3700 NORTH
Carrying 3700 NORTH over BIG LOST RIVER
1.2 E. DARLINGTON, Custer, Idaho
Data updated May 2026
FHWA NBI record, refreshed with each annual release.
Bridge Snapshot: 3700 NORTH
The 3700 NORTH bridge in Custer, Idaho carries 3700 NORTH over BIG LOST RIVER. It was built in 2010, making it 16 years old today. The structure is built primarily of prestressed concrete continuous and spans 1 section, stretching 26.5 meters (87 feet) end to end. Daily traffic averages 50 vehicles, placing it in the lower-traffic tier of Idaho bridges. It is owned and maintained by Other Local Agencies.
The latest FHWA inspection records show a deck rating of 7/9, superstructure at 8/9, substructure at 7/9. The weakest component sits in good condition. None of this bridge's reported major components fall into the Poor condition range. Its NBI inventory load rating is 38.1 metric tons.
Sourced from the FHWA National Bridge Inventory. See our methodology for refresh cadence and NBI release vintage.
How 3700 NORTH 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 How the historical reference is calculated.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
- 2010
- Material
- Prestressed Concrete Continuous
- Number of Spans
- 1
- Structure Length
- 26.5 m (87 ft)
- Deck Width
- 7.1 m (23 ft)
- Owner
- Other Local Agencies
- Avg Daily Traffic
- 50 vehicles/day
- Structure Number
- 000000000031726
Location
Data Source
FHWA National Bridge Inventory (NBI).
FHWA NBI Program ↗Condition Analysis
- • At 7/9, the deck (driving surface) is in good shape and shows no significant wear.
- • The superstructure (beams and supports above the deck) is in good condition (8/9), showing no significant deterioration.
- • The substructure (piers and abutments) rates good at 7/9, with no significant deterioration on file.
How to read this record
This page shows what the last federal inspection recorded, not whether 3700 NORTH 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 3700 NORTH against other structures in Custer 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 3700 NORTH?
3700 NORTH in Custer, Idaho has a deck rating of 7/9, superstructure rating of 8/9, and substructure rating of 7/9 on the FHWA's 0–9 scale.
How often is 3700 NORTH inspected?
3700 NORTH'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 50 vehicles per day.
What does “structurally deficient” mean in older bridge reports?
FHWA retired that reported status beginning with the 2018 archive. 3700 NORTH is currently shown as Good condition from its component ratings; that category is not a live closure or safety decision.
What is the inventory load rating for 3700 NORTH?
3700 NORTH has an NBI inventory load rating of 38.1 metric tons.
Who is responsible for maintaining 3700 NORTH?
3700 NORTH is owned and maintained by Other Local Agencies.
How old is 3700 NORTH and does age affect safety?
3700 NORTH was built in 2010, making it 16 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.