Duncan Road over Mormon Slough
GoodSan Joaquin County, California · 0.6 MI N Copperopolis RD · Structure no. 29C0111
- Built
- 1973
- 52 years old
- Condition
- Good
- inspected March 2023
- Type
- Tee Beam
- Concrete Continuous
- Length
- 173 ft
- 3 main spans
- Daily traffic
- 1,839
- 2007 count
- Owner
- County
- County Highway Agency
About this bridge
Duncan Road over Mormon Slough is a concrete continuous tee beam carrying Duncan Road over Mormon Slough in San Joaquin County, California. It was built in 1973, so it is 52 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 1,839 vehicles a day, roughly 5% of them trucks, projected to reach 2,142 by 2041. The structure is 173 ft (52.8 m) long and 32 ft wide. If it were closed, the detour would be 6.2 mi (10 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 | 6 Satisfactory | Structural elements show some minor deterioration. |
Structure
Traffic and service
Ownership and planned work
Frequently asked questions
When was Duncan Road over Mormon Slough built?
It was built in 1973, making it 52 years old in 2025.
What condition is Duncan Road over Mormon Slough 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 March 2023.
How much traffic does Duncan Road over Mormon Slough carry?
About 1,839 vehicles per day (2007 count), of which roughly 5% are trucks.
How long is Duncan Road over Mormon Slough?
The structure is 173 ft (52.8 m) long with a longest span of 68 ft (20.8 m) and a deck 32 ft wide.
Who owns Duncan Road over Mormon Slough?
It is owned by the County Highway Agency.