FIR ROAD
Carrying FIR ROAD over DUTCH BILL CREEK
MONTE RIO, Sonoma, California
Data updated May 2026
FHWA NBI record, refreshed with each annual release.
Bridge Snapshot: FIR ROAD
The FIR ROAD bridge in Sonoma, California carries FIR ROAD over DUTCH BILL CREEK. It was built in 1974, making it 52 years old today. The structure is built primarily of steel and spans 5 sections, stretching 29.9 meters (98 feet) end to end. Daily traffic averages 300 vehicles, placing it in the lower-traffic tier of California bridges. It is owned and maintained by County Highway Agency.
The latest FHWA inspection records show a deck rating of 4/9, superstructure at 6/9, substructure at 5/9. The weakest component sits in poor condition. A component scored 4 or below, placing this bridge in the federal Poor condition category rather than declaring it unsafe or closed. Its NBI inventory load rating is 27.9 metric tons.
Sourced from the FHWA National Bridge Inventory. See our methodology for refresh cadence and NBI release vintage.
How FIR ROAD 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 How the historical reference is calculated.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
- 1974
- Material
- Steel
- Number of Spans
- 5
- Structure Length
- 29.9 m (98 ft)
- Deck Width
- 6.7 m (22 ft)
- Owner
- County Highway Agency
- Avg Daily Traffic
- 300 vehicles/day
- Structure Number
- 20C0393
Location
Data Source
FHWA National Bridge Inventory (NBI).
FHWA NBI Program ↗Condition Analysis
- • At 4/9, the deck (driving surface) is in poor shape, with advanced wear flagged for priority repair.
- • The superstructure (beams and supports above the deck) rates fair at 6/9, minor deterioration that routine maintenance should address.
- • At 5/9, the substructure (piers and abutments) shows fair condition, with minor wear flagged for upkeep.
How to read this record
FIR ROAD 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 FIR ROAD against other structures in Sonoma 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 FIR ROAD?
FIR ROAD in Sonoma, California has a deck rating of 4/9, superstructure rating of 6/9, and substructure rating of 5/9 on the FHWA's 0–9 scale.
How often is FIR ROAD inspected?
FIR ROAD'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 300 vehicles per day.
What does “structurally deficient” mean in older bridge reports?
FHWA retired that reported status beginning with the 2018 archive. FIR ROAD 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 FIR ROAD?
FIR ROAD has an NBI inventory load rating of 27.9 metric tons.
Who is responsible for maintaining FIR ROAD?
FIR ROAD is owned and maintained by County Highway Agency.
How old is FIR ROAD and does age affect safety?
FIR ROAD was built in 1974, making it 52 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.