WATMAUGH ROAD
Carrying WATMAUGH ROAD over SONOMA CREEK
0.3 MI WEST OF SR 12, Sonoma, California
Data updated May 2026
FHWA NBI record, refreshed with each annual release.
Bridge Snapshot: WATMAUGH ROAD
The WATMAUGH ROAD bridge in Sonoma, California carries WATMAUGH ROAD over SONOMA CREEK. It was built in 1929, making it 97 years old today. The structure is built primarily of steel and spans 1 section, stretching 51.8 meters (170 feet) end to end. Daily traffic averages 3,628 vehicles, placing it in the moderately-trafficked tier of California bridges. It is owned and maintained by County Highway Agency.
The latest FHWA inspection records show a deck rating of 5/9, superstructure at 5/9, substructure at 5/9. 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 13.3 metric tons.
Sourced from the FHWA National Bridge Inventory. See our methodology for refresh cadence and NBI release vintage.
How WATMAUGH 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 How the historical reference is calculated.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
- 1929
- Material
- Steel
- Number of Spans
- 1
- Structure Length
- 51.8 m (170 ft)
- Deck Width
- 7.2 m (24 ft)
- Owner
- County Highway Agency
- Avg Daily Traffic
- 3,628 vehicles/day
- Structure Number
- 20C0017
Location
Data Source
FHWA National Bridge Inventory (NBI).
FHWA NBI Program ↗Condition Analysis
- • The deck (driving surface) is in fair condition (5/9), with minor deterioration that may require routine maintenance.
- • The superstructure (beams and supports above the deck) rates fair at 5/9, 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
This page shows what the last federal inspection recorded, not whether WATMAUGH ROAD 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 WATMAUGH 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 WATMAUGH ROAD?
WATMAUGH ROAD in Sonoma, California has a deck rating of 5/9, superstructure rating of 5/9, and substructure rating of 5/9 on the FHWA's 0–9 scale.
How often is WATMAUGH ROAD inspected?
WATMAUGH 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 3,628 vehicles per day.
What does “structurally deficient” mean in older bridge reports?
FHWA retired that reported status beginning with the 2018 archive. WATMAUGH ROAD 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 WATMAUGH ROAD?
WATMAUGH ROAD has an NBI inventory load rating of 13.3 metric tons.
Who is responsible for maintaining WATMAUGH ROAD?
WATMAUGH ROAD is owned and maintained by County Highway Agency.
How old is WATMAUGH ROAD and does age affect safety?
WATMAUGH ROAD was built in 1929, making it 97 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.