HERBER RD

over LITTLE MAQUOKETA RIVER

090E22604, Dubuque County, Iowa

Condition

Good

Year Built

2015

Daily Traffic

1,908

Length

58 ft

About This Bridge

HERBER RD carries traffic over LITTLE MAQUOKETA RIVER in Dubuque County, Iowa. Built in 2015, this structure is 11 years old, representing modern engineering and construction standards. The bridge features prestressed concrete construction with a stringer/multi-beam or girder design, a combination chosen by engineers to meet the specific requirements of this crossing.

Approximately 1,908 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 good 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 58 feet, this is a shorter span typical of local road crossings, often carrying traffic over small streams, drainage channels, or other roadways.

Concrete bridges offer excellent durability and relatively low maintenance requirements. They resist corrosion well but can develop cracking over time, particularly in regions with freeze-thaw cycles or heavy use of deicing chemicals. Regular inspection focuses on detecting cracks, spalling, and reinforcement corrosion.

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

8

Deck Condition

Very Good

8

Superstructure

Very Good

7

Substructure

Good

7

Channel & Protection

Good

7

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.

With a lowest rating of 7, this bridge demonstrates good condition meeting all safety standards.

For a structure built in 2015, maintaining good condition demonstrates effective maintenance practices.

Bridge Details

Prestressed Concrete is the primary structural material, which influences maintenance requirements and expected lifespan. The stringer/multi-beam or girder 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 Built2015
MaterialPrestressed Concrete
Design TypeStringer/Multi-beam or Girder
OwnerCounty Highway Agency

Dimensions

Total Length58 ft (17.6 m)
Max Span12 ft (3.6 m)
Deck Width3 ft
Deck Area1,756 sq ft

Span dimensions affect structural design choices and load distribution. The deck area of 1,756 sq ft determines surface maintenance scope.

Classification

Route TypeCounty Road
Route Number0
Lanes On Bridge2
Lanes Under Bridge

Status

Toll BridgeNo
Historical SignificanceNot eligible
Scour Critical8
Detour Length2 mi (3 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.

1,908

Avg Daily Traffic (2021)

Vehicles per day crossing this bridge

Truck Traffic

Commercial vehicle percentage

1,908

Projected Future ADT

Estimated future demand

This bridge carries approximately 1,908 vehicles per day, translating to roughly 696,420 crossings annually. Lower traffic volumes generally result in less structural wear over time.

Traffic projections estimate future volumes of 1,908 vehicles daily, a decrease 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

6.5 tons

Maximum allowable load for special permits

Inventory Rating

4.6 tons

Load level for normal traffic

The operating rating of 6.5 tons represents the absolute maximum load this bridge can carry under controlled conditions with special permits. The inventory rating of 4.6 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

Stable

Condition has remained relatively stable since 2020

Data: 2020-2024 FHWA National Bridge Inventory

Location

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43.211944, -90.832222

Identification

Structure Number000000000148051
NBI IDIA-000000000148051
State FIPS19
County FIPS061

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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.

HERBER RD over LITTLE MAQUOKETA RIVER | Iowa