Structure L24630000+06001 · Lake County, MT

S Ferndale DR over Swan River 102

Carries S Ferndale DR over Swan River 102, 2m SE Ferndale.

Overall conditionFair

Set by its lowest-rated component: Deck at 6 of 9.

How ratings work
Decksets the rating6/9 · Satisfactory
Superstructure7/9 · Good
Substructure7/9 · Good
Channelnot part of overall8/9 · Very Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT308 FT OVERALL50 FT0ELEVATION · LENGTHS TO SCALE
Deck 6/9 · sets the ratingSuperstructure 7/9Substructure 7/9

308 ft end to end, longest span 77 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.

Built200719 years old
Length308.1 ft93.9 m
Daily traffic100counted 2025
Last inspectedNovember 2023every 24 months

Location

StateMontana
CountyLake
Location2m SE Ferndale
CarriesS Ferndale DR
CrossesSwan River 102
Coordinates48.03332, -113.97594

Physical Characteristics

MaterialPrestressed Concrete
DesignStringer/Multi-beam
Total Length308.1 ft (93.9 m)
Max Span77.4 ft (23.6 m)
Deck Width32.5 ft (9.9 m)
Deck Area929.6 sq m
Main Spans4
Year Built2007

Traffic

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

Inspection & Ownership

Last InspectionNovember 2023
Inspection FrequencyEvery 24 months
OwnerCounty Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour Critical8 — Stable, low risk
Structure NumberL24630000+06001

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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