STATE ROUTE 128
Carrying STATE ROUTE 128 over HOPPER SLOUGH
04-NAP-128-5.12, Napa, California
Data updated May 2026
FHWA NBI record, refreshed with each annual release.
Bridge Snapshot: STATE ROUTE 128
The STATE ROUTE 128 bridge in Napa, California carries STATE ROUTE 128 over HOPPER SLOUGH. It was built in 1921, making it 105 years old today. The structure is built primarily of concrete and spans 1 section, stretching 12.5 meters (41 feet) end to end. Daily traffic averages 2,075 vehicles, placing it in the moderately-trafficked tier of California bridges. It is owned and maintained by State Highway Agency.
The latest FHWA inspection records show a deck rating of 6/9, superstructure at 6/9, substructure at 3/9. The weakest component sits in poor condition. At least one major component here scores 4 or below, which produces a Poor condition classification under FHWA's current reporting rules. Its NBI inventory load rating is 22.0 metric tons.
Sourced from the FHWA National Bridge Inventory. See our methodology for refresh cadence and NBI release vintage.
How STATE ROUTE 128 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 How the historical reference is calculated.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
- 1921
- Material
- Concrete
- Number of Spans
- 1
- Structure Length
- 12.5 m (41 ft)
- Deck Width
- 6.9 m (23 ft)
- Owner
- State Highway Agency
- Avg Daily Traffic
- 2,075 vehicles/day
- Structure Number
- 21 0019
Location
Data Source
FHWA National Bridge Inventory (NBI).
FHWA NBI Program ↗Condition Analysis
- • The deck (driving surface) rates fair at 6/9, minor deterioration that routine maintenance should address.
- • At 6/9, the superstructure (beams and supports above the deck) shows fair condition, with minor wear flagged for upkeep.
- • At 3/9, the substructure (piers and abutments) is in poor shape, with advanced wear flagged for priority repair.
How to read this record
STATE ROUTE 128 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 STATE ROUTE 128 against other structures in Napa 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 128?
STATE ROUTE 128 in Napa, California has a deck rating of 6/9, superstructure rating of 6/9, and substructure rating of 3/9 on the FHWA's 0–9 scale.
How often is STATE ROUTE 128 inspected?
STATE ROUTE 128'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 2,075 vehicles per day.
What does “structurally deficient” mean in older bridge reports?
FHWA retired that reported status beginning with the 2018 archive. STATE ROUTE 128 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 STATE ROUTE 128?
STATE ROUTE 128 has an NBI inventory load rating of 22.0 metric tons.
Who is responsible for maintaining STATE ROUTE 128?
STATE ROUTE 128 is owned and maintained by State Highway Agency.
How old is STATE ROUTE 128 and does age affect safety?
STATE ROUTE 128 was built in 1921, making it 105 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.