Forum and Green Meadows roundabout survey

The City of Columbia Public Works department would like to know what residents think of the roundabout at Forum and Green Meadows compared to the all-way stop that was previously at the intersection.

In the summer of 2019, the roundabout at the intersection of Forum Boulevard and West Green Meadows Road was constructed, replacing an all-way stop. Since Forum Boulevard is a four-lane divided road and West Green Meadows Road is a two-lane road, the all-way stop had made it difficult for drivers to know who had the right-of-way when multiple vehicles stopped at the same time. This confusion caused delays and increased the potential for collisions.

Prior to the roundabout’s construction, City of Columbia Public Works staff received many complaints about the intersection. Drivers would often fail to come to a complete stop, attempting to outpace other vehicles entering the intersection. In addition, the intersection was reported to be difficult and dangerous for pedestrians to cross. During peak traffic hours, the intersection transformed into a bottleneck, with vehicles queuing at stop signs, resulting in stop-and-go situations. Recognizing the need for improvement, most residents agreed that changes were necessary.

Various redesigns were proposed for the intersection, and residents voiced concerns about replacing it with a roundabout. These included that drivers on the southwest leg of Green Meadows would not be able to enter the roundabout, that there were no other double-lane roundabouts in Columbia, that drivers do not know how to navigate roundabouts and that roundabouts are not safe for pedestrians and bicyclists.

The construction of the roundabout was ultimately approved for the following reasons:

• A roundabout changes the geometry of the intersection in a way that forces drivers to slow down and alter their direction. This results in fewer and less severe collisions. At roundabouts, the most severe types of crashes (right-angle, left-turn and head-on impacts) are unlikely to occur because of this geometry.

• A roundabout reduces the number of conflict points. A conflict point is any location within the intersection where vehicles' paths can merge, diverge, or cross and are the most likely locations for collisions to occur. A roundabout eliminates both the left-turn and head-on conflict points when compared to an all-way stop.

• Pedestrians crossing a roundabout only face potential vehicular conflicts from the specific leg they are crossing. In contrast, crossing an all-way stop intersection exposes pedestrians to potential conflicts from all legs simultaneously. Roundabouts also provide median islands where pedestrians can safely wait at each leg of the intersection.

• Vehicular speeds are lower at roundabouts. Crosswalks are also set further back, allowing drivers more time to react to pedestrians and other vehicles.

• Roundabouts reduce congestion, creating a steady flow of traffic from multiple, conflicting traffic streams without stop-and-go conditions. Roundabouts keep traffic flowing during non-peak periods, as vehicles do not need to stop for an all-way stop or signalized intersection when there is little or no traffic from the conflicting direction.

• Roundabouts offer long-term cost savings when compared to the electrical and maintenance requirements of traffic signals. Additionally, roundabouts are blackout-proof, providing uninterrupted service to drivers regardless of electricity.

The feedback period has closed as of July 15. We thank you for your comments.