STATE ROUTE 99
Carrying STATE ROUTE 99 over CAT TAIL SLOUGH
03-BUT-099-5.34, Butte, California
Data updated May 2026
FHWA NBI record, refreshed with each annual release.
Bridge Snapshot: STATE ROUTE 99
The STATE ROUTE 99 bridge in Butte, California carries STATE ROUTE 99 over CAT TAIL SLOUGH. It was built in 1910, making it 116 years old today. It was last reconstructed in 1939, extending its service life. The structure is built primarily of concrete and spans 1 section, stretching 6.3 meters (21 feet) end to end. Daily traffic averages 13,400 vehicles, placing it in the heavily-trafficked tier of California bridges. It is owned and maintained by State Highway Agency.
The latest FHWA inspection records show a deck rating of 7/9, superstructure at 5/9, substructure at 7/9. The weakest component sits in fair condition. None of this bridge's reported major components fall into the Poor condition range. Its NBI inventory load rating is 24.3 metric tons.
Sourced from the FHWA National Bridge Inventory. See our methodology for refresh cadence and NBI release vintage.
How STATE ROUTE 99 compares
Live comparison across California.
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 How the historical reference is calculated.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
- 1910
- Last Reconstructed
- 1939
- Material
- Concrete
- Number of Spans
- 1
- Structure Length
- 6.3 m (21 ft)
- Deck Width
- 11.7 m (38 ft)
- Owner
- State Highway Agency
- Avg Daily Traffic
- 13,400 vehicles/day
- Structure Number
- 12 0001
Location
Data Source
FHWA National Bridge Inventory (NBI).
FHWA NBI Program ↗Condition Analysis
- • The deck (driving surface) rates good at 7/9, with no significant deterioration on file.
- • At 5/9, the superstructure (beams and supports above the deck) shows fair condition, with minor wear flagged for upkeep.
- • 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 STATE ROUTE 99 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 STATE ROUTE 99 against other structures in Butte and across California. California 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 STATE ROUTE 99?
STATE ROUTE 99 in Butte, California has a deck rating of 7/9, superstructure rating of 5/9, and substructure rating of 7/9 on the FHWA's 0–9 scale.
How often is STATE ROUTE 99 inspected?
STATE ROUTE 99'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 13,400 vehicles per day.
What does “structurally deficient” mean in older bridge reports?
FHWA retired that reported status beginning with the 2018 archive. STATE ROUTE 99 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 STATE ROUTE 99?
STATE ROUTE 99 has an NBI inventory load rating of 24.3 metric tons.
Who is responsible for maintaining STATE ROUTE 99?
STATE ROUTE 99 is owned and maintained by State Highway Agency.
How old is STATE ROUTE 99 and does age affect safety?
STATE ROUTE 99 was built in 1910, making it 116 years old and last reconstructed in 1939.
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.