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Interstate 680 NB over Mt Diablo Boulevard

Contra Costa County, California · rated Fair in the 2025 National Bridge Inventory

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

Interstate 680 NB over Mt Diablo Boulevard in Contra Costa County, California, is rated in fair condition in the 2025 National Bridge Inventory (as of August 20, 2026).
Its lowest-rated component is the deck, rated 5 (fair condition) on the 0-9 scale.
It was built in 1998, making it 27 years old at the 2025 inventory.
It carries about 87,700 vehicles a day (traffic count year 2017).
Its listed owner is the state highway agency.
It is one of 306 of the 622 inventoried bridges in Contra Costa County rated fair (49.2%); 56 (9.0%) 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.

Component ratings


Structure	Continuous prestressed concrete multiple box beam
Length	about 202 ft
Location	04-cc-680-14.22-wlc
NBI structure number	28 0128R
Condition class	Fair

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

Bridge	Built	Vehicles/day	Condition
Interstate 680 over Canal & Bike Path	1956	257,000	Fair
Interstate 680 over Monument Boulevard	1998	235,000	Poor
Interstate 680 over Parkside Drive	1960	235,000	Good
Interstate 680 over Rudgear Road	1964	197,400	Good
Interstate 680 over Livorna Road	1964	197,400	Good
Interstate 680 over Newell Avenue	1994	195,300	Fair