Highland Lake Rd over Mokelumne River
Alpine County, California · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- Highland Lake Rd over Mokelumne River in Alpine County, California, is rated in fair condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the substructure, rated 5 (fair condition) on the 0-9 scale.
- It was built in 1989, making it 36 years old at the 2025 inventory.
- It carries about 25 vehicles a day (traffic count year 1990).
- Its listed owner is the county highway agency.
- It is one of 21 of the 33 inventoried bridges in Alpine County rated fair (63.6%); 2 (6.1%) are rated poor.
- Its traffic status in the 2025 inventory is open, no restriction (NBI item 41).
- Its condition class and component ratings are unchanged from the 2024 inventory.
- Its most recent inspection on record is dated September 2023, on a 24-month routine inspection cycle.
- A fair rating means the lowest-rated major component scores 5 or 6 on FHWA's 0-9 scale: some deterioration or minor section loss, but the structure is sound. It is the middle class, not a warning.
View this bridge on a map → (38.5142, -119.80235)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Superstructure | 7 | 7 | Good condition |
| Substructure | 5 | 5 | Fair condition |
Bridge details
| Structure | Steel deck arch |
| Length | about 22 ft |
| Location | 3.3 Mi S of S.H. 4 |
| NBI structure number | 31C0019 |
| Condition class | Fair |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | September 2023 |
| Inspection interval (item 91) | 24 months |
| Scour (item 113) | 5: foundations stable, scour within the limits of the footing or piles |
Source: FHWA National Bridge Inventory, 2025 data as reported by the California department of transportation.
Busiest bridges in Alpine County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| State Route 88 over West Fork Carson River | 1952 | 3,225 | Fair |
| Old State Route 88 over West Fork Carson River | 1939 | 3,200 | Fair |
| State Route 89 over West Fork Carson River | 1960 | 3,200 | Fair |
| State Route 88 over West Fork Carson River | 1963 | 3,200 | Good |
| State Route 88 over West Fork Carson River | 1963 | 3,200 | Good |
| State Route 89 over Wildlife Access | 1980 | 3,050 | Good |
All bridges nearby: Alpine County, CA bridge conditions · every bridge in Alpine County · California bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.