Structure L49126000+02001 · Sweet Grass County, MT

Susie Creek RD over Boulder River 045

Carries Susie Creek RD over Boulder River 045, 1m S Mcleod.

Overall conditionFair

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

How ratings work
Deck6/9 · Satisfactory
Superstructuresets the rating5/9 · Fair
Substructure6/9 · Satisfactory
Channelnot part of overall7/9 · Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
CAR · 15 FT118 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 6/9Superstructure 5/9 · sets the ratingSubstructure 6/9

118 ft end to end. Lengths and the car 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.

Built1960rebuilt 1997
Length118.1 ft36 m
Daily traffic100counted 2025
Last inspectedAugust 2024every 24 months

Location

StateMontana
CountySweet Grass
Location1m S Mcleod
CarriesSusie Creek RD
CrossesBoulder River 045
Coordinates45.63869, -110.11279

Physical Characteristics

MaterialWood or Timber
DesignStringer/Multi-beam
Total Length118.1 ft (36 m)
Max Span59.1 ft (18 m)
Deck Width16.1 ft (4.9 m)
Deck Area176.4 sq m
Main Spans1
Year Built1960 (reconstructed 1997)

Traffic

Avg Daily Traffic100 (2025)
Truck Traffic3%
Lanes On Bridge1

Inspection & Ownership

Last InspectionAugust 2024
Inspection FrequencyEvery 24 months
OwnerCounty Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour Critical5 — Stable for scour
Structure NumberL49126000+02001

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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