U.S. HIGHWAY 101
Carrying U.S. HIGHWAY 101 over CORTE MADERA CR & EB SFD
04-MRN-101-8.47-LKSP, Marin, California
Data updated May 2026
FHWA NBI record, refreshed with each annual release.
Bridge Snapshot: U.S. HIGHWAY 101
The U.S. HIGHWAY 101 bridge in Marin, California carries U.S. HIGHWAY 101 over CORTE MADERA CR & EB SFD. It was built in 1959, making it 67 years old today. It was last reconstructed in 2004, extending its service life. The structure is built primarily of concrete continuous and spans 11 sections, stretching 502.3 meters (1648 feet) end to end. Daily traffic averages 19,700 vehicles, placing it in the heavily-trafficked tier of California bridges. It is owned and maintained by State Highway Agency.
The latest FHWA inspection records show a deck rating of 4/9, superstructure at 7/9, substructure at 6/9. The weakest component sits in poor condition. Because at least one major component scores 4 or lower, this bridge falls in FHWA's Poor condition category. That category is not a closure order. Its NBI inventory load rating is 33.0 metric tons.
Sourced from the FHWA National Bridge Inventory. See our methodology for refresh cadence and NBI release vintage.
How U.S. HIGHWAY 101 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 How the historical reference is calculated.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
- 1959
- Last Reconstructed
- 2004
- Material
- Concrete Continuous
- Number of Spans
- 11
- Structure Length
- 502.3 m (1648 ft)
- Deck Width
- 11.2 m (37 ft)
- Owner
- State Highway Agency
- Avg Daily Traffic
- 19,700 vehicles/day
- Structure Number
- 27 0008K
Location
Data Source
FHWA National Bridge Inventory (NBI).
FHWA NBI Program ↗Condition Analysis
- • The deck (driving surface) rates poor at 4/9, advanced deterioration that should be prioritized for repair.
- • The superstructure (beams and supports above the deck) is in good condition (7/9), showing no significant deterioration.
- • The substructure (piers and abutments) is in fair condition (6/9), with minor deterioration that may require routine maintenance.
How to read this record
U.S. HIGHWAY 101 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 U.S. HIGHWAY 101 against other structures in Marin 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 U.S. HIGHWAY 101?
U.S. HIGHWAY 101 in Marin, California has a deck rating of 4/9, superstructure rating of 7/9, and substructure rating of 6/9 on the FHWA's 0–9 scale.
How often is U.S. HIGHWAY 101 inspected?
U.S. HIGHWAY 101'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 19,700 vehicles per day.
What does “structurally deficient” mean in older bridge reports?
FHWA retired that reported status beginning with the 2018 archive. U.S. HIGHWAY 101 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 U.S. HIGHWAY 101?
U.S. HIGHWAY 101 has an NBI inventory load rating of 33.0 metric tons.
Who is responsible for maintaining U.S. HIGHWAY 101?
U.S. HIGHWAY 101 is owned and maintained by State Highway Agency.
How old is U.S. HIGHWAY 101 and does age affect safety?
U.S. HIGHWAY 101 was built in 1959, making it 67 years old and last reconstructed in 2004.
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.