Staff recommends that the Planning Board listen to the presentation on the 21st St. Underpass Study, hold a public hearing, and receive public comments. Following the public hearing, staff recommends that the Planning Board forward a recommendation for adoption of the 21st Street Underpass Study to the Policy Coordinating Committee.

The 21st St. Underpass is one of two grade-separated railroad crossings that link downtown Billings to the industrial and residential area south of the railroad. The 21st Street crossing is unique because it is the only grade-separated crossing that serves the central downtown area, making it one of the critical railroad crossings in Billings. However, there are significant limitations to the current use of the 21st Street underpass, including:

• Lack of vertical clearance for large vehicles (current clearance is 8 ft).
• Narrow lanes without shoulders.
• Lack of bicycle lanes or other options for bicycles.
• Narrow, dark, debris-prone sidewalks for pedestrians.
• Periodic roadway drainage problems.
• Steep roadway grades on both approaches to the underpass.

After the Montana Department of Transportation (MDT) concluded that it would not construct a grade-separated crossing at the 27th St. railroad crossing due to community preference, the City considered improving the 21st St. underpass to allow additional types of vehicles to utilize the underpass. The City placed a project to improve the 21st St. underpass in its Capital Improvement Plan (CIP). As a result, the Billings Metropolitan Planning Organization (MPO) offered to assist in the process with a planning-level study of the underpass to provide options for improvements. The City has since identified the 21st Street underpass as part of its long-range CIP projects list.

Through the Request for Proposals (RFP) process, Kittelson & Associates, Inc. was selected as the consultant for the project with HDR as their sub-consultant. The two firms worked together to conduct an existing conditions analysis and two rounds of public outreach. They also communicated with BNSF Railway, which owns the structure. Based on the planning-level technical analysis completed by experts in traffic and structural engineering, and with input from the public and the project advisory committee, the consultants developed six alternatives for the underpass, which were reduced to four alternatives in consultation with the project advisory committee. The purpose of this study was to provide options to the City of Billings for potential improvements, not to select a particular alternative.

The four alternatives include:

1. Alternative 1: No Build
   1. Alternative 1 maintains the infrastructure currently in place. This alternative means no actions are taken and no additional cost is incurred. This also means that heavy vehicles, including fire and emergency medical service (EMS) vehicles would still not be able to use the underpass. Additionally, bridge involved crashes may still occur due to limited vertical clearance, drainage issues will persist without an upgraded stormwater system, and sidewalks would continue to experience debris accumulation due to unstable slopes.
   2. Cost Estimate: $0
2. Alternative 2: Minor Improvements with Overheight Vehicle Warning System
   1. Alternative 2 adds low-cost improvements with the goals of reducing the overheight vehicle crashes into the overpass bridge and improving the pedestrian environment under the bridge. The alternative includes installing an overheight vehicle warning system, modifying the 21st Street underpass to improve the existing drainage system, and stabilizing the bridge abutment embankment slopes to reduce debris on the sidewalks.
   2. Cost Estimate: $600,000-$800,000
3. Alternative 3: Increase Clearance to 11.5 Feet with Minor Pedestrian Improvements
   1. Alternative 3 includes moderate modifications of the bridge structure to increase the vertical clearance by approximately 3.5 feet to achieve a vertical clearance of approximately 11.5 feet (11’-6”), as well as adding pedestrian improvements and an overheight warning system like Alternative 2. This alternative would accommodate ambulances but continue to not accommodate fire apparatus, large EMS vehicles, and most commercial trucks.
   2. Cost Estimate: $8-10 Million
4. Alternative 4: Increase Clearance to 13.5 Feet with Bridge Replacement
   1. Alternative 4 increases the vertical clearance of the underpass to 13.5 feet. This alternative would allow heavy vehicles, including fire and emergency medical services (EMS), to utilize the underpass. In this alternative, achieving the increase in vertical clearance would require replacing the bridge structure, as the increase in roadway depth would expose existing bridge piles to a depth not meeting structural standards.
   2. Cost Estimate: $26-30 Million

More than 400 people responded to the second survey, which presented the four alternatives. From highest to lowest, the public preferred:

1. Alternative 2 (Minor Improvements with Overheight Vehicle Warning System) 
2. Alternative 3 (Increase Clearance to 11.5 Feet with Minor Pedestrian Improvements)
3. Alternative 1 (No Build)
4. Alternative 4 (Increase Clearance to 13.5 Feet with Bridge Replacement)

BNSF indicated that it would prefer an option that does not impact railroad operations. Of the two construction options, BNSF would prefer Alternative 3.

Another item that must be considered is the underpass's proximity to the Billings PCE federal Superfund site. Construction would likely require mitigation measures to be taken.

21st Street is not currently designated as an urban route within the Billings MPO and, therefore, is not eligible for federal funding through the MPO. To become eligible for federal funding, a request would need to be submitted to MDT to add the roadway to the urban system.

This study is now going through the MPO's review process, in which the governing bodies forward a recommendation of adoption or denial to the Policy Coordinating Committee (PCC), which makes the final decision on the study for the MPO. The expected review schedule is:

• Technical Advisory Committee - May 28, 2026
• Planning Board - June 9, 2026. This meeting includes a public hearing. 
• Board of County Commissioners Discussion - June 11, 2026
• Board of County Commissioners Regular - June 23, 2026
• City Council Work Session - June 15, 2026
• City Council Regular - June 22, 2026
• Policy Coordinating Committee - July 21, 2026

Stakeholders were engaged throughout the process. The project advisory committee included representatives from the Billings City Council, the City and County Public Works Departments, MET Transit, local Tax Increment Financing (TIF) districts, the Montana Department of Transportation, Phillips 66, and more. Councilmember Roy Neese provided valuable insight and suggestions to the study. Consultants met with additional stakeholders, including the City of Billings Fire and Police Departments, and an EMS provider. More than 400 members of the public responded to each round of surveys, which resulted in almost 900 survey responses.

This meeting includes a public hearing where residents can share public comment. 

The consultants also engaged with BNSF to get their feedback on the four alternatives.

The Planning Board may:

• Forward a recommendation of study adoption to the Policy Coordinating Committee.
• Forward a recommendation of study denial to the Policy Coordinating Committee.

A recommendation of study adoption does not commit the City of Billings or any other entities to action. The plan provides options for possible improvements to the 21st St. underpass. Adopting the plan provides the City with the opportunity to pursue grants and other funding sources in the future if they become available. Not adopting the plan would remove these funding opportunities.

There are no fiscal effects to adopting the study, as this is a study only.

If the City of Billings decides to make changes to the 21st St. underpass in the future, there would be a cost to do so, ranging from approximately $600,000 - $30 million. This funding would have to be approved at another time by the Billings City Council and be updated within the CIP. Federal grants and other funding sources outside the City would certainly be considerations in developing this project to move it forward. 21st Street is not currently designated as an urban route within the Billings MPO and, therefore, is not eligible for federal funding through the MPO. To become eligible for federal funding, a request would need to be submitted to MDT to add the roadway to the urban system.