US 20B
Carrying US 20B over HENRY'S FK. SNAKE RIVER
IN ST ANTHONY, Fremont, Idaho
Data updated May 2026
FHWA NBI record, refreshed with each annual release.
Bridge Snapshot: US 20B
The US 20B bridge in Fremont, Idaho carries US 20B over HENRY'S FK. SNAKE RIVER. It was built in 1965, making it 61 years old today. The structure is built primarily of steel and spans 1 section, stretching 31.7 meters (104 feet) end to end. Daily traffic averages 11,000 vehicles, placing it in the heavily-trafficked tier of Idaho bridges. It is owned and maintained by State Highway Agency.
The latest FHWA inspection records show a deck rating of 6/9, superstructure at 6/9, substructure at 6/9. The weakest component sits in fair condition. No reported major component scores in the Poor range under the current federal condition thresholds. Its NBI inventory load rating is 49.0 metric tons.
Sourced from the FHWA National Bridge Inventory. See our methodology for refresh cadence and NBI release vintage.
How US 20B compares
Live comparison across Idaho.
Historical Sufficiency Rating
PlainBridge-computedFHWA discontinued this calculated item; it does not determine current condition, funding eligibility, posting, or closure. How the historical reference is calculated.
Condition Ratings
Full 0–9 scale + sufficiency-rating breakdown: how condition ratings work.
Structural Details
- Year Built
- 1965
- Material
- Steel
- Number of Spans
- 1
- Structure Length
- 31.7 m (104 ft)
- Deck Width
- 20.1 m (66 ft)
- Owner
- State Highway Agency
- Avg Daily Traffic
- 11,000 vehicles/day
- Structure Number
- 000000000012730
Location
Data Source
FHWA National Bridge Inventory (NBI).
FHWA NBI Program ↗Condition Analysis
- • The deck (driving surface) rates fair at 6/9, minor deterioration that routine maintenance should address.
- • The superstructure (beams and supports above the deck) rates fair at 6/9, minor deterioration that routine maintenance should address.
- • At 6/9, the substructure (piers and abutments) shows fair condition, with minor wear flagged for upkeep.
How to read this record
This page shows what the last federal inspection recorded, not whether US 20B 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 US 20B against other structures in Fremont and across Idaho. Idaho 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 US 20B?
US 20B in Fremont, Idaho has a deck rating of 6/9, superstructure rating of 6/9, and substructure rating of 6/9 on the FHWA's 0–9 scale.
How often is US 20B inspected?
US 20B'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 11,000 vehicles per day.
What does “structurally deficient” mean in older bridge reports?
FHWA retired that reported status beginning with the 2018 archive. US 20B 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 US 20B?
US 20B has an NBI inventory load rating of 49.0 metric tons.
Who is responsible for maintaining US 20B?
US 20B is owned and maintained by State Highway Agency.
How old is US 20B and does age affect safety?
US 20B was built in 1965, making it 61 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.
Every figure on PlainBridge is rendered directly from federal source data, no number is typed in by an editor. This page draws directly on federal source data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.