US 20 Wbl over Thorton Ic
Madison County, Idaho · rated Good in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- US 20 Wbl over Thorton Ic in Madison County, Idaho, 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 2016, making it 9 years old at the 2025 inventory.
- It carries about 15,250 vehicles a day (traffic count year 2023).
- Its listed owner is the state highway agency.
- It is one of 26 of the 80 inventoried bridges in Madison County rated good (32.5%); 0 (0.0%) 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 February 2023, on a 48-month routine inspection cycle.
- 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 → (43.76228, -111.84458)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 7 | 7 | Good condition |
| Superstructure | 8 | 8 | Very good condition |
| Substructure | 8 | 8 | Very good condition |
Bridge details
| Structure | Prestressed concrete stringer or multi-beam girder |
| Length | about 98 ft |
| Location | at Thorton |
| NBI structure number | 000000000034695 |
| Condition class | Good |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | February 2023 |
| Inspection interval (item 91) | 48 months |
| Scour (item 113) | N: not over a waterway |
Source: FHWA National Bridge Inventory, 2025 data as reported by the Idaho department of transportation.
Busiest bridges in Madison County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| SH 33 over Rexburg Canal | 1938 | 20,000 | Fair |
| SH 33 over S.fk.teton River | 1971 | 17,000 | Fair |
| US 20 Ebl over Stp 7726;S.REXBURG Ic | 1981 | 15,750 | Good |
| US 20 Wbl over Stp 7726;S.REXBURG Ic | 1981 | 15,750 | Good |
| US 20 Ebl over Texas Slough | 1981 | 15,250 | Good |
| US 20 Wbl over Texas Slough | 1981 | 15,250 | Good |
All bridges nearby: Madison County, ID bridge conditions · every bridge in Madison County · Idaho bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.