Mini Roundabout

The illustration above depicts an intersection of two one-way streets, each with two travel lanes. The allocation of space in this intersection is unbalanced as these streets have very low traffic volumes but vehicles have most of the space. Parking is unregulated and vehicles are parked near the intersection corners.

Large corner radii create a dangerous condition due to vehicles turning at high speeds and conflicting with pedestrian movement.

A lack of marking at the intersection creates uncertainty about the space dedicated to each user.

Bandung, Indonesia.

Mini roundabouts are an ideal treatment for unsignalized intersections of small-scale streets. They have been shown to increase  safety at intersections, reducing vehicle speeds and minimizing the points of conflict.

In this type of intersection, motorists must yield to pedestrians and vehicles already in the intersection. Pedestrian crossings should be marked to clarify where pedestrians should cross and that they have priority.

 Install mini roundabouts using simple markings or raised islands. Apply them in conjunction with plantings or small trees, which  enhance the traffic calming effect and beautify the street.

 Provide a clearance of approximately 5 m from the corner to the widest point in the roundabout. A clearance of less than 5 m is  possible by providing mountable curbs on the edge of the roundabout.

When pedestrian volumes are high, consider raised crosswalks to further reduce vehicle speeds.

 Add curb extensions to shorten the crossing distance, protect pedestrians waiting to cross, daylight the intersection, and prevent dangerous illegal parking close to the intersection corners.

 Plant trees, and add bioswales and rain gardens on curb extensions and widened sidewalks.

Austin, USA. A mountable curb in a neighborhood roundabout allows larger vehicles to navigate the intersection when required, while calming everyday traffic.