Structure I00094137+04601 · Custer County, MT

I 94 over Tongue River

Carries I 94 over Tongue River, 1m S Miles City.

Overall conditionFair

Set by its lowest-rated component: Deck at 5 of 9.

How ratings work
Decksets the rating5/9 · Fair
Superstructure6/9 · Satisfactory
Substructure6/9 · Satisfactory
Channelnot part of overall7/9 · Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT294 FT OVERALL50 FT0ELEVATION · LENGTHS TO SCALE
Deck 5/9 · sets the ratingSuperstructure 6/9Substructure 6/9

294 ft end to end, longest span 112 ft: about 4 semi-trucks nose to tail. Lengths and the semi-truck on the deck are drawn to the same scale. Each part is colored by its latest inspection rating. The inventory records lengths but not heights or the layout of the shorter spans, so those are drawn as typical for a multi-beam bridge.

Built196165 years old
Length294.0 ft89.6 m
Daily traffic4,707counted 2023
Last inspectedJune 2023every 24 months

Location

StateMontana
CountyCuster
Location1m S Miles City
CarriesI 94
CrossesTongue River
Coordinates46.38472, -105.84546

Physical Characteristics

MaterialSteel Continuous
DesignStringer/Multi-beam
Total Length294.0 ft (89.6 m)
Max Span111.9 ft (34.1 m)
Deck Width31.8 ft (9.7 m)
Deck Area869.1 sq m
Main Spans3
Year Built1961

Traffic

Avg Daily Traffic4,707 (2023)
Truck Traffic23%
Lanes On Bridge2

Inspection & Ownership

Last InspectionJune 2023
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour Critical7 — Countermeasures installed
Structure NumberI00094137+04601

How Bridge Ratings Work

Inspectors rate each major part of a bridge (the deck you drive on, the superstructure of beams that holds it up, and the substructure of piers and abutments beneath) on a 0–9 scale. A bridge's overall condition is its lowest of those ratings, so one deteriorated component makes the whole bridge "poor."

0Failed
1Imminent failure
2Critical
3Serious
4Poor
5Fair
6Satisfactory
7Good
8Very good
9Excellent
Good · lowest component 7–9
Fair · lowest component 5–6
Poor · lowest component 0–4

A poor rating is not a closure. It means the bridge is flagged for priority repair or replacement; bridges judged unsafe are closed or posted with weight limits. The waterway (channel) rating is reported, but it does not count toward the overall classification.

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