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SH 121 Ml over Sanderson Gulch

Jefferson County, Colorado · rated Fair in the 2025 National Bridge Inventory

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

SH 121 Ml over Sanderson Gulch in Jefferson County, Colorado, is rated in fair condition in the 2025 National Bridge Inventory (as of August 20, 2026).
Its lowest-rated component is the culvert, rated 5 (fair condition) on the 0-9 scale.
It was built in 1976 and reconstructed in 1986, making it 49 years old at the 2025 inventory.
It carries about 42,000 vehicles a day (traffic count year 2020).
Its listed owner is the state highway agency.
It is one of 279 of the 468 inventoried bridges in Jefferson County rated fair (59.6%); 30 (6.4%) 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

Component	Rating (2025)	FHWA scale meaning
Culvert	5	Fair condition

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

Bridge	Built	Vehicles/day	Condition
I 70 Ml over Garrison Street	1967	118,000	Fair
I 70 Ml over Carr Street	1967	118,000	Fair
I 70 Ml over SH 121 Ml	1996	118,000	Fair
US 6 Ml over SH 95 Ml/sheridan Ave.	2011	114,000	Good
I-70 Ml over SH 72 Ml/ward Road	2024	112,000	Good
I70 Ml over Light Rail	2010	106,000	Fair