Atherton Avenue over U.S. Highway 101
FairMarin County, California · 04-MRN-101-R22.00-NVTO · Structure no. 27 0093
- Built
- 1974
- 51 years old
- Condition
- Fair
- inspected June 2023
- Type
- Box Beam or Girders - Multiple
- Prestressed Concrete Continuous
- Length
- 234 ft
- 2 main spans
- Daily traffic
- 8,760
- 2001 count
- Owner
- State
- State Highway Agency
About this bridge
Atherton Avenue over U.S. Highway 101 is a prestressed concrete continuous box beam or girders - multiple carrying Atherton Avenue over U.S. Highway 101 in Marin County, California. It was built in 1974, so it is 51 years old, younger than the California average of 54.8 years.
The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 5 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.
It carries about 8,760 vehicles a day, roughly 1% of them trucks, projected to reach 11,448 by 2041. The structure is 234 ft (71.3 m) long and 94 ft wide. If it were closed, the detour would be 1.9 mi (3 km).
Location
Open in Google MapsCondition and inspection
The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.
| Component | Rating | Meaning |
|---|---|---|
| Deck | 7 Good | Some minor problems. |
| Superstructure | 5 Fair | All primary structural elements are sound but may have minor section loss, cracking, spalling or scour. |
| Substructure | 7 Good | Some minor problems. |
Structure
Traffic and service
Ownership and planned work
Frequently asked questions
When was Atherton Avenue over U.S. Highway 101 built?
It was built in 1974, making it 51 years old in 2025.
What condition is Atherton Avenue over U.S. Highway 101 in?
The National Bridge Inventory rates it in fair condition. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. The last reported inspection was in June 2023.
How much traffic does Atherton Avenue over U.S. Highway 101 carry?
About 8,760 vehicles per day (2001 count), of which roughly 1% are trucks.
How long is Atherton Avenue over U.S. Highway 101?
The structure is 234 ft (71.3 m) long with a longest span of 116 ft (35.4 m) and a deck 94 ft wide.
Who owns Atherton Avenue over U.S. Highway 101?
It is owned by the State Highway Agency.