INTERSTATE 405
INTERSTATE 405 in 07-La-405-32.72-La, Los Angeles County, California received a condition grade of B (77/100). Built in 1975, the bridge carries 269K vehicles daily on INTERSTATE 405 over Hillside.
INTERSTATE 405 carries a B on the BridgeSafety Condition Score with 77/100. Most component ratings are solid; one or two may show wear consistent with the structure’s age, but the bridge is not flagged as structurally deficient.
The bridge was built in 1975 and is now 51 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 268,700 vehicles, with 12 lane(s) crossing Hillside. 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 51-year-old bridge located 07-La-405-32.72-La in Los Angeles County, California. The bridge carries INTERSTATE 405 over Hillside with 12 traffic lanes, handling approximately 269K vehicles per day. Built in 1975, the structure spans 141.7 meters.
The bridge received a Condition Grade of B (77/100) based on Federal Highway Administration inspection data. Its deck is rated 7/9 (good), superstructure 7/9 (good), and substructure 7/9 (good).
This bridge is owned and maintained by State Highway Agency.
Location Map
Frequently Asked Questions
INTERSTATE 405 has a Condition Score of 77/100 (Grade B). Its deck is rated 7/9, superstructure 7/9, and substructure 7/9 on the NBI scale. The bridge is not classified as structurally deficient.
INTERSTATE 405 was built in 1975, making it 51 years old. The average bridge age in the United States is 48 years.
INTERSTATE 405 carries approximately 269K vehicles per day (average daily traffic). The bridge has 12 traffic lanes. It is 141.7 meters long and located on INTERSTATE 405 in 07-La-405-32.72-La, Los Angeles County, California.
No, INTERSTATE 405 is not classified as structurally deficient. All three primary components (deck, superstructure, and substructure) are rated above 4 on the 0-9 NBI scale.
INTERSTATE 405 is located 07-La-405-32.72-La in Los Angeles County, California. The bridge carries INTERSTATE 405 over Hillside. Its coordinates are 34.070406, -118.464917. It is maintained by State Highway Agency.
INTERSTATE 405 carries INTERSTATE 405 over Hillside. The bridge is 141.7 meters long and was built in 1975.
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.