Project Overview
The Montana Department of Transportation (MDT), in partnership with Frontier West, Robert Peccia & Associates, and Morrison-Maierle, is preparing to replace fourteen aging timber bridges along U.S. Highway 12 (US 12) west of Forsyth. Two new bridges will be constructed to enhance roadway safety features and route reliability, and twelve reinforced concrete culverts will be installed.
The existing timber bridges are in fair to poor condition, and some currently have weight restrictions. Replacing these structures will remove restrictions and improve traffic flow with updated guardrails and wildlife crossing signs.
MDT is committed to maintaining Montana’s critical infrastructure through cost-effective, long-term solutions. By investing in modern, durable structures, MDT ensures the continued safe operation of the bridges for many years.
Project Map
Why is this project important?
Montana’s timber bridges are reaching the end of their serviceable lives. Many of these structures are in fair to poor condition and have weight restrictions. The MDT Bridge Bureau, responsible for approximately 4,500 bridges statewide, has identified these 14 structures as high priority for replacement.
Replacing these structures will:
- Remove weight restrictions currently in place at multiple locations
- Enhance safety features with updated guardrails and wildlife crossing signs
- Ensure long-term reliability for agricultural, emergency, and daily traffic use
- Maintain year-round access for communities, businesses, and emergency responders
The design-build approach streamlines project delivery, reduces costs, and ensures efficient construction while meeting state and federal safety standards.
What does this mean for the public?
The project will impact local travel on US 12 between Ingomar and Forsyth. MDT will work to minimize disruptions and keep the public informed about construction schedules, detours, and temporary road restrictions.
Construction will include:
- Temporary detours (shoofly routes) will be provided to maintain traffic flow at select locations; these routes will be clearly marked
- Alternating single-lane closures with flaggers or traffic signals
- Short-term width restrictions (16 feet standard; occasional 12-foot restrictions for up to 5 days with advance notice)
- Continued access to emergency vehicles, school buses, and agricultural equipment
MDT recognizes that US 12 is a vital corridor for local events. The project team is committed to coordinating with event organizers and providing timely updates to minimize travel disruptions.
Process and Anticipated Schedule
Phase 1 – Preliminary Design: November 2021 to May 2024
- MDT and TD&H Engineering conducted site evaluations and developed replacement strategies
- MDT and TD&H completed preliminary environmental and traffic impact assessments
- MDT issued design-build requests for proposals in Spring 2024
Phase 2 – Final Design and Construction: Spring 2024 to Fall 2026
- Final construction plans will be developed by Spring 2025
- Construction will begin in April 2025 and, depending on weather conditions and other factors, will continue for approximately 2.5 years.
Bridge List
| Bridge ID | Feature Intersected | Location | Route | Mile Marker | Construction Year |
| 05495 | Middle Fork Froze to Death Creek | 3 Mi W Ingomar | US 12 | 227.310 | 2026 |
| 05496 | Drainage Ditch | Ingomar | US 12 | 229.340 | April 2025 |
| 05497 | Drainage Ditch | 35 Mi NW Forsyth | US 12 | 235.872 | April 2025 |
| 05498 | Drainage Ditch | 32 Mi NW Forsyth | US 12 | 238.172 | 2026 |
| 05499 | Drainage Ditch | 32 Mi NW Forsyth | US 12 | 238.979 | 2026 |
| 05500 | Drainage Ditch | 31 Mi NW Forsyth | US 12 | 239.812 | 2026 |
| 05502 | Drainage Ditch | 25 Mi NW Forsyth | US 12 | 245.311 | 2026 |
| 05504 | Horse Creek | 20 Mi NW Forsyth | US 12 | 250.562 | 2026 |
| 05505 | Anderson Creek | 19 Mi NW Forsyth | US 12 | 252.09 | 2026 |
| 05506 | Drainage Ditch | 18 Mi NW Forsyth | US 12 | 253.022 | July 2025 |
| 05507 | Drainage Ditch | 16 Mi NW Forsyth | US 12 | 254.501 | July 2025 |
| 05508 | Stockpass/Drainage Ditch | 14 Mi NW Forsyth | US 12 | 256.999 | April 2025 |
| 05511 | Big Porcupine Creek Drainage Ditch | 12 Mi NW Forsyth | US 12 | 258.366 | 2026 |
| 05512 | Stockpass | 12 Mi NW Forsyth | US 12 | 258.552 | July 2025 |
| Key: Planned for April 2025 Planned for July 2025 Planned for 2026 | |||||
Engineer to English
Design-Build: This integrated project delivery method allows the design and construction teams to work under a single contract, improving efficiency, reducing costs, and accelerating project completion.
UPN: 9886