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I 90 over Drainage

Mineral County, Montana · rated Good in the 2025 National Bridge Inventory

United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled August 20, 2026

I 90 over Drainage in Mineral County, Montana, is rated in good condition in the 2025 National Bridge Inventory (as of August 20, 2026).
Its lowest-rated component is the culvert, rated 7 (good condition) on the 0-9 scale.
It was built in 1986, making it 39 years old at the 2025 inventory.
It carries about 8,111 vehicles a day (traffic count year 2023).
Its listed owner is the state highway agency.
It is one of 37 of the 153 inventoried bridges in Mineral County rated good (24.2%); 17 (11.1%) are rated poor.
Its traffic status in the 2025 inventory is open, no restriction (NBI item 41).
Its condition class and component ratings are unchanged from the 2024 inventory.
Its most recent inspection on record is dated August 2024, on a 24-month routine inspection cycle.
A good rating means every major component - deck, superstructure, substructure, or culvert - is rated 7 or higher on FHWA's 0-9 scale: no more than minor problems.

Component ratings

Component	Rating (2024)	Rating (2025)	FHWA scale meaning
Culvert	7	7	Good condition


Structure	Steel culvert
Length	about 21 ft
Location	St. Regis
NBI structure number	I00090033+01001
Condition class	Good
Traffic status (item 41)	Open, no restriction
Last inspection (item 90)	August 2024
Inspection interval (item 91)	24 months
Scour (item 113)	8: foundations stable, scour above the top of the footing

Source: FHWA National Bridge Inventory, 2025 data as reported by the Montana department of transportation.

Bridge	Built	Vehicles/day	Condition
I 90 over Sep Local Road	1973	7,824	Fair
I 90 over Sep Local Road	1973	7,824	Fair
I 90 over Int Taft	1973	7,824	Fair
I 90 over Sep Randolph Creek Road	1973	7,824	Fair
I 90 over St. Regis River	1973	7,824	Fair
I 90 over Int Lozeau County Road	1967	7,649	Good