STATE ROUTE 55
STATE ROUTE 55 in 12-Ora-055-R6.99-Sa, Orange County, California received a condition grade of B (65/100). Built in 1966, the bridge carries 222K vehicles daily on STATE ROUTE 55 over Macarthur BLVD.
STATE ROUTE 55 carries a B on the BridgeSafety Condition Score with 65/100. 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 1966 and is now 60 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. STATE ROUTE 55 carries an average daily traffic count of 222,000 vehicles, with 12 lane(s) crossing Macarthur BLVD. 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
STATE ROUTE 55 is a 60-year-old bridge located 12-Ora-055-R6.99-Sa in Orange County, California. The bridge carries STATE ROUTE 55 over Macarthur BLVD with 12 traffic lanes, handling approximately 222K vehicles per day. Built in 1966 and reconstructed in 1970, the structure spans 52.4 meters.
The bridge received a Condition Grade of B (65/100) based on Federal Highway Administration inspection data. Its deck is rated 7/9 (good), superstructure 5/9 (fair), and substructure 7/9 (good).
This bridge is owned and maintained by State Highway Agency.
Location Map
Frequently Asked Questions
STATE ROUTE 55 has a Condition Score of 65/100 (Grade B). Its deck is rated 7/9, superstructure 5/9, and substructure 7/9 on the NBI scale. The bridge is not classified as structurally deficient.
STATE ROUTE 55 was built in 1966 and reconstructed in 1970, making it 60 years old. The average bridge age in the United States is 48 years.
STATE ROUTE 55 carries approximately 222K vehicles per day (average daily traffic). The bridge has 12 traffic lanes. It is 52.4 meters long and located on STATE ROUTE 55 in 12-Ora-055-R6.99-Sa, Orange County, California.
No, STATE ROUTE 55 is not classified as structurally deficient. All three primary components (deck, superstructure, and substructure) are rated above 4 on the 0-9 NBI scale.
STATE ROUTE 55 is located 12-Ora-055-R6.99-Sa in Orange County, California. The bridge carries STATE ROUTE 55 over Macarthur BLVD. Its coordinates are 33.698239, -117.861353. It is maintained by State Highway Agency.
STATE ROUTE 55 carries STATE ROUTE 55 over Macarthur BLVD. The bridge is 52.4 meters long and was built in 1966, with reconstruction in 1970.
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.