BYRON HWY
Carrying BYRON HWY over CALIFORNIA AQUEDUCT
5.6 MI SOUTH OF SR 4, Contra Costa, California
Data updated May 2026
FHWA NBI record, refreshed with each annual release.
Bridge Snapshot: BYRON HWY
The BYRON HWY bridge in Contra Costa, California carries BYRON HWY over CALIFORNIA AQUEDUCT. It was built in 1964, making it 62 years old today. The structure is built primarily of concrete continuous and spans 5 sections, stretching 104.5 meters (343 feet) end to end. Daily traffic averages 8,387 vehicles, placing it in the moderately-trafficked tier of California bridges. It is owned and maintained by Other State Agencies.
The latest FHWA inspection records show a deck rating of 4/9, superstructure at 3/9, substructure at 7/9. 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 4.5 metric tons.
Sourced from the FHWA National Bridge Inventory. See our methodology for refresh cadence and NBI release vintage.
How BYRON HWY 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 How the historical reference is calculated.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
- 1964
- Material
- Concrete Continuous
- Number of Spans
- 5
- Structure Length
- 104.5 m (343 ft)
- Deck Width
- 10.4 m (34 ft)
- Owner
- Other State Agencies
- Avg Daily Traffic
- 8,387 vehicles/day
- Structure Number
- 28C0121
Location
Data Source
FHWA National Bridge Inventory (NBI).
FHWA NBI Program ↗Condition Analysis
- • The deck (driving surface) is in poor condition (4/9), showing advanced deterioration that may require priority repair.
- • The superstructure (beams and supports above the deck) is in poor condition (3/9), showing advanced deterioration that may require priority repair.
- • The substructure (piers and abutments) is in good condition (7/9), showing no significant deterioration.
How to read this record
BYRON HWY 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 BYRON HWY against other structures in Contra Costa 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 BYRON HWY?
BYRON HWY in Contra Costa, California has a deck rating of 4/9, superstructure rating of 3/9, and substructure rating of 7/9 on the FHWA's 0–9 scale.
How often is BYRON HWY inspected?
BYRON HWY'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 8,387 vehicles per day.
What does “structurally deficient” mean in older bridge reports?
FHWA retired that reported status beginning with the 2018 archive. BYRON HWY 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 BYRON HWY?
BYRON HWY has an NBI inventory load rating of 4.5 metric tons.
Who is responsible for maintaining BYRON HWY?
BYRON HWY is owned and maintained by Other State Agencies.
How old is BYRON HWY and does age affect safety?
BYRON HWY was built in 1964, making it 62 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.