MDT outlines Silo South widening with shoulders and turn lanes, targets 2030 construction
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Summary
MDT described a pre-30% design for the Silo South project (MP 70.2–75.5) that would widen the corridor to a five-lane cross section with 8-foot shoulders, two-way left-turn lane and passing lanes; MDT said construction is anticipated in 2030 and that wildlife impacts are being coordinated with Fish, Wildlife & Parks.
The Montana Department of Transportation on Jan. 16 told Broadwater County residents it is developing the Silo South project on US 12/US 287 between mileposts 70.2 and 75.5 to address safety and operations. Rebecca Barbula, MDT design project manager, said the project is in early design (under 30% complete) and would include eight-foot shoulders, passing lanes in both directions and a continuous two-way left-turn lane through much of the corridor. Barbula said right-of-way impacts are being minimized and only minor acquisition is currently anticipated.
MDT said the design work is intended to relieve congestion, improve operations and provide safety improvements such as better approach alignment and pullouts. The agency is coordinating with Fish, Wildlife & Parks on wildlife-friendly measures near the wildlife management area; Barbula said MDT is considering modified farm-style fencing and small culverts to support animal movement but that full overpasses or underpasses are likely outside the scope of this project.
MDT staff said the project is working toward a 30% design milestone in 2026 and that construction timing is dependent on final design and funding, with an anticipated construction window around 2030. Agency staff reiterated that the recent state change to allow 75 mph on continuous 4-lane segments (referenced as House Bill 312) does not apply to Silo South because project-plus-existing 4-lane sections do not meet the 10-mile continuous threshold.
Residents at the meeting asked about interim measures — such as signage, no-passing zones and deceleration lanes — and MdT representatives said those are evaluated through traffic and safety reviews; striping and signs can be implemented relatively quickly if data and warrants support them. MDT also noted that safety analyses use up to 10 years of crash data for network-wide reviews but individual project summaries often use shorter windows (three to five years) when developing targeted improvements.
MDT encouraged public comments through its interactive project map and an online comment form and said additional public involvement will be held as design advances. The agency also said project-specific reports will include summaries for public review when they are tied to a project in the planning process.
