Challenge

The 36th Street/Hill Road/Catalpa Drive intersection in Boise, Idaho, existed as a skewed, five-leg signalized intersection. Half- to one-mile long lines of cars were not an uncommon occurrence at the intersection, especially during school start and end times at Hillside Junior High School located at the intersection. Safety of school children, as well as of pedestrian and bicyclists, was a major concern amongst those who regularly traveled through the intersection.

Solution

As far back as the 1980s, alternatives to the traffic signal began to be evaluated for the intersection. In 2005, a circular roundabout was chosen as the preferred alternative due to the anticipated safety and operational benefits it would provide. However, in 2008, the dogbone-shaped roundabout emerged as the best alternative, as it would minimize property and existing infrastructure impacts and cut the cost of the project by more than half.

Kittelson worked closely with Ada County Highway District staff to establish and promote the benefits of the dogbone roundabout to local citizens, neighborhoods, and school administration staff. Kittelson developed the preliminary design for the roundabout, along with provisions that would allow the roundabout to be expanded in the future if necessary; and prepared portions of the construction plans package, which included several key pedestrian and bicycle treatments to address the safety concerns.