I 90 over Manhattan South RD
FairGallatin County, Montana · 0.6M E Manhattan · Structure no. I00090289+02722
- Built
- 1964
- 61 years old
- Condition
- Fair
- inspected December 2023
- Type
- Stringer/Multi-beam or Girder
- Prestressed Concrete
- Length
- 163 ft
- 3 main spans
- Daily traffic
- 9,726
- 2023 count
- Owner
- State
- State Highway Agency
About this bridge
I 90 over Manhattan South RD is a prestressed concrete stringer/multi-beam or girder carrying I 90 over Manhattan South RD in Gallatin County, Montana. It was built in 1964, so it is 61 years old, older than the Montana average of 47 years.
The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 6 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.
It carries about 9,726 vehicles a day, roughly 12% of them trucks, projected to reach 10,990 by 2043. The structure is 163 ft (49.7 m) long and 41 ft wide. If it were closed, the detour would be 1.2 mi (2 km).
Location
Open in Google MapsCondition and inspection
The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.
| Component | Rating | Meaning |
|---|---|---|
| Deck | 7 Good | Some minor problems. |
| Superstructure | 7 Good | Some minor problems. |
| Substructure | 6 Satisfactory | Structural elements show some minor deterioration. |
Structure
Traffic and service
Ownership and planned work
Frequently asked questions
When was I 90 over Manhattan South RD built?
It was built in 1964, making it 61 years old in 2025.
What condition is I 90 over Manhattan South RD in?
The National Bridge Inventory rates it in fair condition. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. The last reported inspection was in December 2023.
How much traffic does I 90 over Manhattan South RD carry?
About 9,726 vehicles per day (2023 count), of which roughly 12% are trucks.
How long is I 90 over Manhattan South RD?
The structure is 163 ft (49.7 m) long with a longest span of 55 ft (16.8 m) and a deck 41 ft wide.
Who owns I 90 over Manhattan South RD?
It is owned by the State Highway Agency.