Conference Proceeding

Three Large Truck Crash Categories: What They Tell Us About Crash Causation

  • Ronald R Knipling (Human Factors & Traffic Safety Consultant, Arlington, VA)


Large Truck Crash Causation Study (LTCCS) data is used to compare three categories of crash involvements: truck single-vehicle (SV) involvements, multi-vehicle (MV) involvements in which the truck has been assigned the critical reason (CR), and MV involvements in which the other vehicle (OV) has been assigned the CR. These three categories represent distinctly different causal contributions by truck drivers to the crash, with SV involvements having the greatest truck driver impairment and misbehavior. Surprisingly, paired comparisons of the three categories indicate that truck SV and truck-CR MV crash involvements were the most dissimilar in their causal profiles. Factors associated with truck SV crash involvements include non-use of safety belts, driver unfamiliarity with roadways, vehicle failures, lack of prior sleep, 16+ hours awake, and early morning driving. Dense traffic situations (e.g., rush hours) make trucks more likely to be at-fault in MV crashes. Many other factors were not associated with differences among the categories, suggesting no differential effect on truck driver safety performance, even though they might affect risk generally. Among fatigue-related factors, those related to sleep and alertness physiology were linked to SV crashes, while those related only to Hours-of-Service (HOS) work rules were not.

How to Cite:

Knipling, R., (2009) “Three Large Truck Crash Categories: What They Tell Us About Crash Causation”, Driving Assessment Conference 5(2009), 31-37. doi:

Rights: Copyright © 2009 the author(s)

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Published on
23 Jun 2009
Peer Reviewed