Trunk Highway 23 Restricted Crossing U-Turns (RCUTs), Marshall, Minnesota
Reduced Conflict Intersection
Minnesota Department of Transportation (MnDOT) District 8
A Reduced Conflict Intersection (RCI) is an intersection specifically designed to decrease fatalities and injuries caused by broadside crashes on four-lane divided highways. RCIs are sometimes referred to as J-turns or J-turn intersections, Restricted Crossing U-Turns (RCUTs), or superstreet intersections. In Minnesota, these types of intersections are most commonly referred to as RCUTs.
An RCUT intersection is characterized by the prohibition of left-turn and through movements from side street approaches which are normally permitted in conventional intersection designs. The RCUT accommodates these movements by requiring drivers to turn right onto the main road and then make a U-turn maneuver at a one-way median opening 400 to 1,000 feet after the intersection.
According to the MnDOT website, there are currently thirteen RCUTS in Minnesota with MnDOT currently planning and studying locations for additional RCUTS across the state http://www.dot.state.mn.us/roadwork/rci/.
The following images more clearly show the operation of an RCUT (image taken from the previously noted MNDOT website):
SO, WHY BUILD RCUTs?
According to MnDOT, the benefits of RCUTs include improved safety (studies show a 70 percent reduction in fatalities and a 42 percent reduction in injury crashes where RCUTs are used) and faster to build (RCUTs can be designed and built in approximately one year whereas interchanges typically take 3-5 years). There is also a lower cost associated with constructing an RCUT as opposed to constructing an intersection with a stop light or an interchange.
A United States Department of Transportation Federal Highway RCUT Project Case Study can be found here: https://safety.fhwa.dot.gov/intersection/innovative/uturn/case_studies/mn/mn_rcut.pdf
PROJECT: TRUNK HIGHWAY 23 & LYON STREET PROJECT, MARSHALL, MINNESOTA
Originally, this Trunk Highway (TH) 23 project included the construction of RCUT intersections at two locations in Marshall, Minnesota: TH 23 at Lyon Street and TH 23 at County State Aid Highway (CSAH) 7. However, after design began, this project was split in two by intersection to accommodate a bypass lane design scope change at the intersection of CSAH 7. The design of the TH 23 / Lyon Street RCUT intersection was completed by Isthmus Engineering in the spring of 2018 and built in the summer of 2018. Isthmus has since completed the RCUT design for the intersection of TH 23 and CSAH 7 which is slated for construction this summer.
SOME PROJECT TAKEAWAYS
The design of these intersections were noteworthy projects for Isthmus as they were the first RCUT design lead projects in our office giving us the opportunity to solidify our knowledge in RCUT intersection design. Our previous experience in RCUT design was in the role of sub-consultant.
As the project design lead, Isthmus:
developed and implemented a customized, streamlined comment review process resulting in more efficient review turnarounds
created Machine Control models using advanced corridor modelling
incorporated in the plans the ability to add future snow fence within the project area
We are thankful to the TH 23 & Lyon Street RCUT Isthmus Project Design Team which included Kevin Krech (Design Manager), Amy DeBruin (Quality Manager), Sam Thiele (Roadway Designer), Mike Zmuda (Business Development and Utility Coordination), Amber Nord and Elizabeth Lewen (Signing & Striping), and Avo Toghramadjian (Project Manager). We are also thankful for the MnDOT District 8 Project Team that helped this project flow so smoothly and our sub-consultant SRF Consulting.