I-75 SB
I-75 SB in 0.3 MI N Of Gibsonton DR, Hillsborough County, Florida received a condition grade of B (70/100). Built in 1981, the bridge carries 157K vehicles daily on I-75 SB over Alafia River.
I-75 SB carries a B on the BridgeSafety Condition Score with 70/100. Most component ratings are solid; one or two may show wear consistent with the structure’s age, but the bridge is not flagged as structurally deficient.
The bridge was built in 1981, making it 45 years old — past the early-life period but still well within typical service life. Routine inspections and modest repair work are normal for bridges in this age band. I-75 SB carries an average daily traffic count of 157,000 vehicles, with 4 lane(s) crossing Alafia River. 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-75 SB is a 45-year-old bridge located 0.3 MI N Of Gibsonton DR in Hillsborough County, Florida. The bridge carries I-75 SB over Alafia River with 4 traffic lanes, handling approximately 157K vehicles per day. Built in 1981, the structure spans 474 meters.
The bridge received a Condition Grade of B (70/100) based on Federal Highway Administration inspection data. Its deck is rated 5/9 (fair), superstructure 7/9 (good), and substructure 7/9 (good).
This bridge is owned and maintained by State Highway Agency.
Location Map
Frequently Asked Questions
I-75 SB has a Condition Score of 70/100 (Grade B). Its deck is rated 5/9, superstructure 7/9, and substructure 7/9 on the NBI scale. The bridge is not classified as structurally deficient.
I-75 SB was built in 1981, making it 45 years old. The average bridge age in the United States is 48 years.
I-75 SB carries approximately 157K vehicles per day (average daily traffic). The bridge has 4 traffic lanes. It is 474 meters long and located on I-75 SB in 0.3 MI N Of Gibsonton DR, Hillsborough County, Florida.
No, I-75 SB is not classified as structurally deficient. All three primary components (deck, superstructure, and substructure) are rated above 4 on the 0-9 NBI scale.
I-75 SB is located 0.3 MI N Of Gibsonton DR in Hillsborough County, Florida. The bridge carries I-75 SB over Alafia River. Its coordinates are 27.857361, -82.347000. It is maintained by State Highway Agency.
I-75 SB carries I-75 SB over Alafia River. The bridge is 474 meters long and was built in 1981.
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.