US Highway 101 NB over Mad River
FairHumboldt County, California · 01-HUM-101-89.63 · Structure no. 04 0311R
- Built
- 2012
- 13 years old
- Condition
- Fair
- inspected November 2023
- Type
- Box Beam or Girders - Multiple
- Prestressed Concrete Continuous
- Length
- 750 ft
- 4 main spans
- Daily traffic
- 16,500
- 2009 count
- Owner
- State
- State Highway Agency
About this bridge
US Highway 101 NB over Mad River is a prestressed concrete continuous box beam or girders - multiple carrying US Highway 101 NB over Mad River in Humboldt County, California. It was built in 2012, so it is 13 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 16,500 vehicles a day, projected to reach 22,473 by 2041. The structure is 750 ft (228.6 m) long and 51 ft wide. If it were closed, the detour would be 3.7 mi (6 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 | 5 Fair | All primary structural elements are sound but may have minor section loss, cracking, spalling or scour. |
| Superstructure | 7 Good | Some minor problems. |
| Substructure | 7 Good | Some minor problems. |
| Channel and channel protection | 9 Excellent | No problems noted. |
Structure
Traffic and service
Ownership and planned work
Frequently asked questions
When was US Highway 101 NB over Mad River built?
It was built in 2012, making it 13 years old in 2025.
What condition is US Highway 101 NB over Mad River 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 November 2023.
How much traffic does US Highway 101 NB over Mad River carry?
About 16,500 vehicles per day (2009 count).
How long is US Highway 101 NB 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 51 ft wide.
Who owns US Highway 101 NB over Mad River?
It is owned by the State Highway Agency.