US Highway 101 SB over Mad River
GoodHumboldt County, California · 01-HUM-101-89.63 · Structure no. 04 0311L
- Built
- 2011
- 14 years old
- Condition
- Good
- inspected November 2023
- Type
- Box Beam or Girders - Multiple
- Prestressed Concrete Continuous
- Length
- 750 ft
- 4 main spans
- Daily traffic
- 18,500
- 2010 count
- Owner
- State
- State Highway Agency
About this bridge
US Highway 101 SB over Mad River is a prestressed concrete continuous box beam or girders - multiple carrying US Highway 101 SB over Mad River in Humboldt County, California. It was built in 2011, so it is 14 years old, younger than the California average of 54.8 years.
The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 7 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.
It carries about 18,500 vehicles a day, roughly 12% of them trucks, projected to reach 21,998 by 2043. The structure is 750 ft (228.6 m) long and 39 ft wide. If it were closed, the detour would be 3.1 mi (5 km).
Location
Open in Google MapsCondition and inspection
All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.
| Component | Rating | Meaning |
|---|---|---|
| Deck | 7 Good | Some minor problems. |
| Superstructure | 7 Good | Some minor problems. |
| Substructure | 7 Good | Some minor problems. |
| Channel and channel protection | 7 Good | Some minor problems. |
Structure
Traffic and service
Ownership and planned work
Frequently asked questions
When was US Highway 101 SB over Mad River built?
It was built in 2011, making it 14 years old in 2025.
What condition is US Highway 101 SB over Mad River in?
The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in November 2023.
How much traffic does US Highway 101 SB over Mad River carry?
About 18,500 vehicles per day (2010 count), of which roughly 12% are trucks.
How long is US Highway 101 SB over Mad River?
The structure is 750 ft (228.6 m) long with a longest span of 225 ft (68.6 m) and a deck 39 ft wide.
Who owns US Highway 101 SB over Mad River?
It is owned by the State Highway Agency.