State Route 84 over San Gregorio Creek
San Mateo County, California · rated Good in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- State Route 84 over San Gregorio Creek in San Mateo County, California, is rated in good condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the deck, rated 7 (good condition) on the 0-9 scale.
- It was built in 1957, making it 68 years old at the 2025 inventory.
- It carries about 1,400 vehicles a day (traffic count year 2009).
- Its listed owner is the state highway agency.
- It is one of 100 of the 361 inventoried bridges in San Mateo County rated good (27.7%); 37 (10.2%) 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 May 2024, on a 24-month routine inspection cycle.
- It is coded scour critical (NBI item 113 = 3): scour critical: foundations unstable for the assessed or calculated scour.
- A good rating means every major component - deck, superstructure, substructure, or culvert - is rated 7 or higher on FHWA's 0-9 scale: no more than minor problems.
View this bridge on a map → (37.31356, -122.28423)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 7 | 7 | Good condition |
| Superstructure | 7 | 7 | Good condition |
| Substructure | 7 | 7 | Good condition |
Bridge details
| Structure | Continuous concrete tee beam |
| Length | about 102 ft |
| Location | 04-sm-084-7.55 |
| NBI structure number | 35 0166 |
| Condition class | Good |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | May 2024 |
| Inspection interval (item 91) | 24 months |
| Scour (item 113) | 3: scour critical: foundations unstable for the assessed or calculated scour |
Source: FHWA National Bridge Inventory, 2025 data as reported by the California department of transportation.
Busiest bridges in San Mateo County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| U.S. Highway 101 over San Mateo Creek | 1928 | 236,000 | Good |
| US 101 Rollins Rd over Transmission Canal | 1928 | 232,000 | Fair |
| US 101 Mcdonnell over Millbrae Slough | 1947 | 226,000 | Fair |
| US 101 W&e Bayshr over San Francisquito Creek | 2018 | 225,800 | Good |
| Holly Street over US Highway 101 | 1954 | 201,000 | Fair |
| Whipple Avenue over US Highway 101 | 1958 | 201,000 | Good |
All bridges nearby: San Mateo County, CA bridge conditions · every bridge in San Mateo County · California bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.