Development Type: Potential Roadway Cul-de-Sac
Services Provided: Traffic Impact Study
Client: City of Elk River
A roadway corridor in the City of Elk River is being utilized as a primary route between two key intersections. This route is shorter than the agency-desired route, which is part of the reason drivers take it. The other reason is that it avoids the potential delay from having to stop at one traffic signalized intersection. While attractive for drivers, it has raised concerns. The City contracted with Spack Consulting to explore the traffic impacts of a proposed cul-de-sac on this roadway corridor in comparison to the existing conditions.
This project involved several types of data collection (counts, time travel runs, etc.) to fully explore the existing conditions as well as forecasting for three alternative roadway conditions (i.e. locating the cul-de-sac in one of three potential spots). The analyses covered intersection operations, changes to travel times for commuters (essentially using the road as ‘cut-thru’ route) as well as for residents and businesses along the route, and potential geometric or traffic control changes to better accommodate traffic for any scenario.
Our report made a recommendation to keep the corridor ‘as is’ without a cul-de-sac, primarily as the existing operations were not as dire as the perception of operations. The City Engineer presented the study findings to his Council and was immediately greeted with questions that stretched his ability to fully answer. As originators of the work, we were then asked to attend a Council Workshop to allow for a deeper discussion of the study and ultimate recommendations.
To prepare for the workshop, our prep work included the following:
Through this process, we determined there was a key misunderstanding of our process and traffic impact studies in general. Another key point was the difference between acceptable operations by our standard measures versus the perception.
This preparation paid off in a great Council Workshop. We discussed the overall process, answering additional questions about standards, like how much existing data is appropriate to analyze operations (we collect two days of turning movement counts for our studies) and how we choose the study intersections. Discussing Level of Service and overall intersection delays lead us to point out that while individually each intersection was acceptable, driver frustration builds if the intersections are viewed in combination (like how drivers see them). So waiting 30 seconds at one intersection may not be an issue, but waiting 30 seconds at multiple intersections in a row is what can build driver frustration. A final point we made was that this study accounted for traffic impacts only. The Council obviously needed to considered other factors before it decided to accept our recommendation or go a different route.
Ultimately, the Council decided against our recommendations, authorizing the City Engineer to move forward with plans for a cul-de-sac in a specific location. However, the discussion with the Council and the traffic information in our report was still a valuable component that provided the path toward a sensible conclusion. It may not have been our original recommendation, but we were still happy with how this project turned out.