Structure I00094027+03211 · Yellowstone County, MT

I 94 over S 39th RD

Carries I 94 over S 39th RD, 4.3m E Pompeys Pillar.

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
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
CAR · 15 FT71 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 6/9 · sets the ratingSuperstructure 7/9Substructure 7/9

71 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.

Built197650 years old
Length70.9 ft21.6 m
Daily traffic2,255counted 2023
Last inspectedJanuary 2025every 24 months

Location

StateMontana
CountyYellowstone
Location4.3m E Pompeys Pillar
CarriesI 94
CrossesS 39th RD
Coordinates46.00259, -107.91050

Physical Characteristics

MaterialPrestressed Concrete
DesignStringer/Multi-beam
Total Length70.9 ft (21.6 m)
Max Span69.9 ft (21.3 m)
Deck Width44.3 ft (13.5 m)
Deck Area291.6 sq m
Main Spans1
Year Built1976

Traffic

Avg Daily Traffic2,255 (2023)
Truck Traffic30%
Lanes On Bridge2
Lanes Under Bridge2

Inspection & Ownership

Last InspectionJanuary 2025
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour CriticalNot applicable
Structure NumberI00094027+03211

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.

Nearby Bridges