U.S. HIGHWAY 101
U.S. HIGHWAY 101 in 04-Mrn-101-12.19-Srf, Marin County, California received a condition grade of C (44/100). Built in 1938, the bridge carries 180K vehicles daily on U.S. HIGHWAY 101 over Lincoln AVE-N101 On Ramp.
U.S. HIGHWAY 101 carries a C on the BridgeSafety Condition Score with 44/100. Component ratings sit in the middle of the FHWA NBI distribution; rehabilitation programming is likely on the owning agency’s medium-term horizon.
The bridge was built in 1938, making it 88 years old — well beyond the typical 50-year design life of bridges constructed in that era. Bridges of this vintage usually need substantial rehabilitation or replacement once their original components have aged out, regardless of current condition ratings. U.S. HIGHWAY 101 carries an average daily traffic count of 180,000 vehicles, with 9 lane(s) crossing Lincoln AVE-N101 On Ramp. 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
U.S. HIGHWAY 101 is a 88-year-old bridge located 04-Mrn-101-12.19-Srf in Marin County, California. The bridge carries U.S. HIGHWAY 101 over Lincoln AVE-N101 On Ramp with 9 traffic lanes, handling approximately 180K vehicles per day. Built in 1938 and reconstructed in 2009, the structure spans 28.2 meters.
The bridge received a Condition Grade of C (44/100) based on Federal Highway Administration inspection data. Its deck is rated 5/9 (fair), superstructure 5/9 (fair), and substructure 7/9 (good).
This bridge is owned and maintained by State Highway Agency.
Location Map
Frequently Asked Questions
U.S. HIGHWAY 101 has a Condition Score of 44/100 (Grade C). Its deck is rated 5/9, superstructure 5/9, and substructure 7/9 on the NBI scale. The bridge is not classified as structurally deficient.
U.S. HIGHWAY 101 was built in 1938 and reconstructed in 2009, making it 88 years old. The average bridge age in the United States is 48 years.
U.S. HIGHWAY 101 carries approximately 180K vehicles per day (average daily traffic). The bridge has 9 traffic lanes. It is 28.2 meters long and located on U.S. HIGHWAY 101 in 04-Mrn-101-12.19-Srf, Marin County, California.
No, U.S. HIGHWAY 101 is not classified as structurally deficient. All three primary components (deck, superstructure, and substructure) are rated above 4 on the 0-9 NBI scale.
U.S. HIGHWAY 101 is located 04-Mrn-101-12.19-Srf in Marin County, California. The bridge carries U.S. HIGHWAY 101 over Lincoln AVE-N101 On Ramp. Its coordinates are 37.988361, -122.526833. It is maintained by State Highway Agency.
U.S. HIGHWAY 101 carries U.S. HIGHWAY 101 over Lincoln AVE-N101 On Ramp. The bridge is 28.2 meters long and was built in 1938, with reconstruction in 2009.
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.