Take Action: I-229 Exits on Cliff and Minnesota Ave

Take Action: I-229 Exits on Cliff and Minnesota Ave

Take Action: I-229 Exits on Cliff and Minnesota Ave

The comment period for the interchange projects at I-229 and Cliff and I-229 and Minnesota is underway. To see information on the projects click on the links above. 

I encourage you to comment on these projects before December 5. You can comment on one or both projects. Both links take you to a comment section.

Both projects are focused on moving vehicles on, off, and through the I-229 intersection quickly and expeditiously. Both projects also are located where there is great non-vehicular use for Lincoln High, the greenway, and retail at both locations. Given this mix, safety is of an even greater concern than other single point interchanges in Sioux Falls, such as the one on I-29 and Benson Road.  

In your letter do three things. First, identify how you use the project corridor. This can be more than one thing such as drive to work, walk to school, ride your bicycle from north of I-229 to the bike trail, walk with your family through the corridor, etc. 

Next, emphasize that safety is a main concern given this mix of vehicles, pedestrians, and cyclists. The higher the vehicle speed, the greater the danger to pedestrians and cyclists. Measures must be designed into the project to reduce speed of vehicles and ensure separation of vehicles from pedestrians and cyclists for their mutual safety.

Finally, say what you want to see happen. There are many ideas out there. Below are a few. Pick two or three to include in your letter.

  • Have a well-lit tunnel go under one set of the ramps at each project to provide safe movement of pedestrians and cyclists across the I-229 corridor
  • Narrow the lanes of Cliff from 11’ to 10’ or 10.5’. Narrower lanes serve to slow traffic while not affecting travel time
  • Have the ‘free-right’ lanes have a hard right turn onto the ramp. This will serve to slow the movement of the vehicles
  • Have rumble strips in the ‘free-right’ lanes to alert drivers and slow the vehicles
  • Plant as many trees as possible as this not only adds to the attractiveness of the corridor, but also serves to slow speeds
  • Have a 6’ sidewalk on one side and a 10’ side path on the other side at both projects
  • Provide safe east-west pedestrian/cyclist crossing on both Cliff and Minnesota at points close to the interchange
  • Have good lighting at the single point interchange

Thanks for taking the time to make your voice heard. With a wide variety of voices safety in these projects will be included for all.

Greg Boris



When I-229 was constructed over 60 years ago, the stretch from Cliff Ave to the west marked the defacto southern boundary of Sioux Falls. Up until 1955 a portion of that area was a separate city, South Sioux Falls, SD. There were some residences and limited retail and commercial activity. Since then, Sioux Falls has grown significantly increasing its population threefold with a lot of that growth south of I-229. 

In recent years the city, state, and federal government have studied and begun improvements along the I-229 corridor. These improvements include creating and then increasing the capacity of the Louise Avenue interchange, connecting I-229 with I-29 facilitating travel in all directions, providing a single point interchange on 10th St, adding an exit at Benson Road, and now reconstructing the 26th St interchange. In addition a third lane was added in each direction to enable safer movements onto the interstate and into the exit lane.

The interchanges at Cliff and Minnesota are next to be addressed. The process takes a while and has several opportunities for public input. The last of these public meetings was in January, 2019 at Lincoln High. Many people were in attendance, including bicyclists. Following the large group presentation those attending could visit with project staff and have more specific questions answered.

One of the questions that bicyclists asked project staff was where, in all the material, was design work for bicycles and pedestrians. The answer was that such work has not been done yet, but will be done.

Now the project is at its next step with a virtual public meeting. The videos found here for Cliff and here for Minnesota provide more detailed project background and preferred alternatives. To view all of them take about an hour.

The project’s bicycle and pedestrian aspects are quite simple. For Cliff Avenu, put in a 6’ sidewalk on the west side and a  10’ side path on the east side. The end points of these facilities are not described in the presentation, though earlier documents suggest that the area in question is from the Big Sioux Bridge north to 38th St. In addition, there would be a user activated signal to support safe crossing at the four points on each side of Cliff crossing the single point interchange. A similar approach is envisioned for Minnesota Avenue. User activated signals also will be installed to help with safety in north-south travel.


Normally, projects such as those at I-229 and Cliff and I-229 and Minnesota would have a public meeting. With the pandemic and the need to be safe, such public meetings are not being held. Instead two sets of videos, one for each interchange have been developed. 

These videos convey what would have been presented at in-person public meetings. What is not occurring is the interaction between presenters and those in attendance regarding questions that may arise.

Watch these videos. Learn about the project. Then go to the Analysis page and see what this can mean for bicyclists and pedestrians. 

Most important is that you use this information to write comments about the project and send it in. If enough people comment, we will be heard. 


Cliff Avenue and I-229

Minnesota Avenue and I-229

Project Analysis

Several factors come into play when looking at a transportation project as it applies to bicyclists and pedestrians. These are safety, ease of use, and accommodating a wide variety of users. The following chart looks at both projects which call for a 6’ sidewalk on one side and a 10’ side path on the other with user activated signal crossings. The lanes for traffic would be 11’ and the speed would be posted at 30mph except in school zones when students are present. Then it is 15mph zone. Other potential aspects were not discussed in the videos.

