US 4 MECHANIC ST
Carrying US 4 MECHANIC ST over MASCOMA RIVER
5.4 MI FROM HANOVER TL, Grafton, New Hampshire
Inventory: FHWA NBI 2024 · last ETL August 2026
FHWA NBI record, refreshed with each annual release.
US 4 MECHANIC ST in Grafton, New Hampshire sits above 43% of rated New Hampshire bridges on inventory load rating (33 t), while its 1977 build year is earlier than 33% of Grafton's recorded-year cohort (544 bridges).
US 4 MECHANIC ST in Grafton, New Hampshire is rated Poor in the FHWA's 2024 National Bridge Inventory. Built in 1977, 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:014401000011000
INTERSTATE-ERA · STEEL · SINGLE-SPAN · DECK-LED · HEAVY-ADT · STANDARD-LOAD · CAT-POOR
- INTERSTATE-ERA 1950–1979
- STEEL Steel
- SINGLE-SPAN Single span
- DECK-LED Deck-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: US 4 MECHANIC ST
The US 4 MECHANIC ST bridge in Grafton, New Hampshire carries US 4 MECHANIC ST over MASCOMA RIVER. It was built in 1977, making it 49 years old today. The structure is built primarily of steel and spans 1 section, stretching 27.1 meters (89 feet) end to end. Daily traffic averages 12,552 vehicles, placing it in the heavily-trafficked tier of New Hampshire bridges. It is owned and maintained by City/Municipal Highway Agency.
The latest FHWA inspection records show a deck rating of 4/9, superstructure at 7/9, substructure at 6/9. The weakest component sits in poor condition. At least one major component here scores 4 or below, which produces a Poor condition classification under FHWA's current reporting rules.
How US 4 MECHANIC ST compares
Age against the county: built in 1977, earlier than 180 of Grafton's 544 bridges with a recorded construction year (33%), against a county median build year of 1968. This is one of the newer structures in its county.
Live comparison across New Hampshire bridges with a recorded inventory load rating (2,540 of 2,542 rated).
US 4 MECHANIC ST vs every rated New Hampshire bridge
Inventory load rating (metric tons), FHWA NBI, this state
33 Top 57% higher than 43% 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.
Grafton inventory by recorded NBI category
Exclusive Good/Fair/Poor bands across all 544 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
- 1977
- Material
- Steel
- Number of Spans
- 1
- Structure Length
- 27.1 m (89 ft)
- Deck Width
- 22.1 m (73 ft)
- Owner
- City/Municipal Highway Agency
- Avg Daily Traffic
- 12,552 vehicles/day
- Structure Number
- 014401000011000
Condition Analysis
- • The deck (driving surface) rates poor at 4/9, with advanced deterioration recorded on the latest inspection.
- • The superstructure (beams and supports above the deck) is in good condition (7/9), showing no significant deterioration.
- • The substructure (piers and abutments) rates fair at 6/9, minor deterioration that routine maintenance should address.
Location
Data Source
FHWA National Bridge Inventory (NBI).
FHWA NBI Program ↗How to read this record
US 4 MECHANIC 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 US 4 MECHANIC ST against other structures in Grafton 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 US 4 MECHANIC ST?
US 4 MECHANIC ST in Grafton, New Hampshire has a deck rating of 4/9, superstructure rating of 7/9, and substructure rating of 6/9 on the FHWA's 0–9 scale.
How often is US 4 MECHANIC ST inspected?
US 4 MECHANIC 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 12,552 vehicles per day.
What does “structurally deficient” mean in older bridge reports?
FHWA retired that reported status beginning with the 2018 archive. US 4 MECHANIC 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 US 4 MECHANIC ST?
US 4 MECHANIC ST has an NBI inventory load rating of 32.8 metric tons.
Who is responsible for maintaining US 4 MECHANIC ST?
US 4 MECHANIC ST is owned and maintained by City/Municipal Highway Agency.
How old is US 4 MECHANIC ST and does age affect safety?
US 4 MECHANIC ST was built in 1977, making it 49 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.
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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.