I-15 (SR-15)
I-15 (SR-15) in Approx. 3000 So. On I-15, Salt Lake County, Utah received a condition grade of F (0/100). Built in 1959, the bridge carries 237K vehicles daily on I-15 (SR-15) over Mill Creek. It is classified as structurally deficient.
I-15 (SR-15) carries an F on the BridgeSafety Condition Score with 0/100 — the bottom tier of the FHWA NBI distribution. Component ratings flag the structure for near-term rehabilitation or replacement; the bridge may remain open to traffic but is on the priority list for action.
The bridge was built in 1959 and is now 67 years old, at or past the typical 50-year design life for bridges of its vintage. Maintenance and inspection cycles are correspondingly more involved than for newer structures. I-15 (SR-15) carries an average daily traffic count of 236,900 vehicles, with 13 lane(s) crossing Mill Creek. The owning agency is State Highway Agency; bridge inspection records flow into the federal NBI database annually.
Component Ratings
The riding surface, evaluated for cracking, spalling, and wear
Beams, girders, and trusses that support the deck
Piers, abutments, and foundations below the deck
Bridge Details
About This Bridge
I-15 (SR-15) is a 67-year-old bridge located Approx. 3000 So. On I-15 in Salt Lake County, Utah. The bridge carries I-15 (SR-15) over Mill Creek with 13 traffic lanes, handling approximately 237K vehicles per day. Built in 1959, the structure spans 9 meters.
The bridge received a Condition Grade of F (0/100) based on Federal Highway Administration inspection data. Its deck is rated 0/9 (serious), superstructure 0/9 (serious), and substructure 0/9 (serious). The bridge is classified as structurally deficient, meaning at least one major component is rated 4 or below, this signals a need for repair or replacement but does not necessarily indicate an immediate safety hazard.
This bridge is owned and maintained by State Highway Agency.
Location Map
Frequently Asked Questions
I-15 (SR-15) has a Condition Score of 0/100 (Grade F). Its deck is rated 0/9, superstructure 0/9, and substructure 0/9 on the NBI scale. The bridge is classified as structurally deficient.
I-15 (SR-15) was built in 1959, making it 67 years old. The average bridge age in the United States is 48 years.
I-15 (SR-15) carries approximately 237K vehicles per day (average daily traffic). The bridge has 13 traffic lanes. It is 9 meters long and located on I-15 (SR-15) in Approx. 3000 So. On I-15, Salt Lake County, Utah.
Yes, I-15 (SR-15) is classified as structurally deficient because at least one of its primary components (deck, superstructure, or substructure) is rated 4 or below on the 0-9 NBI scale. This does not necessarily mean it is unsafe, but it requires significant repair or replacement.
I-15 (SR-15) is located Approx. 3000 So. On I-15 in Salt Lake County, Utah. The bridge carries I-15 (SR-15) over Mill Creek. Its coordinates are 40.706250, -111.903611. It is maintained by State Highway Agency.
I-15 (SR-15) carries I-15 (SR-15) over Mill Creek. The bridge is 9 meters long and was built in 1959.
Condition Score is calculated from deck (33%), superstructure (33%), and substructure (34%) NBI ratings with an age penalty for bridges over 50 years.
Source: FHWA National Bridge Inventory, 2026.