WESTSIDE ROAD
Carrying WESTSIDE ROAD over MILL CREEK
0.2 MI N FOREMAN LANE, Sonoma, California
Data updated May 2026
FHWA NBI record, refreshed with each annual release.
Bridge Snapshot: WESTSIDE ROAD
The WESTSIDE ROAD bridge in Sonoma, California carries WESTSIDE ROAD over MILL CREEK. It was built in 1961, making it 65 years old today. The structure is built primarily of concrete continuous and spans 3 sections, stretching 35.1 meters (115 feet) end to end. Daily traffic averages 3,200 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 6/9, superstructure at 7/9, substructure at 6/9. 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 20.1 metric tons.
Sourced from the FHWA National Bridge Inventory. See our methodology for refresh cadence and NBI release vintage.
How WESTSIDE 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 How the historical reference is calculated.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
- 1961
- Material
- Concrete Continuous
- Number of Spans
- 3
- Structure Length
- 35.1 m (115 ft)
- Deck Width
- 12.5 m (41 ft)
- Owner
- County Highway Agency
- Avg Daily Traffic
- 3,200 vehicles/day
- Structure Number
- 20C0071
Location
Data Source
FHWA National Bridge Inventory (NBI).
FHWA NBI Program ↗Condition Analysis
- • At 6/9, the deck (driving surface) shows fair condition, with minor wear flagged for upkeep.
- • The superstructure (beams and supports above the deck) is in good condition (7/9), showing no significant deterioration.
- • At 6/9, 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 WESTSIDE 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 WESTSIDE 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 WESTSIDE ROAD?
WESTSIDE ROAD in Sonoma, California has a deck rating of 6/9, superstructure rating of 7/9, and substructure rating of 6/9 on the FHWA's 0–9 scale.
How often is WESTSIDE ROAD inspected?
WESTSIDE 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 3,200 vehicles per day.
What does “structurally deficient” mean in older bridge reports?
FHWA retired that reported status beginning with the 2018 archive. WESTSIDE 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 WESTSIDE ROAD?
WESTSIDE ROAD has an NBI inventory load rating of 20.1 metric tons.
Who is responsible for maintaining WESTSIDE ROAD?
WESTSIDE ROAD is owned and maintained by County Highway Agency.
How old is WESTSIDE ROAD and does age affect safety?
WESTSIDE ROAD was built in 1961, making it 65 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.