MAIN ROAD
Carrying MAIN ROAD over LITTLE BUTANO CREEK
BUTANO ST PRK 0.4 MI IN, San Mateo, California
Data updated May 2026
FHWA NBI record, refreshed with each annual release.
Bridge Snapshot: MAIN ROAD
The MAIN ROAD bridge in San Mateo, California carries MAIN ROAD over LITTLE BUTANO CREEK. It was built in 1980, making it 46 years old today. The structure is built primarily of steel and spans 1 section, stretching 16.2 meters (53 feet) end to end. Daily traffic averages 70 vehicles, placing it in the lower-traffic tier of California bridges. It is owned and maintained by State Park/Forest/Reservation.
The latest FHWA inspection records show a deck rating of 7/9, superstructure at 4/9, substructure at 7/9. The weakest component sits in poor condition. A component scored 4 or below, placing this bridge in the federal Poor condition category rather than declaring it unsafe or closed. Its NBI inventory load rating is 20.4 metric tons.
Sourced from the FHWA National Bridge Inventory. See our methodology for refresh cadence and NBI release vintage.
How MAIN 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 How the historical reference is calculated.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
- 1980
- Material
- Steel
- Number of Spans
- 1
- Structure Length
- 16.2 m (53 ft)
- Deck Width
- 4.4 m (14 ft)
- Owner
- State Park/Forest/Reservation
- Avg Daily Traffic
- 70 vehicles/day
- Structure Number
- 35P0005
Location
Data Source
FHWA National Bridge Inventory (NBI).
FHWA NBI Program ↗Condition Analysis
- • At 7/9, the deck (driving surface) is in good shape and shows no significant wear.
- • At 4/9, the superstructure (beams and supports above the deck) is in poor shape, with advanced wear flagged for priority repair.
- • The substructure (piers and abutments) is in good condition (7/9), showing no significant deterioration.
How to read this record
MAIN ROAD 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 MAIN ROAD against other structures in San Mateo 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 MAIN ROAD?
MAIN ROAD in San Mateo, California has a deck rating of 7/9, superstructure rating of 4/9, and substructure rating of 7/9 on the FHWA's 0–9 scale.
How often is MAIN ROAD inspected?
MAIN 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 70 vehicles per day.
What does “structurally deficient” mean in older bridge reports?
FHWA retired that reported status beginning with the 2018 archive. MAIN ROAD 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 MAIN ROAD?
MAIN ROAD has an NBI inventory load rating of 20.4 metric tons.
Who is responsible for maintaining MAIN ROAD?
MAIN ROAD is owned and maintained by State Park/Forest/Reservation.
How old is MAIN ROAD and does age affect safety?
MAIN ROAD was built in 1980, making it 46 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.