INTERSTATE 405
INTERSTATE 405 in 12-Ora-405-24.10-Slb, Orange County, California received a condition grade of F (0/100). Built in 1965, the bridge carries 255K vehicles daily on INTERSTATE 405 over Los Alamitos Channel. It is classified as structurally deficient.
INTERSTATE 405 carries an F on the BridgeSafety Condition Score with 0/100 — the bottom tier of the FHWA NBI distribution. Component ratings flag the structure for near-term rehabilitation or replacement; the bridge may remain open to traffic but is on the priority list for action.
The bridge was built in 1965 and is now 61 years old, at or past the typical 50-year design life for bridges of its vintage. Maintenance and inspection cycles are correspondingly more involved than for newer structures. INTERSTATE 405 carries an average daily traffic count of 255,000 vehicles, with 10 lane(s) crossing Los Alamitos Channel. The owning agency is State Highway Agency; bridge inspection records flow into the federal NBI database annually.
Component Ratings
The riding surface, evaluated for cracking, spalling, and wear
Beams, girders, and trusses that support the deck
Piers, abutments, and foundations below the deck
Bridge Details
About This Bridge
INTERSTATE 405 is a 61-year-old bridge located 12-Ora-405-24.10-Slb in Orange County, California. The bridge carries INTERSTATE 405 over Los Alamitos Channel with 10 traffic lanes, handling approximately 255K vehicles per day. Built in 1965, the structure spans 11 meters.
The bridge received a Condition Grade of F (0/100) based on Federal Highway Administration inspection data. Its deck is rated 0/9 (serious), superstructure 0/9 (serious), and substructure 0/9 (serious). The bridge is classified as structurally deficient, meaning at least one major component is rated 4 or below, this signals a need for repair or replacement but does not necessarily indicate an immediate safety hazard.
This bridge is owned and maintained by State Highway Agency.
Location Map
Frequently Asked Questions
INTERSTATE 405 has a Condition Score of 0/100 (Grade F). Its deck is rated 0/9, superstructure 0/9, and substructure 0/9 on the NBI scale. The bridge is classified as structurally deficient.
INTERSTATE 405 was built in 1965, making it 61 years old. The average bridge age in the United States is 48 years.
INTERSTATE 405 carries approximately 255K vehicles per day (average daily traffic). The bridge has 10 traffic lanes. It is 11 meters long and located on INTERSTATE 405 in 12-Ora-405-24.10-Slb, Orange County, California.
Yes, INTERSTATE 405 is classified as structurally deficient because at least one of its primary components (deck, superstructure, or substructure) is rated 4 or below on the 0-9 NBI scale. This does not necessarily mean it is unsafe, but it requires significant repair or replacement.
INTERSTATE 405 is located 12-Ora-405-24.10-Slb in Orange County, California. The bridge carries INTERSTATE 405 over Los Alamitos Channel. Its coordinates are 33.785497, -118.092422. It is maintained by State Highway Agency.
INTERSTATE 405 carries INTERSTATE 405 over Los Alamitos Channel. The bridge is 11 meters long and was built in 1965.
Condition Score is calculated from deck (33%), superstructure (33%), and substructure (34%) NBI ratings with an age penalty for bridges over 50 years.
Source: FHWA National Bridge Inventory, 2026.