Irr Bia Route 1 over Tyson Waterway
La Paz County, Arizona · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- Irr Bia Route 1 over Tyson Waterway in La Paz County, Arizona, 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 1958, making it 67 years old at the 2025 inventory.
- It carries about 1,700 vehicles a day (traffic count year 2019).
- It is one of 104 of the 306 inventoried bridges in La Paz County rated fair (34.0%); 10 (3.3%) are rated poor.
- Its traffic status in the 2025 inventory is posted for load (NBI item 41).
- Its condition class and component ratings are unchanged from the 2024 inventory.
- Its most recent inspection on record is dated April 2019, 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 → (33.75161, -114.4686)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 6 | 6 | Satisfactory condition |
| Superstructure | 6 | 6 | Satisfactory condition |
| Substructure | 7 | 7 | Good condition |
Bridge details
| Structure | Continuous concrete slab |
| Length | about 93 ft |
| Location | 1.6 Km S of Bia 1/56 Int. |
| NBI structure number | 00000000000H008 |
| Condition class | Fair |
| Traffic status (item 41) | Posted for load |
| Last inspection (item 90) | April 2019 |
| 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 Arizona department of transportation.
Busiest bridges in La Paz County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| I 10 EB and WB over Colorado River | 1960 | 60,000 | Good |
| SR 95 over Silver Creek | 1978 | 32,600 | Fair |
| I 10; EB & WB over Wash | 1949 | 27,198 | Good |
| I 10; EB & WB over Wash | 1949 | 27,198 | Fair |
| I 10; EB & WB over Italian Wash | 1953 | 25,941 | Good |
| I 10; WB over Wash | 1969 | 25,941 | Good |
All bridges nearby: La Paz County, AZ bridge conditions · every bridge in La Paz County · Arizona bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.