370 Ave over I090

Aurora County, South Dakota · rated Fair in the 2025 National Bridge Inventory

United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled August 20, 2026

• 370 Ave over I090 in Aurora County, South Dakota, is rated in fair condition in the 2025 National Bridge Inventory (as of August 20, 2026).
• Its lowest-rated component is the superstructure, rated 6 (satisfactory condition) on the 0-9 scale.
• It was built in 1965, making it 60 years old at the 2025 inventory.
• It carries about 75 vehicles a day (traffic count year 2023).
• Its listed owner is the state highway agency.
• It is one of 29 of the 61 inventoried bridges in Aurora County rated fair (47.5%); 7 (11.5%) are rated poor.
• Its traffic status in the 2025 inventory is open, no restriction (NBI item 41).
• Its class is unchanged from 2024 (fair), but component ratings moved: substructure 7 to 6, superstructure 5 to 6.
• Its most recent inspection on record is dated November 2024, 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 → (43.73825, -98.79511)

Component ratings

Bridge details

Source: FHWA National Bridge Inventory, 2025 data as reported by the South Dakota department of transportation.

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Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.