STATE ROUTE 99
STATE ROUTE 99 in 06-Ker-099-25.35-Bkd, Kern County, California received a condition grade of B (63/100). Built in 1961, the bridge carries 140K vehicles daily on STATE ROUTE 99 over Kern River.
STATE ROUTE 99 carries a B on the BridgeSafety Condition Score with 63/100. 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 1961 and is now 65 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 99 carries an average daily traffic count of 140,000 vehicles, with 10 lane(s) crossing Kern River. 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 99 is a 65-year-old bridge located 06-Ker-099-25.35-Bkd in Kern County, California. The bridge carries STATE ROUTE 99 over Kern River with 10 traffic lanes, handling approximately 140K vehicles per day. Built in 1961 and reconstructed in 1996, the structure spans 136.4 meters.
The bridge received a Condition Grade of B (63/100) based on Federal Highway Administration inspection data. Its deck is rated 7/9 (good), superstructure 7/9 (good), and substructure 5/9 (fair).
This bridge is owned and maintained by State Highway Agency.
Location Map
Frequently Asked Questions
STATE ROUTE 99 has a Condition Score of 63/100 (Grade B). Its deck is rated 7/9, superstructure 7/9, and substructure 5/9 on the NBI scale. The bridge is not classified as structurally deficient.
STATE ROUTE 99 was built in 1961 and reconstructed in 1996, making it 65 years old. The average bridge age in the United States is 48 years.
STATE ROUTE 99 carries approximately 140K vehicles per day (average daily traffic). The bridge has 10 traffic lanes. It is 136.4 meters long and located on STATE ROUTE 99 in 06-Ker-099-25.35-Bkd, Kern County, California.
No, STATE ROUTE 99 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 99 is located 06-Ker-099-25.35-Bkd in Kern County, California. The bridge carries STATE ROUTE 99 over Kern River. Its coordinates are 35.378922, -119.044161. It is maintained by State Highway Agency.
STATE ROUTE 99 carries STATE ROUTE 99 over Kern River. The bridge is 136.4 meters long and was built in 1961, with reconstruction in 1996.
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.