Montana Truck Bans & Hazmat Routes

Where Montana keeps trucks out

Montana runs no cars-only parkways and no hazmat tunnel ban. On interstates the state posts a clearance sign only when a structure sits under 16 ft, so low overpasses get flagged and tall ones do not. Watch the spring-thaw load limits MDT posts by road and the city truck routes in Billings, Great Falls and Missoula. Placarded and radioactive loads follow 49 CFR 397 and the FMCSA registry. Know your loaded height before you roll.

Key restrictions

• No parkway or hazmat tunnel bans
• On interstates Montana posts a clearance sign only when a structure sits under 16 ft, so low overpasses get flagged and tall ones do not
• Watch MDT spring-thaw load limits posted by road and the city truck routes in Billings, Great Falls and Missoula
• Placarded and radioactive loads follow 49 CFR 397 and the FMCSA registry

• Parkway / road ban: No parkway or commercial-vehicle bans. Restrictions are posted city truck routes, low-clearance structures, and seasonal spring-thaw load limits.
• Hazmat: No metro tunnel or bridge hazmat ban. Placarded and radioactive loads default to the Interstates and any Montana-designated routes in the FMCSA registry (49 CFR 397). Hazmat registration is required for certain types and quantities.
• Through-truck routes: Local jurisdictions post truck routes and weight-limited streets; Billings, Great Falls and Missoula carry route signage. No parkway-style network. Through trucks stay on posted routes; local deliveries take the most direct path to the stop under federal reasonable-access rules.
• Fine: Route, clearance and seasonal-load violations are commercial/traffic offenses with penalties that vary by court and by county; overweight and oversize carry separate schedules. Hazmat routing follows state and federal penalties. Confirm current amounts with MDT.

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