Bicycle and pedestrian aspects of the interchange projects

Positives Negatives
Crossing at Single Point Interchange by bicyclists and pedestrians
  • Provides a straight line between two points
  • Provides sufficient width for movement
  • Provides access on both sides of Cliff and Minnesota
  • Provides for user-activated signal to assist with safe north-south crossing
  • Requires that users cross four points where there might be vehicles
  • Not clear if the sidewalk and sidepath are immediately adjacent to the roadway or if there is a buffer. Buffer is preferred for safety
  • Waiting for user-activated signal may have users go before signal engages
  • Not clear if traffic using a ‘free right’ will be required to stop if the user-activated signal is engaged
  • Not clear if there is sufficient lighting for safety under the I-229 bridges by the users of the sidepath and sidewalk
  • Such under-bridge single point interchanges are dark as seen at those along I-29. There is no information about lighting and this is particularly important for pedestrians and bicyclists.
Sidewalk on one side and sidepath on the other side
  • Provides good width for pedestrians and connectivity for bicycle users
  • Provides a sidewalk on the west side of Cliff where there is none now
  • Not clear what is the length of the sidewalks and sidepaths. Where do they start and where do they end? Cliff Avenue should have the bridge as the south end of the sidepath. Cliff Avenue should have the entrance to the park as the south end of the sidewalk. The north end of both should go to the new light.
  • No clear, safe way to get from east to west to convenience store except under bridge on trail or north of interchange at light. Will there be some crossing alternative at the single point interchange?
  • Unclear as to proposed length of Minnesota Avenue sidewalks/sidepaths so comment is tough
  • Requires that users cross four points where there might be vehicles
  • Not clear if the sidewalk and sidepath are immediately adjacent to the roadway or if there is a buffer. Buffer is preferred for safety
  • Waiting for user-activated signal may have users go before signal engages
  • Unclear how many user-activated signals there will be given that there are four points of crossing.
  • Not clear if traffic using a ‘free right’ will be required to stop if the user-activated signal is engaged
  • Not clear if there is sufficient lighting for safety under the I-229 bridges by the users of the sidepath and sidewalk


Tunnel option

There is discussion that tunnels could be constructed underneath the ramps going onto and off of I-229. These tunnels have not been presented in the information material, but city staff is aware of this discussion. 

The tunnels are estimated to cost $1M. It is unclear if this is $1M for each tunnel at Cliff and Minnesota or $1M for both tunnels together. To put this amount into perspective the recent street changes at 41st and Minnesota and 37th and Minnesota cost just above $700K in order to save 11-12 seconds. The city could spend that amount or even more for the safety of pedestrians and bicyclists with tunnels. 

Tunnels would enable pedestrians and bicyclists a safer option than a sidewalk or sidepath. As there are no plans to examine for tunnels, it must be assumed that there would continue to be a sidewalk or sidepath. This would provide options as tunnels can be prone to flooding. 

Tunnels would have to be lit, much as some of the other tunnels are. In addition, this would provide an opportunity for mural. Such public art is public art is found in the I-90 tunnel in Seattle and elsewhere.

Further enhancements to safety for all


Speed of motorized vehicles compromises the safety of all. The higher the speed, the more endangered all are. The hills on south Cliff and south Minnesota find traffic often moving now well above the posted limit. The faster a vehicle moves:

  • The driver’s cone of vision narrows and the ability to react to others in the corridor diminishes markedly
  • The greater the injury to pedestrians, bicyclists, and car occupants in a crash

Posting a speed limit is not enough to lower vehicular speeds. The road must be designed to lower speed. There are design features that can limit speed while not compromising travel time. These include:

  • Narrower lanes. The current plan calls for 11’ lanes. Lanes that are 10-10.5’ wide is sufficient to move anticipated traffic through the project zone. Wider lanes only encourage going faster than is posted
  • Plant trees wherever possible. Trees add character to an area. Trees absorb stormwater. Trees absorb UV and pollutants. Trees reduce urban heat islands. Trees make the areas more inviting.

Free Right Turns

The design calls for and celebrates the smooth, fast movement of cars onto I-229 using free right turns. Using a sidewalk/sidepath approach for pedestrians and bicyclists, conflict exists in free right turns. These turns do not slow the movement of vehicles, making it more dangerous for pedestrians and bicyclists.

The goal of a free right turn is to smoothly transition a motorized vehicle from a city street to an entrance ramp. This need not be done at high speed. In fact, slowing the speed would enhance safety for pedestrians and bicyclists at no noticeable loss of travel time to the vehicle.

From the presentation material it is not clear if vehicles will have to stop when a user-activated signal is engaged. 

There are at least two ways to design slower speeds into free right turns. One or both can be used. They are:

  • Having as close to a 90 degree turn for the free right. This forces a slower speed. Soft curves only serve to encourage faster speeds.
  • Include rumble strips in the free right lane as a reminder to the vehicle that it needs to slow down when taking the turn

Access to the Greenway

Adjacent to the single point interchange is the Sioux River Greenway. This major city attraction draws people from all over, many of whom drive to use it. 

At both Minnesota Avenue and Cliff Avenue are entry points to the Greenway. In addition to the trail, both areas are heavily used by the soccer community. A dog park is near Cliff Avenue as is a playground. There is need for safe vehicular movements both in and out of these two parts of the Greenway. General statements are made in the presentation materials about safe access, but with no specifics. This needs to be more clearly addressed.

Access to retail site in the southwest part of the Cliff Avenue project

The small strip mall at this location has two businesses in it and will be the case for the foreseeable future. There needs to be further examination of vehicular access and exit from this site.

Access to Lincoln High

This school of 2000 students and well over 100 staff finds movement through this corridor 180+ days a year with peak hours at the beginning and end of the school day. In addition, school events draw many people there in the evening. The need for safe movement of vehicles in and out of the parking areas as well as safe movement of people walking or cycling to and from school is important in this very densely used area of Sioux Falls. The plan says little about enhancing safety aside from closing an access point, aligning 41st with the parking lot, and moving the pedestrian signal to the north. 

The project developers are communicating with the Sioux Falls School District about this project. There also needs to be conversations with students and staff to get their thoughts on the project.



1 Comment

  1. Muir, Jim

    Says December 05, 2020 at 10:15 pm

    I think Sioux Falls should add pedestrian / bike at all major intersections.

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