Millbrae Avenue over U.S. Highway 101
FairSan Mateo County, California · 04-SM-101-17.95-MLBR · Structure no. 35 0089
- Built
- 1947
- 78 years old, rebuilt 1976
- Condition
- Fair
- inspected April 2023
- Type
- Stringer/Multi-beam or Girder
- Steel
- Length
- 815 ft
- 14 main spans
- Daily traffic
- 53,747
- 1999 count
- Owner
- State
- State Highway Agency
About this bridge
Millbrae Avenue over U.S. Highway 101 is a steel stringer/multi-beam or girder carrying Millbrae Avenue over U.S. Highway 101 in San Mateo County, California. It was built in 1947 and reconstructed in 1976, so it is 78 years old, older 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 53,747 vehicles a day, roughly 5% of them trucks, projected to reach 74,818 by 2040. The structure is 815 ft (248.5 m) long and 81 ft wide.
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. |
Structure
Traffic and service
Ownership and planned work
Frequently asked questions
When was Millbrae Avenue over U.S. Highway 101 built?
It was built in 1947, making it 78 years old in 2025. It was reconstructed in 1976.
What condition is Millbrae 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 April 2023.
How much traffic does Millbrae Avenue over U.S. Highway 101 carry?
About 53,747 vehicles per day (1999 count), of which roughly 5% are trucks.
How long is Millbrae Avenue over U.S. Highway 101?
The structure is 815 ft (248.5 m) long with a longest span of 75 ft (23 m) and a deck 81 ft wide.
Who owns Millbrae Avenue over U.S. Highway 101?
It is owned by the State Highway Agency.