County Line Road over Spring Gulch #2
Boulder County, Colorado · rated Good in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- County Line Road over Spring Gulch #2 in Boulder County, Colorado, is rated in good condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the culvert, rated 7 (good condition) on the 0-9 scale.
- It was built in 2021, making it 4 years old at the 2025 inventory.
- It carries about 15,509 vehicles a day (traffic count year 2023).
- Its listed owner is a city or municipal highway agency.
- It is one of 103 of the 321 inventoried bridges in Boulder County rated good (32.1%); 7 (2.2%) are rated poor.
- 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 → (40.17722, -105.0554)
Component ratings
| Component | Rating (2025) | FHWA scale meaning |
|---|---|---|
| Culvert | 7 | Good condition |
Bridge details
| Structure | Concrete culvert |
| Length | about 33 ft |
| Location | 0.20 Mi N. of E 9TH Ave |
| NBI structure number | LONG-CLR-E9TH |
| Condition class | Good |
Source: FHWA National Bridge Inventory, 2025 data as reported by the Colorado department of transportation.
Busiest bridges in Boulder County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| US 36 Ml over South Boulder Creek | 1951 | 77,000 | Good |
| US 36 Ml over Davidson Ditch | 2015 | 77,000 | Good |
| US 36 Ml over Coal Creek | 2015 | 66,000 | Good |
| US 36 Ml over Canyon Creek | 1951 | 45,000 | Fair |
| Table Mesa Drive over US 36 Ml | 1951 | 44,000 | Fair |
| SH 157 Ramp over US 36 Ml | 1971 | 44,000 | Fair |
All bridges nearby: Boulder County, CO bridge conditions · every bridge in Boulder County · Colorado bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.