I-393 US 4 US202
Carrying I-393 US 4 US202 over I-93
0.4 MI. E. JCT US 3, Merrimack, New Hampshire
Inventory: FHWA NBI 2024 · last ETL August 2026
FHWA NBI record, refreshed with each annual release.
I-393 US 4 US202 in Merrimack, New Hampshire sits above 5% of rated New Hampshire bridges on inventory load rating (15 t), while its 1958 build year is earlier than 69% of Merrimack's recorded-year cohort (326 bridges).
I-393 US 4 US202 in Merrimack, New Hampshire is rated Poor in the FHWA's 2024 National Bridge Inventory. Built in 1958, 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 NH:005201520010800
INTERSTATE-ERA · STEEL · MULTI-SPAN · TIED-CTRL · HEAVY-ADT · LIGHT-LOAD · CAT-POOR
- INTERSTATE-ERA 1950–1979
- STEEL Steel
- MULTI-SPAN 2 spans
- TIED-CTRL Tied control
- HEAVY-ADT Heavy ADT
- LIGHT-LOAD Light 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: I-393 US 4 US202
The I-393 US 4 US202 bridge in Merrimack, New Hampshire carries I-393 US 4 US202 over I-93. It was built in 1958, making it 68 years old today. It was last reconstructed in 1981, extending its service life. The structure is built primarily of steel and spans 2 sections, stretching 50.9 meters (167 feet) end to end. Daily traffic averages 44,531 vehicles, placing it in the heavily-trafficked tier of New Hampshire bridges. It is owned and maintained by State Highway Agency.
The latest FHWA inspection records show a deck rating of 4/9, 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.
How I-393 US 4 US202 compares
Age against the county: built in 1958, earlier than 224 of Merrimack's 326 bridges with a recorded construction year (69%), 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).
I-393 US 4 US202 vs every rated New Hampshire bridge
Inventory load rating (metric tons), FHWA NBI, this state
15 Top 95% higher than 5% 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
- 1958
- Last Reconstructed
- 1981
- Material
- Steel
- Number of Spans
- 2
- Structure Length
- 50.9 m (167 ft)
- Deck Width
- 28.0 m (92 ft)
- Owner
- State Highway Agency
- Avg Daily Traffic
- 44,531 vehicles/day
- Structure Number
- 005201520010800
Condition Analysis
- • The deck (driving surface) is in poor condition (4/9), showing advanced deterioration on the inspecting agency's 0-9 scale.
- • 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 on file for this vintage.
Location
Data Source
FHWA National Bridge Inventory (NBI).
FHWA NBI Program ↗How to read this record
I-393 US 4 US202 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 I-393 US 4 US202 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 I-393 US 4 US202?
I-393 US 4 US202 in Merrimack, New Hampshire has a deck rating of 4/9, superstructure rating of 5/9, and substructure rating of 4/9 on the FHWA's 0–9 scale.
How often is I-393 US 4 US202 inspected?
I-393 US 4 US202'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 44,531 vehicles per day.
What does “structurally deficient” mean in older bridge reports?
FHWA retired that reported status beginning with the 2018 archive. I-393 US 4 US202 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 I-393 US 4 US202?
I-393 US 4 US202 has an NBI inventory load rating of 15.1 metric tons.
Who is responsible for maintaining I-393 US 4 US202?
I-393 US 4 US202 is owned and maintained by State Highway Agency.
How old is I-393 US 4 US202 and does age affect safety?
I-393 US 4 US202 was built in 1958, making it 68 years old and last reconstructed in 1981.
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.