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Irr Bia Rte 1 over Main Drain

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

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

Irr Bia Rte 1 over Main Drain in La Paz County, Arizona, is rated in poor condition in the 2025 National Bridge Inventory (as of August 20, 2026).
Its lowest-rated component is the substructure, rated 4 (poor condition) on the 0-9 scale.
It was built in 1962, making it 63 years old at the 2025 inventory.
It carries about 3,000 vehicles a day (traffic count year 2021).
It is one of 10 of the 306 inventoried bridges in La Paz County rated poor (3.3%); 10 (3.3%) are rated poor.
A poor rating means at least one major component - deck, superstructure, or substructure - is rated 4 or lower on FHWA's 0-9 scale. It does not by itself mean the bridge is unsafe; bridges judged unsafe are closed or load-restricted by their owners.

Component ratings


Structure	Concrete stringer or multi-beam girder
Length	about 75 ft
Location	0.7 Km N of Bia 1/10 Int.
NBI structure number	00000000000H004
Condition class	Poor

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