SH 45
over SNAKE R.(WALTERS FERRY)
17 S. NAMPA, Owyhee County, Idaho
Condition
FairYear Built
1972
Daily Traffic
1,900
Length
69 ft
About This Bridge
SH 45 carries traffic over SNAKE R.(WALTERS FERRY) in Owyhee County, Idaho. Built in 1972, this structure is 54 years old, placing it among the older bridges still in active service. 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 1,900 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. Commercial trucks account for 17% of all crossings. This heavy commercial usage significantly impacts structural wear, as a single fully-loaded truck can cause as much deck wear as thousands of passenger vehicles. Transportation planners factor this into maintenance scheduling and budget allocation.
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 69 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
Deck Condition
Satisfactory
Superstructure
Satisfactory
Substructure
Satisfactory
Channel & Protection
Good
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 1972, this condition level is expected given the bridge's age and usage patterns. If this bridge were closed, traffic would face a detour of approximately 20 miles, underscoring the importance of maintaining this crossing.
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 State Highway Agency.
Construction
Dimensions
Span dimensions affect structural design choices and load distribution. The deck area of 2,527 sq ft determines surface maintenance scope.
Classification
Status
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.
1,900
Avg Daily Traffic (2022)
Vehicles per day crossing this bridge
17%
Truck Traffic
Commercial vehicle percentage
2,850
Projected Future ADT
Estimated future demand
This bridge carries approximately 1,900 vehicles per day, translating to roughly 693,500 crossings annually. Lower traffic volumes generally result in less structural wear over time.
Commercial trucks comprise 17% of traffic. Heavy vehicles cause disproportionate wear—a single fully loaded truck can have the impact of thousands of passenger cars on bridge deck surfaces. This high percentage of truck traffic may accelerate deterioration of deck surfaces and structural components.
Traffic projections estimate future volumes of 2,850 vehicles daily, a 50% 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
5.3 tons
Maximum allowable load for special permits
Inventory Rating
3.3 tons
Load level for normal traffic
The operating rating of 5.3 tons represents the absolute maximum load this bridge can carry under controlled conditions with special permits. The inventory rating of 3.3 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
↓DecliningCondition has declined by 1.0 rating points since 2020
Status Changes
- Reconstructed in 2020
Data: 2020-2024 FHWA National Bridge Inventory
Location
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44.122222, -116.891667
Identification
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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.