Structure C507 · Blaine County, MT

IRR BIA RTE 8 over Peoples Creek

Carries IRR BIA RTE 8 over Peoples Creek, 22.5 Km SW Of Dodson.

Overall conditionFair

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

How ratings work
Decksets the rating6/9 · Satisfactory
Superstructure7/9 · Good
Substructuresets the rating6/9 · Satisfactory
Channelnot part of overall5/9 · Fair
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
SEMI-TRUCK · 72 FT147 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 6/9 · sets the ratingSuperstructure 7/9Substructure 6/9 · sets the rating

147 ft end to end, longest span 62 ft: about 2 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.

Built197650 years old
Length147.0 ft44.8 m
Daily traffic200counted 2024
Last inspectedOctober 2024every 24 months

Location

StateMontana
CountyBlaine
Location22.5 Km SW Of Dodson
CarriesIRR BIA RTE 8
CrossesPeoples Creek
Coordinates48.28097, -108.44569

Physical Characteristics

MaterialPrestressed Concrete
DesignStringer/Multi-beam
Total Length147.0 ft (44.8 m)
Max Span62.0 ft (18.9 m)
Deck Width34.1 ft (10.4 m)
Deck Area465.9 sq m
Main Spans3
Year Built1976

Traffic

Avg Daily Traffic200 (2024)
Truck Traffic10%
Lanes On Bridge2

Inspection & Ownership

Last InspectionOctober 2024
Inspection FrequencyEvery 24 months
OwnerBureau of Indian Affairs
Historical SignificanceBridge is not eligible for the National Register
Scour Critical8 — Stable, low risk
Structure Number00000000000C507

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.