Hwy South Rotary over St 99 Sullivan Sq Undrps

Suffolk County, Massachusetts · rated Fair in the 2025 National Bridge Inventory

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

• Hwy South Rotary over St 99 Sullivan Sq Undrps in Suffolk County, Massachusetts, is rated in fair condition in the 2025 National Bridge Inventory (as of August 20, 2026).
• Its lowest-rated component is the deck, rated 6 (satisfactory condition) on the 0-9 scale.
• It was built in 1951, making it 74 years old at the 2025 inventory.
• It carries about 27,025 vehicles a day (traffic count year 2024).
• Its listed owner is a city or municipal highway agency.
• It is one of 331 of the 490 inventoried bridges in Suffolk County rated fair (67.6%); 49 (10.0%) are rated poor.
• 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 → (42.38387, -71.07343)

Component ratings

Bridge details

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

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