Nh 11 over Mad River
Strafford County, New Hampshire · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- Nh 11 over Mad River in Strafford County, New Hampshire, is rated in fair condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the substructure, rated 6 (satisfactory condition) on the 0-9 scale.
- It was built in 1955, making it 70 years old at the 2025 inventory.
- It carries about 12,121 vehicles a day (traffic count year 2023).
- Its listed owner is the state highway agency.
- It is one of 41 of the 136 inventoried bridges in Strafford County rated fair (30.1%); 13 (9.6%) are rated poor.
- Its traffic status in the 2025 inventory is open, no restriction (NBI item 41).
- It was rated good in the 2024 inventory and is now fair (substructure 7 to 6).
- Its most recent inspection on record is dated May 2024, on a 24-month routine inspection cycle.
- A fair rating means the lowest-rated major component scores 5 or 6 on FHWA's 0-9 scale: some deterioration or minor section loss, but the structure is sound. It is the middle class, not a warning.
View this bridge on a map → (43.38691, -71.08172)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 7 | 7 | Good condition |
| Superstructure | 7 | 7 | Good condition |
| Substructure | 7 | 6 | Satisfactory condition |
Bridge details
| Structure | Concrete tee beam |
| Length | about 38 ft |
| Location | 1.7 Mi New Durham Tl |
| NBI structure number | 008400800012500 |
| Condition class | Fair |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | May 2024 |
| Inspection interval (item 91) | 24 months |
| Scour (item 113) | 8: foundations stable, scour above the top of the footing |
Source: FHWA National Bridge Inventory, 2025 data as reported by the New Hampshire department of transportation.
Busiest bridges in Strafford County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| Nh 16 Sp Tpk Ramp over NH125 | 2009 | 44,530 | Good |
| Nh 16 Sp Tpk over New Bellamy Lane | 1955 | 42,313 | Fair |
| US202 Nh 16 Sp Tpk over Ten Rod Road | 2012 | 41,600 | Good |
| US202 Nh 16 Sp Tpk over NH202A (walnut Street) | 1957 | 41,600 | Good |
| Nh 16 Sp Tpk over Cocheco River | 2010 | 39,653 | Good |
| Nh 16 Sp Tpk over Axehandle Brook | 1957 | 39,505 | Good |
All bridges nearby: Strafford County, NH bridge conditions · every bridge in Strafford County · New Hampshire bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.