US 378

over LITTLE RIVER

4.8MI SW OF MCCORMICK, McCormick County, South Carolina

Condition

Good

Year Built

2017

Daily Traffic

2,800

Length

99 ft

About This Bridge

US 378 carries traffic over LITTLE RIVER in McCormick County, South Carolina. Built in 2017, this structure is 9 years old, representing modern engineering and construction standards. The bridge features prestressed concrete continuous construction with a stringer/multi-beam or girder design, a combination chosen by engineers to meet the specific requirements of this crossing.

Approximately 2,800 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 16% 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 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 99 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

8

Deck Condition

Very Good

8

Superstructure

Very Good

8

Substructure

Very Good

8

Channel & Protection

Very Good

8

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 8, this bridge demonstrates very good condition with only minor issues.

For a structure built in 2017, maintaining good condition demonstrates effective maintenance practices. If this bridge were closed, traffic would face a detour of approximately 11 miles, underscoring the importance of maintaining this crossing.

Bridge Details

Prestressed Concrete Continuous 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

Year Built2017
MaterialPrestressed Concrete Continuous
Design TypeStringer/Multi-beam or Girder
OwnerState Highway Agency

Dimensions

Total Length99 ft (30.1 m)
Max Span11 ft (3.4 m)
Deck Width5 ft
Deck Area4,332 sq ft

Span dimensions affect structural design choices and load distribution. The deck area of 4,332 sq ft determines surface maintenance scope.

Classification

Route TypeUS Highway
Route Number378
Lanes On Bridge2
Lanes Under Bridge

Status

Toll BridgeNo
Historical SignificanceNot eligible
Scour Critical8
Detour Length11 mi (18 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.

2,800

Avg Daily Traffic (2022)

Vehicles per day crossing this bridge

16%

Truck Traffic

Commercial vehicle percentage

4,452

Projected Future ADT

Estimated future demand

This bridge carries approximately 2,800 vehicles per day, translating to roughly 1,022,000 crossings annually. Lower traffic volumes generally result in less structural wear over time.

Commercial trucks comprise 16% 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 4,452 vehicles daily, a 59% 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

5.2 tons

Maximum allowable load for special permits

Inventory Rating

3.4 tons

Load level for normal traffic

The operating rating of 5.2 tons represents the absolute maximum load this bridge can carry under controlled conditions with special permits. The inventory rating of 3.4 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

Loading map...

34.719722, -83.536944

Identification

Structure Number000000000000948
NBI IDSC-000000000000948
State FIPS45
County FIPS065

Explore More

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.

US 378 over LITTLE RIVER | South Carolina