FMCSA Study Analyzes the Causes of Commercial Truck Accidents

The Federal Motor Carrier Safety Administration (FMCSA) has found that the vast majority of commercial vehicle accidents are due to driver error. Researchers on the “Large Truck Crash Causation Study” also discovered that most crashes are complex and caused by a combination of factors. The study examined the structure of accidents and identified the various factors that resulted in accidents. Researchers then narrowed down the elements to determine the critical factors that were the tipping point which caused the crash. The study then identified the associated factors which contribute, but did not necessarily cause the collision.

Truck Accidents by the Numbers

The study limited its review to trucks with a gross vehicle weight of 10,000 pounds or more. Commercial vehicles were involved in approximately 120,000 fatal and injury crashes from April 2001 to December 2003 (a 33-month period). Of those 120,000 accidents, about 141,000 commercial trucks were involved. The study reviewed 963 crashes which involved 1,123 large trucks and 959 passenger vehicles and smaller trucks. The sampled crashes resulted in 249 fatalities and 1,654 injuries. According to the study results, about 25.8 percent of crashes resulted in fatalities.

Factors that Contribute to Truck Accidents

The FMCSA found that most crashes are rarely the result of one factor. The FMCSA study identified fatigue, speeding, and consuming alcohol as the three most common factors in vehicle crashes. Other variables include:

  • Road conditions
  • User errors
  • Weather conditions
  • Vehicle maintenance issues
  • Highway factors

Most accident reconstruction experts conclude that it is the confluence of multiple factors that results in a crash. The study defined causation as the combination of factors that lead to a collision. It divided causation into two broad categories: critical events and critical reasons.

Critical Events: the Tipping Point for Collisions

A critical event is an action or situation that ensured that the vehicle was unavoidably headed toward a crash. The FMCSA identified three critical events that were responsible for the majority of accidents.

First, 32 percent of accidents occurred when the truck ran out of the highway lane, either into another one or off the road. Second, 29 percent of truck accidents were caused by loss of control over the vehicle. The loss of control could have a variety of causes including cargo shifts, poor road conditions, speeding, and vehicle system failures. Finally, 22 percent of accidents were identified as rear-end collisions, primarily due to truck driver inattention or because a passenger vehicle did not give the truck sufficient time to slow down.

Critical Reasons that Cause Critical Events

A critical reason is the immediate cause of the critical event. The critical reason is the one factor that tipped the commercial truck into the critical event, resulting in the accident. According to the study, 87 percent of critical events are caused by driver mistakes. Driver mistakes are composed of four specific errors. First, 38 percent of accidents resulted when the driver made a mistake while driving — for instance, speeding, failing to signal or following another vehicle too closely.

Additionally, 28 percent of accidents were caused by the driver failing to recognize and respond to a dangerous condition. For example, drivers who are distracted or inattentive while driving often fail to observe and respond to road conditions. Furthermore, 12 percent of driver-related accidents were caused by the driver failing to perform correctly — for example, drivers who fall asleep, suffer heart attacks or become physically impaired.

Finally, nine percent of driver-related accidents were caused when the driver exercised poor judgment on the road. For instance, the driver overcompensates, fails to exercise directional control, panics during an emergency.

A further 10 percent of accidents were caused by an environmental factor. Environmental factors cover anything that is not related to the driver or the vehicle. These include poor road conditions, like potholes, and weather concerns, like rain, snow, or fog.

Finally, three percent of accidents were caused by vehicle failures. Vehicle failures were caused by poor maintenance and design or manufacturing flaws. The low numbers of vehicle-caused accidents suggest that the vast majority of accidents are caused by driver error or environmental factors.

Associated Factors for Critical Events

The researchers compiled hundreds of associated factors that contributed to commercial truck crashes. The study identified a variety of factors including, but not limited to, drug abuse (both over the counter and prescriptions), poor roadway conditions, traffic congestion, speeding, blind spots, and inattentive driving due to fatigue. Additionally, vehicle malfunctions, specifically brake failures, were another common cause.

Commercial Truck and Passenger Vehicle Accidents

Commercial trucks are responsible for a disproportionate number of fatalities, relative to the number of trucks on the road. The FMCSA study clarified that technology and training that focuses on reducing driver errors are crucial to reducing the number of fatalities.