I 93 SB
I 93 SB in Unit 1, Suffolk County, Massachusetts received a condition grade of B (67/100). Built in 2000, the bridge carries 165K vehicles daily on I 93 SB over HWY W Fourth ST.
I 93 SB carries a B on the BridgeSafety Condition Score with 67/100. 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 2000, making it 26 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 93 SB carries an average daily traffic count of 164,570 vehicles, with 6 lane(s) crossing HWY W Fourth ST. 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 93 SB is a 26-year-old bridge located Unit 1 in Suffolk County, Massachusetts. The bridge carries I 93 SB over HWY W Fourth ST with 6 traffic lanes, handling approximately 165K vehicles per day. Built in 2000, the structure spans 91.3 meters.
The bridge received a Condition Grade of B (67/100) based on Federal Highway Administration inspection data. Its deck is rated 6/9 (fair), superstructure 6/9 (fair), and substructure 6/9 (fair).
This bridge is owned and maintained by State Highway Agency.
Location Map
Frequently Asked Questions
I 93 SB has a Condition Score of 67/100 (Grade B). Its deck is rated 6/9, superstructure 6/9, and substructure 6/9 on the NBI scale. The bridge is not classified as structurally deficient.
I 93 SB was built in 2000, making it 26 years old. The average bridge age in the United States is 48 years.
I 93 SB carries approximately 165K vehicles per day (average daily traffic). The bridge has 6 traffic lanes. It is 91.3 meters long and located on I 93 SB in Unit 1, Suffolk County, Massachusetts.
No, I 93 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 93 SB is located Unit 1 in Suffolk County, Massachusetts. The bridge carries I 93 SB over HWY W Fourth ST. Its coordinates are 42.342947, -71.062272. It is maintained by State Highway Agency.
I 93 SB carries I 93 SB over HWY W Fourth ST. The bridge is 91.3 meters long and was built in 2000.
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.