Logistics

The Trucking Safety Landscape: Patterns from Nearly 20 Million DOT Inspections

Analysis of inspection data from January 2021 through July 2025

The commercial trucking industry undergoes rigorous safety oversight through the Department of Transportation's inspection program. We analyzed 19,626,853 inspection records conducted between January 27, 2021, and July 8, 2025, representing 893,920 unique DOT numbers across 57 states and territories. Of these inspections, 23.8% resulted in violations, with 13.47 million total violations and 5.42 million out-of-service orders issued.

Key Takeaways

Truck age drives risk: Vehicles over 20 years old average 2.9 violations vs. 1.2 for <5-year trucks.
Enforcement varies by state: Violation rates span 12.1% (MS) to 36.0% (WI)— reflecting potential difference in geographies and enforcement focus areas.
Maintenance dominates: 69% of violations are maintenance-related; 42% of those are critical (brakes, steering, tires).
Fleet type matters: Owner-operators face 1.3× higher OOS risk than large fleets.
Inspection intensity: Level 1 full inspections uncover nearly 3× more violations than credential checks.

Geographic Patterns: Where You Operate Matters

Violation rates vary dramatically by location, ranging from 12.1% in Mississippi to 35.7% in Wisconsin—a three-fold difference that has real implications for route planning and fleet deployment.

Highest violation rates:

Wisconsin: 35.7%
Massachusetts: 35.6%
Iowa: 34.9%
Michigan: 34.2%
Connecticut: 33.9%

Lowest violation rates:

Mississippi: 12.1%
North Carolina: 12.6%
Illinois: 13.6%
South Dakota: 15.7%
New Mexico: 16.9%

Regional analysis shows the Southwest averaging 27.6% violation rates, while the West performs best at 20.7%.

Maintenance Drives the Violation Landscape

Vehicle maintenance violations dominate safety enforcement, accounting for 9.28 million violations—69% of all safety issues. This overwhelming proportion reveals where the industry's biggest systematic challenges lie:

Vehicle Maintenance: 9,276,432 violations (69%)
Driver Fatigue: 1,341,509 violations (10%)
Unsafe Driving: 1,280,779 violations (9.5%)
Driver Fitness: 615,170 violations (4.6%)
Hazmat: 83,365 violations (0.6%)
Substance/Alcohol: 39,617 violations (0.3%)

The correlation between violations and out-of-service orders was strong at 0.638, indicating that vehicles with violations face significantly higher likelihood of being sidelined.

Vehicle Age: The Deterioration Curve

Truck age drives risk with mathematical precision. The correlation coefficient of 0.223 between age and violations reveals a predictable deterioration pattern:

0-5 years: 1.20 violations, 15.3% out-of-service rate
6-10 years: 1.72 violations, 20.4% out-of-service rate
11-15 years: 2.30 violations, 24.0% out-of-service rate
16-20 years: 2.73 violations, 26.3% out-of-service rate
20+ years: 2.90 violations, 27.4% out-of-service rate

Trucks over 15 years old face 1.33 times higher violation risk than newer vehicles, with the oldest trucks averaging 2.4 times more violations than the newest.

Fleet Size and Safety Performance

Analysis of carrier data revealed clear patterns based on fleet size, with larger operations consistently demonstrating better safety performance. Owner-operators with single trucks showed a 30.3% violation rate, while small fleets of 2-5 trucks performed slightly worse at 30.5%. As fleet size increased, violation rates dropped significantly: medium fleets of 6-20 trucks achieved a 27.3% violation rate, large fleets of 21-100 trucks improved to 23.4%, and very large fleets with 100+ trucks demonstrated the best performance at just 19.0% violation rates.

Violation rates by fleet size:

Owner-operators (1 truck): 30.3% violation rate
Small fleets (2-5 trucks): 30.5% violation rate
Medium fleets (6-20 trucks): 27.3% violation rate
Large fleets (21-100 trucks): 23.4% violation rate
Very large fleets (100+ trucks): 19.0% violation rate

This data reveals a consistent inverse relationship between fleet size and violation rates, with larger fleets demonstrating superior safety performance across all categories. The gap between the smallest and largest operations is substantial, with very large fleets showing violation rates nearly 40% lower than owner-operators and small fleets.

