COVERED BRIDGE RD

over FLAT RIVER

0.8 MI E OF BIGGS AVE, Kent County, Michigan

Condition

Fair

Year Built

1871

Daily Traffic

122

Length

10 ft

About This Bridge

COVERED BRIDGE RD carries traffic over FLAT RIVER in Kent County, Michigan. Built in 1871, this structure is 155 years old, making it a historic structure that has served the community for generations. The bridge features wood or timber construction with a truss - thru design, a combination chosen by engineers to meet the specific requirements of this crossing.

Approximately 122 vehicles cross this bridge daily, indicating lower traffic volumes common for local roads and rural routes. While traffic is lighter, these bridges still serve essential community transportation needs.

The bridge is currently rated in fair condition based on federal inspection criteria established by the Federal Highway Administration. The structure meets current safety standards for its designated use and load capacity. With a total length of 10 feet, this is a shorter span typical of local road crossings, often carrying traffic over small streams, drainage channels, or other roadways.

The construction materials used in this bridge were selected based on engineering requirements, cost considerations, and local conditions at the time of construction.

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

7

Deck Condition

Good

6

Superstructure

Satisfactory

7

Substructure

Good

8

Channel & Protection

Very Good

6

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 fair condition rating of 6 indicates satisfactory condition with minor section loss or deterioration.

For a structure built in 1871, this condition level is expected given the bridge's age and usage patterns.

Bridge Details

Wood or Timber is the primary structural material, which influences maintenance requirements and expected lifespan. The truss - thru design was selected based on span requirements, load capacity needs, and site conditions at the time of construction. Maintenance responsibility falls to County Highway Agency.

Construction

Year Built1871
Year Reconstructed1994
MaterialWood or Timber
Design TypeTruss - Thru
OwnerCounty Highway Agency

Dimensions

Total Length10 ft (3.0 m)
Max Span10 ft (2.9 m)
Deck Width2 ft
Deck Area164 sq ft

Span dimensions affect structural design choices and load distribution. The deck area of 164 sq ft determines surface maintenance scope.

Classification

Route TypeCounty Road
Route Number0
Lanes On Bridge2
Lanes Under Bridge

Status

Toll BridgeNo
Historical SignificanceOn National Register of Historic Places
Scour Critical3
Detour Length4 mi (6 km)

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.

122

Avg Daily Traffic (1996)

Vehicles per day crossing this bridge

Truck Traffic

Commercial vehicle percentage

220

Projected Future ADT

Estimated future demand

This bridge carries approximately 122 vehicles per day, translating to roughly 44,530 crossings annually. Lower traffic volumes generally result in less structural wear over time.

Traffic projections estimate future volumes of 220 vehicles daily, a 80% increase from current levels. These projections inform capacity planning and potential upgrade requirements.

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

0.3 tons

Maximum allowable load for special permits

Inventory Rating

0.3 tons

Load level for normal traffic

The operating rating of 0.3 tons represents the absolute maximum load this bridge can carry under controlled conditions with special permits. The inventory rating of 0.3 tons is the safe load limit for everyday traffic without restrictions. These relatively low ratings may result in posted weight limits or route restrictions for heavy vehicles.

5-Year Condition Trend

Declining

Condition has declined by 1.0 rating points since 2020

Data: 2020-2024 FHWA National Bridge Inventory

Location

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44.344444, -86.314167

Identification

Structure Number000000000005183
NBI IDMI-000000000005183
State FIPS26
County FIPS081

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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.

COVERED BRIDGE RD over FLAT RIVER | Michigan