A firm size and safety performance profile of the U.S. motor carrier industry.

Cantor, David E.; Osborn, Ethan; Singh, Prabhjot · 2014 · ROSA P / Iowa State University. Institute for Transportation

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Summary

This study investigates the relationship between firm size and safety performance within the U.S. motor carrier industry, addressing a gap in literature regarding how carrier characteristics influence driver involvement in state-reportable crashes. The research is motivated by the observation that smaller carriers, which constitute the majority of the industry, often lack resources for robust safety monitoring, potentially leading to higher violation rates. The study aims to develop a profile that helps the Federal Motor Carrier Safety Administration (FMCSA) better target carriers with serious safety violations. The researchers constructed a comprehensive database using FMCSA’s Motor Carrier Management Information Systems (MCMIS) and Safety Measurement System (SMS) data from June 2014. The sample included approximately 462,725 interstate motor carriers with complete data. Firm size was operationalized as the number of power units, categorized into 12 distinct groups ranging from single-unit firms to those with 91+ units. Safety performance was measured using driver and vehicle out-of-service (OOS) rates, crash rates (per power unit and per vehicle mile traveled), and seven Behavior Analysis and Safety Improvement Categories (BASICs), including unsafe driving, hours of service (HOS), driver fitness, vehicle maintenance, controlled substances/alcohol, hazardous materials compliance, and crash history. The analysis employed descriptive statistics, analysis of variance (ANOVA), and Ordinary Least Squares (OLS) regression to examine relationships between firm size, commodity segments, fleet ownership, and safety outcomes. The findings reveal a strong inverse relationship between firm size and violation rates: as firm size increases, both driver and vehicle OOS rates decline significantly. For instance, the mean driver OOS rate dropped from 0.0862 for the smallest firms to 0.0313 for the largest. Similarly, larger firms exhibited better performance in HOS compliance, vehicle maintenance, and hazardous materials compliance. However, crash rates showed an upward trend as firm size increased, with the largest firms having higher crash rates per power unit and per mile than the smallest firms. Fleet ownership also influenced safety; generally, higher ownership percentages correlated with improved safety performance in most BASICs, though patterns varied by specific metric. Commodity segments also showed significant differences in safety performance, with certain sectors like logs and lumber exhibiting distinct safety profiles compared to general freight or motor vehicles. The study concludes that firm size is a critical determinant of safety performance, particularly regarding regulatory compliance and violation rates. Larger carriers demonstrate superior adherence to safety regulations, likely due to greater resources for monitoring and implementation of safety practices. Conversely, the higher crash rates among larger firms may reflect greater exposure or different operational risks. These findings provide empirical evidence to support targeted regulatory enforcement and suggest that future safety models should account for firm size and structural characteristics to effectively mitigate risks in the motor carrier industry.

Key finding

Driver and vehicle out-of-service rates decreased as firm size increased, whereas crash rates per power unit and per vehicle mile traveled increased with firm size.

Methodology

dataset

Sample size: 462725

Provenance

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Topics

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• bus coach
• fleet safety
• truck driver fatigue

Information type

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• Empirical Findings: crash risk outcomes