SOUTH TONGASS HWY
Carrying SOUTH TONGASS HWY over WATER ST VIADUCT
MILE POINT 1.7, Ketchikan Gateway, Alaska
Data updated May 2026
FHWA NBI record, refreshed with each annual release.
Bridge Snapshot: SOUTH TONGASS HWY
The SOUTH TONGASS HWY bridge in Ketchikan Gateway, Alaska carries SOUTH TONGASS HWY over WATER ST VIADUCT. It was built in 1955, making it 71 years old today. The structure is built primarily of prestressed concrete and spans 81 sections, stretching 495.0 meters (1624 feet) end to end. Daily traffic averages 14,046 vehicles, placing it in the heavily-trafficked tier of Alaska bridges. It is owned and maintained by State Highway Agency.
The latest FHWA inspection records show a deck rating of 7/9, superstructure at 5/9, substructure at 4/9. 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 27.1 metric tons.
Sourced from the FHWA National Bridge Inventory. See our methodology for refresh cadence and NBI release vintage.
How SOUTH TONGASS HWY compares
Live comparison across Alaska.
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 How the historical reference is calculated.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
- 1955
- Material
- Prestressed Concrete
- Number of Spans
- 81
- Structure Length
- 495.0 m (1624 ft)
- Deck Width
- 16.2 m (53 ft)
- Owner
- State Highway Agency
- Avg Daily Traffic
- 14,046 vehicles/day
- Structure Number
- 0797
Location
Data Source
FHWA National Bridge Inventory (NBI).
FHWA NBI Program ↗Condition Analysis
- • The deck (driving surface) is in good condition (7/9), showing no significant deterioration.
- • The superstructure (beams and supports above the deck) is in fair condition (5/9), with minor deterioration that may require routine maintenance.
- • At 4/9, the substructure (piers and abutments) is in poor shape, with advanced wear flagged for priority repair.
How to read this record
SOUTH TONGASS 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 SOUTH TONGASS HWY against other structures in Ketchikan Gateway and across Alaska. Alaska 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 SOUTH TONGASS HWY?
SOUTH TONGASS HWY in Ketchikan Gateway, Alaska has a deck rating of 7/9, superstructure rating of 5/9, and substructure rating of 4/9 on the FHWA's 0–9 scale.
How often is SOUTH TONGASS HWY inspected?
SOUTH TONGASS 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 14,046 vehicles per day.
What does “structurally deficient” mean in older bridge reports?
FHWA retired that reported status beginning with the 2018 archive. SOUTH TONGASS 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 SOUTH TONGASS HWY?
SOUTH TONGASS HWY has an NBI inventory load rating of 27.1 metric tons.
Who is responsible for maintaining SOUTH TONGASS HWY?
SOUTH TONGASS HWY is owned and maintained by State Highway Agency.
How old is SOUTH TONGASS HWY and does age affect safety?
SOUTH TONGASS HWY was built in 1955, making it 71 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.