The TH 33 and I-35 interchange ramp intersection has a history of severe crashes and continues to be a major safety concern for the community, Minnesota State Patrol and MnDOT – it exceeds the critical crash rate for similar-type interchanges and is the fifth highest in Fatal and Serious Injury Crash Rate (FAR) statewide (MnDOT’s 2013 Tool Kit). To address this issue, MnDOT initially led an alternatives analysis effort that identified closing the west leg and extending a new frontage road north along the west side of TH 33, which the community supported. Due to environmental constraints, additional alternatives were evaluated. This effort identified that a roundabout would satisfy traffic needs as well as safety and environmental concerns.
The project site was nearly surrounded by wetland features, which made fitting the roundabout without creating significant impacts a challenge. In addition, the intersection is also frequently used by a significant number of oversize-overweight (OSOW) vehicles, averaging nearly three vehicles per day. The south approach to the roundabout also has high-speed traffic entering from I-35.
The SRF team completed the roundabout design from conceptual level to final construction documents in less than five months. The project required substantial coordination with both MnDOT staff (information was being provided by both District and Central Office staff for design elements) as well as our subconsultants that provided roundabout peer review services and wetland delineation and permitting.
Project deliverables included:
This project was recognized at Bentley’s Year in Infrastructure 2018 Conference – a global gathering of leading executives in the world of infrastructure design, construction, and operations. The annual awards program honors the extraordinary work of Bentley users advancing infrastructure design, construction, and operations throughout the world. Twelve independent jury panels of distinguished industry experts selected the projects from 420 nominations submitted by more than 340 user organizations around the world.