170 Rd. over South Cottonwood River
Marion County, Kansas · rated Poor in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- 170 Rd. over South Cottonwood River in Marion County, Kansas, is rated in poor condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the culvert, rated 3 (serious condition) on the 0-9 scale.
- It was built in 1920, making it 105 years old at the 2025 inventory.
- It carries about 20 vehicles a day (traffic count year 2020).
- Its listed owner is the county highway agency.
- It is one of 35 of the 323 inventoried bridges in Marion County rated poor (10.8%); 35 (10.8%) are rated poor.
- Its traffic status in the 2025 inventory is posted for load (NBI item 41).
- Its condition class and component ratings are unchanged from the 2024 inventory.
- Its most recent inspection on record is dated December 2024, on a 12-month routine inspection cycle.
- It is coded scour critical (NBI item 113 = 3): scour critical: foundations unstable for the assessed or calculated scour.
- A poor rating means at least one major component - deck, superstructure, or substructure - is rated 4 or lower on FHWA's 0-9 scale. It does not by itself mean the bridge is unsafe; bridges judged unsafe are closed or load-restricted by their owners.
View this bridge on a map → (38.31881, -97.28092)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Culvert | 3 | 3 | Serious condition |
Bridge details
| Structure | Concrete culvert |
| Length | about 30 ft |
| Location | 1.5S 4.1W of Hillsboro |
| NBI structure number | 000570825905320 |
| Condition class | Poor |
| Traffic status (item 41) | Posted for load |
| Last inspection (item 90) | December 2024 |
| Inspection interval (item 91) | 12 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 Kansas department of transportation.
Busiest bridges in Marion County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| US-50 Hwy over Spring Creek | 1994 | 5,402 | Good |
| US-50 Hwy over Doyle Creek Drainage | 1994 | 5,097 | Good |
| US-50 Hwy over Doyle Creek Drainage | 1998 | 5,097 | Good |
| US-50 Hwy over Doyle Creek Drainage | 1998 | 5,097 | Good |
| US-50 Hwy over Doyle Creek Drainage | 1998 | 5,097 | Good |
| US-50 Hwy over Union Pacific RR. | 1994 | 4,812 | Good |
All bridges nearby: Marion County, KS bridge conditions · every bridge in Marion County · Kansas bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.