ST 9 BOYLSTON ST
Carrying ST 9 BOYLSTON ST over TR GREEN LINE D
2.3 KM ELY RT 128, Middlesex, Massachusetts
Inventory: FHWA NBI 2024 · last ETL August 2026
FHWA NBI record, refreshed with each annual release.
ST 9 BOYLSTON ST in Middlesex, Massachusetts sits above 19% of rated Massachusetts bridges on inventory load rating (28 t), while its 1905 build year is earlier than 89% of Middlesex's recorded-year cohort (818 bridges).
ST 9 BOYLSTON ST in Middlesex, Massachusetts is rated Poor in the FHWA's 2024 National Bridge Inventory. Built in 1905, it carries 3 rated components on the inspecting agency's 0-9 scale, and its weakest reported component scores 4. The lowest applicable rating sets the federal condition category, so this Poor 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 MA:N120402EEDOTNBI
PRE-1950 · STEEL · SINGLE-SPAN · SUPER-LED · HEAVY-ADT · STANDARD-LOAD · CAT-POOR
- PRE-1950 Pre-1950
- STEEL Steel
- SINGLE-SPAN Single span
- SUPER-LED Superstructure-led
- HEAVY-ADT Heavy ADT
- STANDARD-LOAD Standard load
- CAT-POOR Poor
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: ST 9 BOYLSTON ST
The ST 9 BOYLSTON ST bridge in Middlesex, Massachusetts carries ST 9 BOYLSTON ST over TR GREEN LINE D. It was built in 1905, making it 121 years old today. It was last reconstructed in 1960, extending its service life. The structure is built primarily of steel and spans 1 section, stretching 17.1 meters (56 feet) end to end. Daily traffic averages 96,206 vehicles, placing it in the heavily-trafficked tier of Massachusetts bridges. It is owned and maintained by State Highway Agency.
The latest FHWA inspection records show a deck rating of 5/9, superstructure at 4/9, substructure at 5/9. 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.
How ST 9 BOYLSTON ST compares
Age against the county: built in 1905, earlier than 726 of Middlesex's 818 bridges with a recorded construction year (89%), against a county median build year of 1960. Age is not a defect on its own, but it is the population from which future Poor ratings are drawn.
Live comparison across Massachusetts bridges with a recorded inventory load rating (5,295 rated).
ST 9 BOYLSTON ST vs every rated Massachusetts bridge
Inventory load rating (metric tons), FHWA NBI, this state
28 Top 81% higher than 19% of 5,295 bridges
rated Massachusetts 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.
Middlesex inventory by recorded NBI category
Exclusive Good/Fair/Poor bands across all 818 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
- 1905
- Last Reconstructed
- 1960
- Material
- Steel
- Number of Spans
- 1
- Structure Length
- 17.1 m (56 ft)
- Deck Width
- 27.4 m (90 ft)
- Owner
- State Highway Agency
- Avg Daily Traffic
- 96,206 vehicles/day
- Structure Number
- N120402EEDOTNBI
Condition Analysis
- • The deck (driving surface) rates fair at 5/9, minor deterioration that routine maintenance should address.
- • The superstructure (beams and supports above the deck) is in poor condition (4/9), showing advanced deterioration on the inspecting agency's 0-9 scale.
- • At 5/9, the substructure (piers and abutments) shows fair condition, with minor wear flagged for upkeep.
Location
Data Source
FHWA National Bridge Inventory (NBI).
FHWA NBI Program ↗How to read this record
ST 9 BOYLSTON ST 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 ST 9 BOYLSTON ST against other structures in Middlesex and across Massachusetts. Massachusetts 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 ST 9 BOYLSTON ST?
ST 9 BOYLSTON ST in Middlesex, Massachusetts has a deck rating of 5/9, superstructure rating of 4/9, and substructure rating of 5/9 on the FHWA's 0–9 scale.
How often is ST 9 BOYLSTON ST inspected?
ST 9 BOYLSTON ST'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 96,206 vehicles per day.
What does “structurally deficient” mean in older bridge reports?
FHWA retired that reported status beginning with the 2018 archive. ST 9 BOYLSTON ST 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 ST 9 BOYLSTON ST?
ST 9 BOYLSTON ST has an NBI inventory load rating of 28.3 metric tons.
Who is responsible for maintaining ST 9 BOYLSTON ST?
ST 9 BOYLSTON ST is owned and maintained by State Highway Agency.
How old is ST 9 BOYLSTON ST and does age affect safety?
ST 9 BOYLSTON ST was built in 1905, making it 121 years old and last reconstructed in 1960.
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.