PIGEON KEY ACCESS

over KNIGHT CHANNEL

MARATHON KEY (MM 47), Monroe County, Florida

Condition

Poor

Year Built

1912

Daily Traffic

Length

1,048 ft

About This Bridge

PIGEON KEY ACCESS carries traffic over KNIGHT CHANNEL in Monroe County, Florida. Built in 1912, this structure is 114 years old, making it a historic structure that has served the community for generations. The bridge features steel construction with a girder and floorbeam design, a combination chosen by engineers to meet the specific requirements of this crossing.

Traffic data is recorded to help engineers understand usage patterns.

The bridge is currently rated in poor condition based on federal inspection criteria established by the Federal Highway Administration. It is classified as structurally deficient, meaning one or more components have received a rating of 4 or below on the 0-9 scale. This designation indicates significant deterioration that warrants attention, though the bridge remains safe for travel within its posted limits. Structurally deficient does not mean unsafe—rather, it signals that repairs or replacement should be prioritized in transportation planning. With a total length of 1,048 feet, this is a major span requiring specialized engineering expertise for inspection and maintenance. Longer bridges present unique challenges including thermal expansion, wind loads, and more complex structural analysis.

Steel bridges provide high strength-to-weight ratios, making them suitable for longer spans. However, they require ongoing protection against corrosion through painting or weathering steel designs. Inspectors pay close attention to connection points, fatigue cracking, and coating condition.

Federal law requires that all highway bridges be inspected at least every 24 months by qualified inspectors following the National Bridge Inspection Standards (NBIS). Some bridges with known issues or unusual characteristics may be inspected more frequently. Inspection data is reported to the National Bridge Inventory, a database maintained by the Federal Highway Administration that tracks the condition of all public highway bridges in the United States. This bridge data is sourced from that federal database and reflects the most recent available inspection results.

Condition Ratings

Structurally Deficient

This bridge has one or more component ratings of 4 or below, indicating significant deterioration that requires attention. The bridge remains safe for travel but may have load restrictions.

6

Deck Condition

Satisfactory

5

Superstructure

Fair

4

Substructure

Poor

8

Channel & Protection

Very Good

4

Lowest Rating

Determines condition category

NBI condition ratings range from 0 (failed) to 9 (excellent). Ratings of 4 or below are considered poor. The overall condition category is determined by the lowest individual component rating.

The substructure rating of 4 reflects significant wear in piers, abutments, or foundations.

For a structure built in 1912, the current condition reflects the cumulative effects of age, traffic, and environmental exposure.

Bridge Details

Steel is the primary structural material, which influences maintenance requirements and expected lifespan. The girder and floorbeam design was selected based on span requirements, load capacity needs, and site conditions at the time of construction. Maintenance responsibility falls to State Highway Agency.

Construction

Year Built1912
Year Reconstructed1938
MaterialSteel
Design TypeGirder and Floorbeam
OwnerState Highway Agency

Dimensions

Total Length1,048 ft (319.4 m)
Max Span8 ft (2.4 m)
Deck Width2 ft
Deck Area22,360 sq ft

Span dimensions affect structural design choices and load distribution. The deck area of 22,360 sq ft determines surface maintenance scope.

Classification

Route TypeOther
Route Number0
Lanes On Bridge1
Lanes Under Bridge

Status

Toll BridgeNo
Historical SignificancePossibly eligible
Scour CriticalU
Detour Length

Traffic Data

Traffic volume data helps engineers assess bridge wear patterns and plan maintenance schedules. Average Daily Traffic (ADT) counts are updated periodically and represent typical weekday usage.

Avg Daily Traffic (2023)

Vehicles per day crossing this bridge

Truck Traffic

Commercial vehicle percentage

Projected Future ADT

Estimated future demand

Load Ratings

Load ratings determine what weight this bridge can safely support. These values are critical for routing heavy vehicles and issuing overweight permits.

Operating Rating

Maximum allowable load for special permits

Inventory Rating

Load level for normal traffic

5-Year Condition Trend

Stable

Condition has remained relatively stable since 2020

Data: 2020-2024 FHWA National Bridge Inventory

Location

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25.284444, -81.698889

Identification

Structure Number900020
NBI IDFL-900020
State FIPS12
County FIPS087

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Data Source: Federal Highway Administration (FHWA) National Bridge Inventory 2024

Bridge inspection data is typically updated every 24 months. Conditions may have changed since the last inspection.

“Structurally deficient” does not mean a bridge is unsafe or likely to collapse. It indicates that one or more key structural elements are in poor or worse condition. Bridges are inspected regularly and may have load restrictions in place.

This data is for informational purposes only and should not be used for route clearance or vehicle weight decisions.

PIGEON KEY ACCESS over KNIGHT CHANNEL | Florida