U.S. Highway 101 over Westside RD
PoorSonoma County, California · 04-SON-101-34.88 · Structure no. 20 0147
- Built
- 1960
- 65 years old
- Condition
- Poor
- inspected April 2023
- Type
- Box Beam or Girders - Multiple
- Concrete Continuous
- Length
- 182 ft
- 3 main spans
- Daily traffic
- 45,500
- 2017 count
- Owner
- State
- State Highway Agency
About this bridge
U.S. Highway 101 over Westside RD is a concrete continuous box beam or girders - multiple carrying U.S. Highway 101 over Westside RD in Sonoma County, California. It was built in 1960, so it is 65 years old, older than the California average of 54.8 years.
The most recent inspection reported to the Federal Highway Administration rates it in poor condition with a lowest component rating of 4 out of 9. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.
It carries about 45,500 vehicles a day, roughly 13% of them trucks, projected to reach 88,047 by 2045. The structure is 182 ft (55.5 m) long and 91 ft wide. If it were closed, the detour would be 19.9 mi (32 km).
Location
Open in Google MapsCondition and inspection
The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.
| Component | Rating | Meaning |
|---|---|---|
| Deck | 4 Poor | Advanced section loss, deterioration, spalling or scour. |
| Superstructure | 7 Good | Some minor problems. |
| Substructure | 7 Good | Some minor problems. |
Structure
Traffic and service
Ownership and planned work
Frequently asked questions
When was U.S. Highway 101 over Westside RD built?
It was built in 1960, making it 65 years old in 2025.
What condition is U.S. Highway 101 over Westside RD in?
The National Bridge Inventory rates it in poor condition. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions. The last reported inspection was in April 2023.
How much traffic does U.S. Highway 101 over Westside RD carry?
About 45,500 vehicles per day (2017 count), of which roughly 13% are trucks.
How long is U.S. Highway 101 over Westside RD?
The structure is 182 ft (55.5 m) long with a longest span of 92 ft (28 m) and a deck 91 ft wide.
Who owns U.S. Highway 101 over Westside RD?
It is owned by the State Highway Agency.