The intersection of North Grandview Avenue, Grace Street and Delhi Street in Dubuque, Iowa, had a long history of vehicle crashes and unsafe operations that needed to be resolved. This five-way junction was stop-controlled, yet its geometry was unique enough to continue to be a source of concern. In addition, recent changes to surrounding properties caused more congestion at the intersection, with traffic needing frequent access to the adjacent hospital, local bank, neighboring churches and nearby University of Dubuque.
Five-legged roundabout solution
MSA staff, comprised of team members from the recent acquisition of Ourston Roundabout Engineering, conducted a traffic study to evaluate what improvement would best serve this intersection. It was determined that traffic engineering via a five-legged roundabout would improve efficiency, reduce crash numbers and restore the overall safety of this busy central intersection. A conceptual roundabout layout was created for City officials in order to first apply for a Traffic Safety Improvement Program (TSIP) grant before fully designing the roundabout for construction purposes. The design had minimal right of way impacts and took into consideration the frequent movement of trucks and large vehicles through the area.
As this would be the first roundabout within the City of Dubuque, it was imperative to engage residents, business owners and stakeholders early in order to win support and have the most successful level of project implementation. The MSA team met with local officials and landowners first, then conducted an extensive public involvement campaign to educate the entire community.
Throughout construction, our team continued to provide extensive on-site construction observation and contractor coordination, with frequent and purposeful weekly project updates provided to City staff, impacted residents and business owners along the way. The project was constructed in 2016, with a ribbon-cutting ceremony held on August 22, celebrating “Dubuque’s First Modern Roundabout.”
The Iowa Chapter of the American Public Works Association (APWA) named the North Grandview Avenue/ Delhi Street/Grace Street Roundabout the winner of the Project of the Year Award in 2017.
Twice as nice
After the successful completion and integration of the first roundabout within the City, businesses and residents began to see the true effects of the change. A second troublesome intersection, also located along North Grandview Avenue but this time crossing University Avenue, was slotted to receive a simple traffic light upgrade. After City officials and citizens saw the positive changes happening with the first roundabout, however, they moved to install another at this second location.
The Grandview-University intersection was also a busy one, connecting commuters to the university itself and Dubuque Fire Station No. 4 situated on the corner. The MSA team once again studied the junction and completed a microsimulation model to show how traffic moving through an additional roundabout would interact with the first. That model helped to convince the local residents that a roundabout was the correct solution. The North Grandview Avenue and University Avenue roundabout was constructed in the summer of 2018, with the City receiving full funding for the project from the Iowa DOT.