US 12 over RR
GoodLewis and Clark County, Montana · 3M E Helena · Structure no. P00008047+09781
- Built
- 1978
- 47 years old
- Condition
- Good
- inspected May 2023
- Type
- Stringer/Multi-beam or Girder
- Prestressed Concrete
- Length
- 276 ft
- 3 main spans
- Daily traffic
- 19,327
- 2023 count
- Owner
- State
- State Highway Agency
About this bridge
US 12 over RR is a prestressed concrete stringer/multi-beam or girder carrying US 12 over RR in Lewis and Clark County, Montana. It was built in 1978, so it is 47 years old, younger than the Montana average of 47 years.
The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 7 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.
It carries about 19,327 vehicles a day, roughly 1% of them trucks, projected to reach 20,293 by 2043. The structure is 276 ft (84.1 m) long and 99 ft wide. If it were closed, the detour would be 1.2 mi (2 km).
Location
Open in Google MapsCondition and inspection
All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.
| Component | Rating | Meaning |
|---|---|---|
| Deck | 8 Very Good | No problems noted. |
| Superstructure | 8 Very Good | No problems noted. |
| Substructure | 7 Good | Some minor problems. |
Structure
Traffic and service
Ownership and planned work
Frequently asked questions
When was US 12 over RR built?
It was built in 1978, making it 47 years old in 2025.
What condition is US 12 over RR in?
The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in May 2023.
How much traffic does US 12 over RR carry?
About 19,327 vehicles per day (2023 count), of which roughly 1% are trucks.
How long is US 12 over RR?
The structure is 276 ft (84.1 m) long with a longest span of 108 ft (32.9 m) and a deck 99 ft wide.
Who owns US 12 over RR?
It is owned by the State Highway Agency.