Early warnings

June 1, 2005
TRUCK DRIVER personality traits, such as aggressiveness, impulsivity, and inattentiveness have high association with accident risk, according to a report

TRUCK DRIVER personality traits, such as aggressiveness, impulsivity, and inattentiveness have high association with accident risk, according to a report from the Transportation Research Board (TRB).

The report published in 2004, Individual Difference and the High-Risk Commercial Driver, was authorized by the Federal Motor Carrier Safety Administration (FMCSA).

Assessment of ways high-risk drivers can be targeted by various fleet and industry safety programs and practices is included in the report. It summarizes information on individual differences in driver safety performance and alertness, examines various metrics and tests that might be used to hire safer drivers and avoid higher-risk individuals, and identifies safety management techniques that are currently used by commercial vehicle carriers to target problem drivers and their specific risky behaviors.

However, the report summary points out that it is a presentation of findings, not a how-to guide on driver selection and screenings.

A variety of driver subjects are examined in the 94-page report.

Fundamental question

“Perhaps the most fundamental question about high-risk commercial drivers is whether the problem is genuine and significant, or the result of chance or other factors uncontrollable by commercial drivers and their fleets,” the report states. “Survey findings strongly support the notion that the problem is real and significant and that individual differences in safety among drivers are enduring.”

In one cited study, for example, large individual differences were seen in the rate of driver involvement in traffic near-miss incidents, and 12% of the drivers in the study were associated with 38% of the incidents. However, the study did not track drivers over a long period of time to determine the degree of consistency of differential risk or the personal traits that could produce enduring individual differences in risk.

Many factors affect accident involvement by drivers. The focus of this study was on enduring personal risk factors.

“Nevertheless, at any given time, commercial driver crash risk is affected by personal risk factors,” the report concludes, listing as examples hours of sleep the previous night and environmental factors such as weather and roadway conditions. One of the greatest risks is created by other drivers and traffic.

Accident prone

Accident proneness was originally conceptualized nearly 100 years ago. Early concepts of it considered it an innate, unitary trait, a view that is no longer widely held. However, it certainly appears that individual differences in personality and performance predispose some people to increased crash risk, the report points out. Driver errors can be violations of rules, mistakes of judgment, inattention, or inexperience.

Common driver errors contributing to crashes include recognition errors (failure to perceive a crash threat) and decision errors (risky driving behavior such as tailgating), or poor decision-making in dynamic traffic situations (such as trying to cross a stream of traffic).

Risk factors

The report includes factors related to commercial driver risk. A number of factors potentially correlate with risk and may be the basis for safety interventions to reduce risk.

Factors discussed include the following:

  • Driver age and gender
  • Driving history
  • Commercial driving experience
  • Longevity with employer
  • Crashes, violations, and incidents
  • Defensive driving
  • Non-driving criminal history
  • Medical conditions and health
  • Sleep apnea
  • Narcolepsy
  • Diabetes
  • Other medical conditions
  • Alcohol and drug abuse
  • Driver fatigue
  • Impulsivity and risk-taking
  • Social maladjustment and aggressive/angry personalities
  • Introversion-extroversion
  • Locus of control
  • Extreme (dichotomous) thinking
  • Sensory-motor performance
  • Stress
  • Recent involvement in other crashes
  • Safety belt use

Fleet safety management approaches to preventing high-risk-driver — related crashes revolve around the basic management functions of selection and hiring, performance evaluation, and driver safety management practices. The clearest advice to safety managers is, “Don't hire a problem,” the report states.

Once drivers are hired, there are various ways to monitor their driving behaviors and modify their behavior in ways that reduce risk. Performance evaluation and feedback (perhaps enhanced by on-board safety monitoring of driver behavior), training and counseling, performance incentives, behavior-based safety, and driver self-management are among the methods described. Of course, termination may be the ultimate solution when drivers are unmanageable from the safety perspective, the report adds.

Steps needed

Recommended research and development to address the problem of high-risk drivers includes the following:

  • Verification of the reliability of research findings indicating differential driver risk.

  • Determination of how enduring these differences are across time. To the extent that they are enduring, they constitute personal traits. To the extent that they change, they likely reflect short-term personal conditions (states) or purely situational factors.

  • The conducting of case control or other driver studies that profile individual driver differences within a group of drivers and relate these differences to safety outcomes (e.g., crashes).

  • Creation and field testing of various types of driver selection instruments.

  • Investigation of individual fatigue susceptibility. Research should verify that differences in fatigue susceptibility are long-term personal traits and identify ways to assess the level of fatigue susceptibility. Highly susceptible individuals should not be hired as commercial drivers or should receive special attention, including medical screening for sleep disorders and counseling about sleep habits.

  • Documentation of the best driver management practices for use by carrier safety managers and dissemination of this information throughout the industry.

  • Industry pilot testing of behavioral safety management techniques, perhaps enhanced by the use of on-board safety monitoring of driver safety performance and behaviors. This should include determination of the effectiveness of various management interventions including both positive rewards and negative discipline (punishment).

The report can be downloaded from a PDF file on the TRB Web site at trb.org/publications/ctbssp/ctbssp_syn_4.pdf.