Blackwellsmills Rd over Millstone River
Somerset County, New Jersey · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- Blackwellsmills Rd over Millstone River in Somerset County, New Jersey, is rated in fair condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the deck, rated 6 (satisfactory condition) on the 0-9 scale.
- It was built in 1994, making it 31 years old at the 2025 inventory.
- It carries about 4,542 vehicles a day (traffic count year 2023).
- Its listed owner is the county highway agency.
- It is one of 233 of the 397 inventoried bridges in Somerset County rated fair (58.7%); 34 (8.6%) are rated poor.
- Its traffic status in the 2025 inventory is open, no restriction (NBI item 41).
- Its condition class and component ratings are unchanged from the 2024 inventory.
- Its most recent inspection on record is dated October 2023, 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 → (40.47472, -74.57617)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 6 | 6 | Satisfactory condition |
| Superstructure | 8 | 8 | Very good condition |
| Substructure | 7 | 7 | Good condition |
Bridge details
| Structure | Continuous steel stringer or multi-beam girder |
| Length | about 108 ft |
| Location | at River Rd Intersection |
| NBI structure number | 18G0404 |
| Condition class | Fair |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | October 2023 |
| 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 Jersey department of transportation.
Busiest bridges in Somerset County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| Route I-287 over Canal Rd D&r Raritan&rr | 1960 | 159,760 | Fair |
| I-287 over NJT (Raritan Valley) | 1960 | 148,249 | Fair |
| I-287 over Main St (CR 533) | 1960 | 138,097 | Fair |
| I-287 over Sky Brook | 1959 | 122,240 | Fair |
| Route I-287 S.B. over Elizabeth Ave (CR 621) | 1961 | 120,175 | Fair |
| I-78 over Corys Brook | 1965 | 105,645 | Fair |
All bridges nearby: Somerset County, NJ bridge conditions · every bridge in Somerset County · New Jersey bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.