HWY 312
Carrying HWY 312 over RR
1M W POMPEY`S PILLAR, Yellowstone, Montana
Inventory: FHWA NBI 2024 · last ETL August 2026
FHWA NBI record, refreshed with each annual release.
HWY 312 in Yellowstone, Montana is rated Fair in the FHWA's 2024 National Bridge Inventory.
Built in 2004, it carries 3 rated components on the inspecting agency's 0-9 scale, and its weakest reported component scores 6. The lowest applicable rating sets the federal condition category, so this Fair result describes the weakest reported component rather than the structure as a whole. No NBI category is a closure decision or a live crossing-safety verdict.
NBI record plate
Structure MT:S00568000+00621
POST-2000 · PRESTRESS · MULTI-SPAN · DECK-LED · LOCAL-ADT · STANDARD-LOAD · CAT-FAIR
- POST-2000 2000+
- PRESTRESS Prestressed concrete
- MULTI-SPAN 3 spans
- DECK-LED Deck-led
- LOCAL-ADT Local ADT
- STANDARD-LOAD Standard load
- CAT-FAIR Fair
Inspection-sheet codes from this record’s year, material family, spans, controlling component, ADT, inventory load, and NBI category, not a live closure verdict.
Bridge Snapshot: HWY 312
The HWY 312 bridge in Yellowstone, Montana carries HWY 312 over RR. It was built in 2004, making it 22 years old today. The structure is built primarily of prestressed concrete continuous and spans 3 sections, stretching 97.0 meters (318 feet) end to end. Daily traffic averages 399 vehicles, placing it in the lower-traffic tier of Montana bridges. It is owned and maintained by State Highway Agency.
The latest FHWA inspection records show a deck rating of 6/9, superstructure at 7/9, substructure at 7/9. The weakest component sits in fair condition. All reported major components score above the Poor range.
How HWY 312 compares
Age against the county: built in 2004, earlier than 48 of Yellowstone's 290 bridges with a recorded construction year (17%), against a county median build year of 1976. This is one of the newer structures in its county.
Live comparison across Montana bridges with a recorded inventory load rating (5,144 of 5,224 rated).
HWY 312 vs every rated Montana bridge
Inventory load rating (metric tons), FHWA NBI, this state
23 Top 80% higher than 20% of 5,144 bridges
rated Montana bridges, bucketed by value
Each bar is a band; taller bars hold more bridges. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count and share, and where it sits relative to this entry.
Source FHWA National Bridge Inventory · August 2026
Condition Ratings
Full 0–9 scale + sufficiency-rating breakdown: how condition ratings work.
Reported 0–9 component ratings from the FHWA NBI. The highlighted component is the lowest reported input to this record’s current condition category; it is not a closure or live crossing-safety decision.
Yellowstone inventory by recorded NBI category
Exclusive Good/Fair/Poor bands across all 290 bridges in this county. Orthogonal to this structure's component profile above: a county catalog share, not a live crossing-safety verdict.
Structural Details
- Year Built
- 2004
- Material
- Prestressed Concrete Continuous
- Number of Spans
- 3
- Structure Length
- 97.0 m (318 ft)
- Deck Width
- 10.4 m (34 ft)
- Owner
- State Highway Agency
- Avg Daily Traffic
- 399 vehicles/day
- Structure Number
- S00568000+00621
Condition Analysis
- • The deck (driving surface) is in fair condition (6/9), with minor deterioration that may require routine maintenance.
- • The superstructure (beams and supports above the deck) is in good condition (7/9), showing no significant deterioration.
- • At 7/9, the substructure (piers and abutments) is in good shape and shows no significant wear.
Location
Data Source
FHWA National Bridge Inventory (NBI).
FHWA NBI Program ↗How to read this record
This page shows what the last federal inspection recorded, not whether HWY 312 is safe to cross today. Here is how to use it.
- NBI condition ratings reflect the latest record in this annual dataset, not a live status. Current routine inspection intervals are risk-based.
- Learn how the 0–9 condition scale and Good/Fair/Poor categories are defined. How condition ratings work
- Compare HWY 312 against other structures in Yellowstone and across Montana. Montana bridges
- Noticed visible damage or a safety concern? Report it to the agency that owns the bridge, or call 911 in an emergency. How to report a bridge
Condition codes come straight from the FHWA National Bridge Inventory and are not a real-time safety judgment. Only the owning agency, a state DOT, county, or other owner, can post, restrict, or close a bridge.
Frequently Asked Questions
What do the condition ratings mean for HWY 312?
HWY 312 in Yellowstone, Montana has a deck rating of 6/9, superstructure rating of 7/9, and substructure rating of 7/9 on the FHWA's 0–9 scale.
How often is HWY 312 inspected?
HWY 312's responsible agency sets its routine interval under FHWA's risk-based inspection rules; this page does not expose the scheduled interval. It carries about 399 vehicles per day.
What does “structurally deficient” mean in older bridge reports?
FHWA retired that reported status beginning with the 2018 archive. HWY 312 is currently shown as Fair condition from its component ratings; that category is not a live closure or safety decision.
What is the inventory load rating for HWY 312?
HWY 312 has an NBI inventory load rating of 22.7 metric tons.
Who is responsible for maintaining HWY 312?
HWY 312 is owned and maintained by State Highway Agency.
How old is HWY 312 and does age affect safety?
HWY 312 was built in 2004, making it 22 years old.
Disclaimer: Bridge condition data is from the FHWA NBI and reflects the last reported inspection. A Poor condition rating is not a live declaration that a bridge is closed or unsafe for travel. For current closure, posting, or safety information, contact the responsible transportation agency.
Share this inspection record
Send this source-bounded record or download its data card. An NBI condition category is not a closure or live crossing-safety verdict.
Every figure on PlainBridges is rendered directly from federal source data, no number is typed in by an editor. Component ratings, ADT, and condition category on this page are copied from the NBI record for this structure; no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of 2024 NBI release. NBI condition categories reflect the latest reported inventory record, not a live safety, closure, or travel decision.