ISLAND RD
Carrying ISLAND RD over ATLANTIC OCEAN
MAINLAND-SPRUCE HEAD IS., Knox, Maine
Inventory: FHWA NBI 2024 · last ETL August 2026
FHWA NBI record, refreshed with each annual release.
ISLAND RD in Knox, Maine sits above 77% of rated Maine bridges on inventory load rating (48 t), while its 2010 build year is earlier than 23% of Knox's recorded-year cohort (53 bridges).
ISLAND RD in Knox, Maine is rated Good in the FHWA's 2024 National Bridge Inventory. Built in 2010, it carries 3 rated components on the inspecting agency's 0-9 scale, and its weakest reported component scores 8. The lowest applicable rating sets the federal condition category, so this Good result describes the weakest reported component rather than the structure as a whole. No NBI category is a closure decision or a live crossing-safety verdict.
NBI record plate
Structure ME:5578
POST-2000 · PRESTRESS · SINGLE-SPAN · TIED-CTRL · LOCAL-ADT · HEAVY-LOAD · CAT-GOOD
- POST-2000 2000+
- PRESTRESS Prestressed concrete
- SINGLE-SPAN Single span
- TIED-CTRL Tied control
- LOCAL-ADT Local ADT
- HEAVY-LOAD Heavy load
- CAT-GOOD Good
Inspection-sheet codes from this record’s year, material family, spans, controlling component, ADT, inventory load, and NBI category, not a live closure verdict.
Bridge Snapshot: ISLAND RD
The ISLAND RD bridge in Knox, Maine carries ISLAND RD over ATLANTIC OCEAN. It was built in 2010, making it 16 years old today. The structure is built primarily of prestressed concrete and spans 1 section, stretching 31.4 meters (103 feet) end to end. Daily traffic averages 900 vehicles, placing it in the lower-traffic tier of Maine bridges. It is owned and maintained by State Highway Agency.
The latest FHWA inspection records show a deck rating of 8/9, superstructure at 8/9, substructure at 8/9. The weakest component sits in good condition. None of this bridge's reported major components fall into the Poor condition range.
How ISLAND RD compares
Age against the county: built in 2010, earlier than 12 of Knox's 53 bridges with a recorded construction year (23%), against a county median build year of 1959. This is one of the newer structures in its county.
Live comparison across Maine bridges with a recorded inventory load rating (2,518 rated).
ISLAND RD vs every rated Maine bridge
Inventory load rating (metric tons), FHWA NBI, this state
48 Top 23% higher than 77% of 2,518 bridges
rated Maine bridges, bucketed by value
Each bar is a band; taller bars hold more bridges. The dashed line + filled bar mark this entry. Hover or tap any bar for its full count and share, and where it sits relative to this entry.
Source FHWA National Bridge Inventory · August 2026
Condition Ratings
Full 0–9 scale + sufficiency-rating breakdown: how condition ratings work.
Reported 0–9 component ratings from the FHWA NBI. The highlighted component is the lowest reported input to this record’s current condition category; it is not a closure or live crossing-safety decision.
Knox inventory by recorded NBI category
Exclusive Good/Fair/Poor bands across all 53 bridges in this county. Orthogonal to this structure's component profile above: a county catalog share, not a live crossing-safety verdict.
Structural Details
- Year Built
- 2010
- Material
- Prestressed Concrete
- Number of Spans
- 1
- Structure Length
- 31.4 m (103 ft)
- Deck Width
- 8.5 m (28 ft)
- Owner
- State Highway Agency
- Avg Daily Traffic
- 900 vehicles/day
- Structure Number
- 5578
Condition Analysis
- • The deck (driving surface) rates good at 8/9, with no significant deterioration on file.
- • The superstructure (beams and supports above the deck) rates good at 8/9, with no significant deterioration on file.
- • The substructure (piers and abutments) is in good condition (8/9), showing no significant deterioration.
Location
Data Source
FHWA National Bridge Inventory (NBI).
FHWA NBI Program ↗How to read this record
This page shows what the last federal inspection recorded, not whether ISLAND RD is safe to cross today. Here is how to use it.
- NBI condition ratings reflect the latest record in this annual dataset, not a live status. Current routine inspection intervals are risk-based.
- Learn how the 0–9 condition scale and Good/Fair/Poor categories are defined. How condition ratings work
- Compare ISLAND RD against other structures in Knox and across Maine. Maine 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 ISLAND RD?
ISLAND RD in Knox, Maine has a deck rating of 8/9, superstructure rating of 8/9, and substructure rating of 8/9 on the FHWA's 0–9 scale.
How often is ISLAND RD inspected?
ISLAND RD'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 900 vehicles per day.
What does “structurally deficient” mean in older bridge reports?
FHWA retired that reported status beginning with the 2018 archive. ISLAND RD is currently shown as Good condition from its component ratings; that category is not a live closure or safety decision.
What is the inventory load rating for ISLAND RD?
ISLAND RD has an NBI inventory load rating of 47.6 metric tons.
Who is responsible for maintaining ISLAND RD?
ISLAND RD is owned and maintained by State Highway Agency.
How old is ISLAND RD and does age affect safety?
ISLAND RD was built in 2010, making it 16 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.
Share this inspection record
Send this source-bounded record or download its data card. An NBI condition category is not a closure or live crossing-safety verdict.
Every figure on PlainBridges is rendered directly from federal source data, no number is typed in by an editor. Component ratings, ADT, and condition category on this page are copied from the NBI record for this structure; no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. Data current as of 2024 NBI release. NBI condition categories reflect the latest reported inventory record, not a live safety, closure, or travel decision.