EW #219 is a board-certified professional ergonomist with more than 30 years' experience as a human factors/ergonomics specialist. A graduate of the University of California at Santa Barbara , he joined the pioneering firm of Human Factors Research, Inc. in 1967, where his mentors in human factors were some of the founders of that branch of science. He specialized in vigilance and operator performance, and in the last 15 years has focused on human factors in driving. He was Vice President and Senior Staff Scientist of Human Factors Research, Inc., and a Principal Scientist at Essex Corporation before starting his own firm in 1997. His  curriculum vitae is available upon request.)

Driver Fatigue, Driving Safety, and Forensic Human Factors Analysis for Accident Reconstruction
Driver fatigue is a significant cause of traffic accidents. In truck and bus accident litigation, claims based on driver fatigue are being made in increasing numbers. Defense and plaintiff's attorneys who deal with fatigue claims should consult a forensic driver fatigue expert. The forensic expert should be competent in:

1. the nature and relative importance of the various causes of driver fatigue, and the specific effects of fatigue on driver performance;
2. the human factors engineering and scientific aspects of driving safety, including driver skill and knowledge requirements for the various classes of vehicles, the basis of the Commercial Driver License (CDL) system, and the safety responsibilities of truck and bus drivers and motor carriers;
3. forensic human factors analysis for accident reconstruction.

For more information about these areas, click on the highlighted words above or the topics in the left margin.

Forensic Human Factors Analysis for Fatigue Accident Reconstruction
There is no breath analyzer or blood test that can reveal the presence of a critical level of fatigue in an accident-involved driver. However, a forensic driver fatigue expert can often conclude to a reasonable degree of scientific certainty whether fatigue was a cause of the accident, by doing a human factors accident reconstruction involving two important steps:

1. a forensic human factors analysis of the driver's work-rest history leading up to the accident, and
2. a forensic human factors analysis of each particular aspect of the driver's performance that may have been a cause of the accident.

These steps are discussed in turn below.

Theoretically, a commercial driver's work-rest history will be adequately documented in the "driver's record of duty status" required by the Federal Motor Carrier Safety Regulations (49 C.F.R. § 395.8), substantiated by regular work hours and personal routine. Unfortunately, this is not always the case. The driver's work hours may be very irregular. The driver's log may be days in arrears, or may be missing altogether. Even if present, the log may be inaccurate or falsified, so it must be tested against other sources. The forensic driver fatigue expert examines up to 27 different categories of documents and records using specific tools and techniques, reconstructs the driver's probable work-rest history, and describes that history in terms of implications for specific factors of driver fatigue.

The expert then studies the particular nature of the driver's performance that may have been a cause of the accident. This will involve forensic analysis of the driving environment and the driver's apparent actions in the time period leading up to and including the accident, as related by witnesses, indicated by analyses of physical evidence, and inferred from reconstructions based on engineering and physics. The expert must characterize the driver's performance with regard to numerous specific human factors elements of driving.

These forensic human factors analyses for fatigue accident reconstruction often permit the forensic driver fatigue expert to identify specific deficiencies of driver performance, to decide whether any of these deficiencies were fatigue related, and to conclude to a reasonable degree of scientific certainty whether fatigue was (or was not) a cause of the accident.