When Inspections Happen: Weekly Patterns

Commercial vehicle inspections follow distinct weekly rhythms. Wednesday represents peak activity at 21.4% of weekly inspections, with Tuesday close behind at 21.3%. Weekend enforcement drops dramatically—Sunday accounts for just 3.3% of weekly inspections.

Weekly inspection distribution:

Wednesday: 21.4% (peak activity)
Tuesday: 21.3%
Monday: Moderate activity levels
Thursday: Declining from midweek peak
Friday: Further reduction
Saturday: Significant drop-off
Sunday: Just 3.3% of weekly inspections

Notably, weekend inspections demonstrate lower violation rates than weekday inspections, potentially reflecting reduced commercial traffic, different fleet types operating weekends, or varying enforcement priorities during off-peak periods.

Inspection Intensity: You Find What You Look For

The depth of inspection directly correlates with violation discovery:

Level 1 (Full inspection of vehicle and driver): 2.23 average violations
Level 2 (Walk-around inspection): 2.02 average violations
Level 3 (Driver credentials only): 0.80 average violations

Level 1 inspections uncover nearly three times more violations than credential checks, highlighting the importance of vehicle condition for operators facing comprehensive inspections.

Hazmat Operations: A Counterintuitive Finding

Despite representing only 2.7% of inspections, hazmat vehicles show a notably lower out-of-service rate (12.6%) compared to non-hazmat operations (18.4%). This likely reflects the additional training, certification, and oversight required for hazmat operations.

Risk Factors Compound

Analysis of risk factors across all inspections reveals how dramatically exposure compounds:

Low Risk: 0.74 violations, 5.4% OOS rate
Moderate Risk: 1.64 violations, 22.8% OOS rate
High Risk: 2.11 violations, 19.9% OOS rate
Highest Risk: 3.73 violations, 36.2% OOS rate

The highest-risk category shows 5x more violations and 6.7x higher OOS rates than low-risk inspections.

Vehicle age is a major factor - Trucks 15+ years old face 1.33x higher violation risk
Geography matters - Operating in high-enforcement states multiplies your exposure
Timing affects risk - Mid-week operations face more intensive enforcement
Maintenance history compounds - Previous violations predict future problems

Key Takeaways for Industry Stakeholders

This analysis of 19.6 million inspections offers clear, actionable insights for everyone in the trucking ecosystem:

For Fleet Operators:

Vehicle maintenance represents 69% of all violations—prioritize preventive maintenance programs
Trucks over 15 years old face 33% higher violation risk—factor age into replacement decisions
Midweek operations face peak enforcement exposure—ensure compliance readiness Tuesday-Wednesday

For Freight Brokers:

Geographic variation spans 3x between states—factor regional enforcement intensity into carrier selection
Fleet size strongly correlates with safety performance—larger carriers show consistently lower violation rates
Vehicle age serves as a reliable safety performance indicator

For Equipment Vendors and Service Providers:

Maintenance-related violations represent the largest market opportunity for safety improvement
Age-related deterioration creates predictable demand cycles for parts and services
Small fleets and owner-operators show higher violation rates, indicating concentrated service needs

For Route Planning:

Tuesday-Wednesday corridor represents peak enforcement exposure
Weekend operations benefit from reduced inspection frequency but potentially more targeted scrutiny
Geographic patterns provide predictable enforcement intensity for strategic routing

This analysis of 19.6 million inspections provides a data-driven foundation for operational decisions across the trucking ecosystem. Understanding these patterns—from the 69% maintenance violation dominance to the 3x geographic enforcement variation—enables smarter fleet management, carrier selection, and service positioning strategies.

This analysis represents observed patterns in publicly available DOT inspection data and should inform rather than replace comprehensive safety and compliance programs.