I-694/Rice Street Interchange

Challenge

For years, Ramsey County has identified the interchange at Rice Street (CSAH 49) and Interstate 694 (I-694) as a top-priority interchange for reconstruction. Not only is I-694 an important regional trucking route, but Rice Street is one of few north-south arterial corridors in the County. Rice Street crosses I-694 in the stretch with only two lanes in each direction, a bottle neck congested for an average of seven hours per day. With the Minnesota Department of Transportation’s (MnDOT) construction of a third general-purpose lane in each direction in 2017, the County, with support from the cities of Shoreview, Little Canada and Vadnais Heights, planned to reconstruct the Rice Street/I-694 interchange. Construction began in 2020.

The purpose of this project is to address the operational issues at the I-694/Rice Street interchange. Studies show that, by 2040, traffic operations within the existing interchange will fail. Addressing the issues of the interchange will also provide the opportunity to improve transportation efficiency and safety for multimodal and vulnerable users who navigate through the interchange along Rice Street. In addition, a well-functioning interchange will increase the economic development potential of currently underutilized property located within the interchange – particularly the former Ramsey County Public Works site located in the southwest quadrant of the interchange.

Solution

The project team selected a recommended alternative in May 2017 after considering input from community stakeholders and directly impacted property owners along the corridor.

A primary advantage of the selected alternative, an offset single point interchange, is that it replaces the four closely spaced signalized intersections with three roundabouts. This alternative solves the traffic operation problems now and in the future as traffic volumes increase. In addition, this alternative was the lowest overall cost of the various designs that were considered.

Why roundabouts?
The preferred alternative includes roundabouts since this is the most safe, efficient and cost-effective way to address the growing volume of traffic in the area while minimizing the impact to adjacent properties. Roundabouts are a means of intersection control that have gained in popularity and acceptance in recent years. When deciding how to design an intersection, roundabouts are evaluated and compared to other means of intersection control, such as a traffic signal. What roundabouts do provide over other means of control includes the following:

Increased safety
When replacing stop signs or traffic signals, roundabouts have shown an 89% decrease in fatal crashes, a 74% decrease in life-altering injury crashes and a 39% decrease in all crashes. While roundabouts will have vehicle crashes, they are generally less severe than at other intersections due to lower vehicle speeds and one-way traffic flow. Roundabouts have shown a 30-40% decrease in pedestrian crashes and a 10% reduction in bicycle crashes. Navigating a roundabout is easier for pedestrians and bicyclists, as oncoming traffic is only from one direction, and there are multiple refuge points on the medians of the roundabout.

Improved traffic flow experience
Roundabouts have shown that more traffic can be accommodated and feature less delay than at other intersection designs. Studies have shown that vehicle delays are reduced by 20 to 30%. Roundabouts can also function in close proximity to one another without creating traffic backups experienced by other intersections.

Improved access roundabouts
Improved access roundabout allow for additional access to the intersection, which may not be feasible with other intersection types. Roundabouts are designed to accommodate all vehicle types traveling through the intersection, including large semi-trucks.

All alternatives being considered propose to close a number of existing accesses on Rice Street in accordance with the County’s Access Management policy. The intersections on this part of Rice Street are very close together, and there are many accesses in between which impedes traffic flow and is unsafe.

Awards

• 2020 Project of the Year Award | Minnesota County Engineers Association (MCEA)