Structure N120414U3MBTNBI · Middlesex County, MA
Carries HWY Beacon ST over Tr Green Line D, Over Green Line.
37 ft end to end. Lengths and the car on the deck are drawn to the same scale. Each part is colored by its latest inspection rating. The inventory records lengths but not heights or the layout of the shorter spans, so those are drawn as typical for a box-beam bridge.
| State | Massachusetts |
| County | Middlesex |
| Location | Over Green Line |
| Carries | HWY Beacon ST |
| Crosses | Tr Green Line D |
| Coordinates | 42.32624, -71.23123 |
| Material | Prestressed Concrete |
| Design | Box Beam - Multiple |
| Total Length | 37.1 ft (11.3 m) |
| Max Span | 35.8 ft (10.9 m) |
| Deck Width | 52.2 ft (15.9 m) |
| Deck Area | 179.7 sq m |
| Main Spans | 1 |
| Year Built | 1917 (reconstructed 1997) |
| Avg Daily Traffic | 24,000 (2022) |
| Truck Traffic | 3% |
| Lanes On Bridge | 2 |
| Last Inspection | October 2022 |
| Inspection Frequency | Every 24 months |
| Owner | Other State Agencies |
| Historical Significance | Bridge is possibly eligible (requires evaluation) |
| Scour Critical | Not applicable |
| Structure Number | N120414U3MBTNBI |
Inspectors rate each major part of a bridge (the deck you drive on, the superstructure of beams that holds it up, and the substructure of piers and abutments beneath) on a 0–9 scale. A bridge's overall condition is its lowest of those ratings, so one deteriorated component makes the whole bridge "poor."
A poor rating is not a closure. It means the bridge is flagged for priority repair or replacement; bridges judged unsafe are closed or posted with weight limits. The waterway (channel) rating is reported, but it does not count toward the overall classification.