MD 4
Carrying MD 4 over PATUXENT RIVER & TOWN CR
ON ST MARYS CO LINE, Calvert, Maryland
Data updated May 2026
FHWA NBI record, refreshed with each annual release.
Bridge Snapshot: MD 4
The MD 4 bridge in Calvert, Maryland carries MD 4 over PATUXENT RIVER & TOWN CR. It was built in 1977, making it 49 years old today. The structure is built primarily of steel continuous and spans 9 sections, stretching 2196.7 meters (7207 feet) end to end. Daily traffic averages 28,338 vehicles, placing it in the heavily-trafficked tier of Maryland bridges. It is owned and maintained by State Highway Agency.
The latest FHWA inspection records show a deck rating of 6/9, superstructure at 5/9, substructure at 6/9. The weakest component sits in fair condition. No reported major component scores in the Poor range under the current federal condition thresholds. Its NBI inventory load rating is 20.4 metric tons.
Sourced from the FHWA National Bridge Inventory. See our methodology for refresh cadence and NBI release vintage.
How MD 4 compares
Live comparison across Maryland.
Historical Sufficiency Rating
PlainBridge-computedFHWA discontinued this calculated item; it does not determine current condition, funding eligibility, posting, or closure. How the historical reference is calculated.
Condition Ratings
Full 0–9 scale + sufficiency-rating breakdown: how condition ratings work.
Structural Details
- Year Built
- 1977
- Material
- Steel Continuous
- Number of Spans
- 9
- Structure Length
- 2196.7 m (7207 ft)
- Deck Width
- 9.5 m (31 ft)
- Owner
- State Highway Agency
- Avg Daily Traffic
- 28,338 vehicles/day
- Structure Number
- 100000040019010
Location
Data Source
FHWA National Bridge Inventory (NBI).
FHWA NBI Program ↗Condition Analysis
- • At 6/9, the deck (driving surface) shows fair condition, with minor wear flagged for upkeep.
- • The superstructure (beams and supports above the deck) rates fair at 5/9, minor deterioration that routine maintenance should address.
- • The substructure (piers and abutments) is in fair condition (6/9), with minor deterioration that may require routine maintenance.
How to read this record
This page shows what the last federal inspection recorded, not whether MD 4 is safe to cross today. Here is how to use it.
- NBI condition ratings reflect the latest record in this annual dataset, not a live status. Current routine inspection intervals are risk-based.
- Learn how the 0–9 condition scale and Good/Fair/Poor categories are defined. How condition ratings work
- Compare MD 4 against other structures in Calvert and across Maryland. Maryland bridges
- Noticed visible damage or a safety concern? Report it to the agency that owns the bridge, or call 911 in an emergency. How to report a bridge
Condition codes come straight from the FHWA National Bridge Inventory and are not a real-time safety judgment. Only the owning agency, a state DOT, county, or other owner, can post, restrict, or close a bridge.
Frequently Asked Questions
What do the condition ratings mean for MD 4?
MD 4 in Calvert, Maryland has a deck rating of 6/9, superstructure rating of 5/9, and substructure rating of 6/9 on the FHWA's 0–9 scale.
How often is MD 4 inspected?
MD 4's responsible agency sets its routine interval under FHWA's risk-based inspection rules; this page does not expose the scheduled interval. It carries about 28,338 vehicles per day.
What does “structurally deficient” mean in older bridge reports?
FHWA retired that reported status beginning with the 2018 archive. MD 4 is currently shown as Fair condition from its component ratings; that category is not a live closure or safety decision.
What is the inventory load rating for MD 4?
MD 4 has an NBI inventory load rating of 20.4 metric tons.
Who is responsible for maintaining MD 4?
MD 4 is owned and maintained by State Highway Agency.
How old is MD 4 and does age affect safety?
MD 4 was built in 1977, making it 49 years old.
Disclaimer: Bridge condition data is from the FHWA NBI and reflects the last reported inspection. A Poor condition rating is not a live declaration that a bridge is closed or unsafe for travel. For current closure, posting, or safety information, contact the responsible transportation agency.
Every figure on PlainBridge is rendered directly from federal source data, no number is typed in by an editor. This page draws directly on federal source data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.