FHWA NBI 2024 Inspection record Public-domain dataset

N. ST. CHARLES

Carrying N. ST. CHARLES over LEMHI RIVER

0.4 N. 0.3 E. SALMON, Lemhi, Idaho

Data updated May 2026

FHWA NBI record, refreshed with each annual release.

Poor
16 t Inventory load rating

Bridge Snapshot: N. ST. CHARLES

The N. ST. CHARLES bridge in Lemhi, Idaho carries N. ST. CHARLES over LEMHI RIVER. It was built in 1948, making it 78 years old today. It was last reconstructed in 1965, extending its service life. The structure is built primarily of prestressed concrete and spans 2 sections, stretching 24.1 meters (79 feet) end to end. Daily traffic averages 310 vehicles, placing it in the lower-traffic tier of Idaho bridges. It is owned and maintained by County Highway Agency.

The latest FHWA inspection records show a deck rating of 6/9, superstructure at 6/9, substructure at 4/9. The weakest component sits in poor condition. At least one major component here scores 4 or below, which produces a Poor condition classification under FHWA's current reporting rules. Its NBI inventory load rating is 16.3 metric tons.

Sourced from the FHWA National Bridge Inventory. See our methodology for refresh cadence and NBI release vintage.

How N. ST. CHARLES compares

▼ 15.0
Load rating vs Idaho average (31.3 t)
Bottom 7%
Lower load rating than 93% of Idaho bridges
73
Bridges in Lemhi · 6 in Poor condition
N. ST. CHARLES 16.3 t
Idaho average 31.3 t

Live comparison across Idaho.

Historical Sufficiency Rating

PlainBridge-computed
39.1 / 100 - historical 20–49.9 band
Structural adequacy /55
9.0
Serviceability /30
15.2
Essentiality /15
14.8
Special reductions
0

FHWA discontinued this calculated item; it does not determine current condition, funding eligibility, posting, or closure. How the historical reference is calculated.

Condition Ratings

Deck
6/9
Fair (5–6)
Superstructure
6/9
Fair (5–6)
Substructure
4/9
Poor (1–4)
Inventory Load Rating
16.3 t
NBI inventory level (metric tons)
Overall Condition
Poor

Full 0–9 scale + sufficiency-rating breakdown: how condition ratings work.

Structural Details

Year Built
1948
Last Reconstructed
1965
Material
Prestressed Concrete
Number of Spans
2
Structure Length
24.1 m (79 ft)
Deck Width
4.9 m (16 ft)
Owner
County Highway Agency
Avg Daily Traffic
310 vehicles/day
Structure Number
000000000032755

Condition Analysis

  • The deck (driving surface) rates fair at 6/9, minor deterioration that routine maintenance should address.
  • At 6/9, the superstructure (beams and supports above the deck) shows fair condition, with minor wear flagged for upkeep.
  • The substructure (piers and abutments) rates poor at 4/9, advanced deterioration that should be prioritized for repair.

How to read this record

N. ST. CHARLES is in the federal Poor condition category. That is a component-based result, not a closure order.

  • NBI condition ratings reflect the latest record in this annual dataset, not a live status. Current routine inspection intervals are risk-based.
  • Understand what Poor condition does and does not mean before drawing conclusions. Poor condition explained
  • Compare N. ST. CHARLES against other structures in Lemhi 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 N. ST. CHARLES?

N. ST. CHARLES in Lemhi, Idaho has a deck rating of 6/9, superstructure rating of 6/9, and substructure rating of 4/9 on the FHWA's 0–9 scale.

How often is N. ST. CHARLES inspected?

N. ST. CHARLES'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 310 vehicles per day.

What does “structurally deficient” mean in older bridge reports?

FHWA retired that reported status beginning with the 2018 archive. N. ST. CHARLES is currently shown as Poor condition from its component ratings; that category is not a live closure or safety decision.

What is the inventory load rating for N. ST. CHARLES?

N. ST. CHARLES has an NBI inventory load rating of 16.3 metric tons.

Who is responsible for maintaining N. ST. CHARLES?

N. ST. CHARLES is owned and maintained by County Highway Agency.

How old is N. ST. CHARLES and does age affect safety?

N. ST. CHARLES was built in 1948, making it 78 years old and last reconstructed in 1965.

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.

Data sourced from the Federal Highway Administration National Bridge Inventory. See our methodology for details. Retrieved and formatted by PlainBridges

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.