Irr Bia Rte 4178 over Irrigation Canal
San Juan County, New Mexico · rated Good in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- Irr Bia Rte 4178 over Irrigation Canal in San Juan County, New Mexico, is rated in good condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the culvert, rated 7 (good condition) on the 0-9 scale.
- It was built in 1992, making it 33 years old at the 2025 inventory.
- It carries about 1,000 vehicles a day (traffic count year 2023).
- It is one of 60 of the 174 inventoried bridges in San Juan County rated good (34.5%); 10 (5.7%) 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 April 2023, on a 24-month routine inspection cycle.
- A good rating means every major component - deck, superstructure, substructure, or culvert - is rated 7 or higher on FHWA's 0-9 scale: no more than minor problems.
View this bridge on a map → (36.51883, -108.21108)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Culvert | 7 | 7 | Good condition |
Bridge details
| Structure | Continuous concrete culvert |
| Length | about 27 ft |
| Location | 2KM East of Nm Rte 371 |
| NBI structure number | 0000N48796B0822 |
| Condition class | Good |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | April 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 Mexico department of transportation.
Busiest bridges in San Juan County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| Nm-516 over Unnamed Waterway | 1937 | 37,626 | Fair |
| Nm-516 over Unnamed Waterway | 1937 | 29,593 | Fair |
| Nm-516 over Unnamed Waterway | 1937 | 22,275 | Fair |
| Nm-516 over Unnamed Waterway | 1937 | 22,275 | Fair |
| Nm-516 over Unnamed Waterway | 1937 | 22,275 | Fair |
| US-64 Ebl/wbl over Unnamed Waterway | 1964 | 21,685 | Good |
All bridges nearby: San Juan County, NM bridge conditions · every bridge in San Juan County · New Mexico bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.