidents. They are widely used in Portuguese-speaking countries and other regions as a flexible solution for urban and rural intersections.