SOUTH ROAD
Carrying SOUTH ROAD over I-89
.8 MI E OF JCT US 202, Merrimack, New Hampshire
Inventory: FHWA NBI 2024 · last ETL August 2026
FHWA NBI record, refreshed with each annual release.
SOUTH ROAD in Merrimack, New Hampshire sits above 21% of rated New Hampshire bridges on inventory load rating (26 t), while its 1959 build year is earlier than 58% of Merrimack's recorded-year cohort (326 bridges).
SOUTH ROAD in Merrimack, New Hampshire is rated Fair in the FHWA's 2024 National Bridge Inventory. Built in 1959, it carries 3 rated components on the inspecting agency's 0-9 scale, and its weakest reported component scores 6. The lowest applicable rating sets the federal condition category, so this Fair 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 NH:012901230007700
INTERSTATE-ERA · STEEL · LONG-SPAN-RUN · DECK-LED · LOCAL-ADT · STANDARD-LOAD · CAT-FAIR
- INTERSTATE-ERA 1950–1979
- STEEL Steel
- LONG-SPAN-RUN 4 spans
- DECK-LED Deck-led
- LOCAL-ADT Local ADT
- STANDARD-LOAD Standard load
- CAT-FAIR Fair
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: SOUTH ROAD
The SOUTH ROAD bridge in Merrimack, New Hampshire carries SOUTH ROAD over I-89. It was built in 1959, making it 67 years old today. It was last reconstructed in 1991, extending its service life. The structure is built primarily of steel continuous and spans 4 sections, stretching 57.6 meters (189 feet) end to end. Daily traffic averages 90 vehicles, placing it in the lower-traffic tier of New Hampshire bridges. It is owned and maintained by State Highway Agency.
The latest FHWA inspection records show a deck rating of 6/9, superstructure at 7/9, substructure at 7/9. The weakest component sits in fair condition. All reported major components score above the Poor range.
How SOUTH ROAD compares
Age against the county: built in 1959, earlier than 189 of Merrimack's 326 bridges with a recorded construction year (58%), against a county median build year of 1966. Age is not a defect on its own, but it is the population from which future Poor ratings are drawn.
Live comparison across New Hampshire bridges with a recorded inventory load rating (2,540 of 2,542 rated).
SOUTH ROAD vs every rated New Hampshire bridge
Inventory load rating (metric tons), FHWA NBI, this state
26 Top 79% higher than 21% of 2,540 bridges
rated New Hampshire 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.
Merrimack inventory by recorded NBI category
Exclusive Good/Fair/Poor bands across all 326 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
- 1959
- Last Reconstructed
- 1991
- Material
- Steel Continuous
- Number of Spans
- 4
- Structure Length
- 57.6 m (189 ft)
- Deck Width
- 9.4 m (31 ft)
- Owner
- State Highway Agency
- Avg Daily Traffic
- 90 vehicles/day
- Structure Number
- 012901230007700
Condition Analysis
- • The deck (driving surface) is in fair condition (6/9), with minor deterioration that may require routine maintenance.
- • The superstructure (beams and supports above the deck) is in good condition (7/9), showing no significant deterioration.
- • The substructure (piers and abutments) rates good at 7/9, with no significant deterioration on file.
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 SOUTH ROAD 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 SOUTH ROAD against other structures in Merrimack and across New Hampshire. New Hampshire 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 ROAD?
SOUTH ROAD in Merrimack, New Hampshire has a deck rating of 6/9, superstructure rating of 7/9, and substructure rating of 7/9 on the FHWA's 0–9 scale.
How often is SOUTH ROAD inspected?
SOUTH 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 90 vehicles per day.
What does “structurally deficient” mean in older bridge reports?
FHWA retired that reported status beginning with the 2018 archive. SOUTH ROAD is currently shown as Fair condition from its component ratings; that category is not a live closure or safety decision.
What is the inventory load rating for SOUTH ROAD?
SOUTH ROAD has an NBI inventory load rating of 25.9 metric tons.
Who is responsible for maintaining SOUTH ROAD?
SOUTH ROAD is owned and maintained by State Highway Agency.
How old is SOUTH ROAD and does age affect safety?
SOUTH ROAD was built in 1959, making it 67 years old and last reconstructed in 1991.
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.