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Irr Bia Rte 18 over Colorado River

La Paz County, Arizona · rated Fair in the 2025 National Bridge Inventory

United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled August 20, 2026

Irr Bia Rte 18 over Colorado River in La Paz County, Arizona, is rated in fair condition in the 2025 National Bridge Inventory (as of August 20, 2026).
Its lowest-rated component is the deck, rated 5 (fair condition) on the 0-9 scale.
It was built in 1981, making it 44 years old at the 2025 inventory.
It carries about 274 vehicles a day (traffic count year 2024).
It is one of 104 of the 306 inventoried bridges in La Paz County rated fair (34.0%); 10 (3.3%) are rated poor.
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.

Component ratings


Structure	Continuous prestressed concrete stringer or multi-beam girder
Length	about 560 ft
Location	2.6 Mi W of Bia Rte 1
NBI structure number	00000000000H042
Condition class	Fair

Source: FHWA National Bridge Inventory, 2025 data as reported by the Arizona department of transportation.

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