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Bison Av-n73 on Ra over N73-macarthur Bl Off-rmp

Orange County, California · rated Fair in the 2025 National Bridge Inventory

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

Bison Av-n73 on Ra over N73-macarthur Bl Off-rmp in Orange County, California, is rated in fair condition in the 2025 National Bridge Inventory (as of August 20, 2026).
Its lowest-rated component is the substructure, rated 5 (fair condition) on the 0-9 scale.
It was built in 1996, making it 29 years old at the 2025 inventory.
It carries about 5,820 vehicles a day (traffic count year 2014).
Its listed owner is the state highway agency.
It is one of 479 of the 1,181 inventoried bridges in Orange County rated fair (40.6%); 33 (2.8%) 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 multiple box beam
Length	about 265 ft
Location	12-ora-073-23.60-irvn
NBI structure number	55 0743S
Condition class	Fair

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

Bridge	Built	Vehicles/day	Condition
Interstate 405 over Bolsa Chica Ditch	1959	374,000	Fair
Route 5 over Route 55	1955	329,500	Fair
Interstate 5 over La Paz Rd	1959	327,000	Fair
Interstate 5 over Red Hill Ave	1992	324,300	Fair
State Route 91 over Patt Drain #4	1959	319,000	Good
State Route 91 over Patt Drain #5	1959	319,000	Good