Thursday, May 21, 2020 from 12:00 PM to 1:00 PM MDT
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This is an online event. 



Bo Donegan 
Colorado Defense Lawyers Association 

Join us online for our Lunch & Learn Presentation! 

Human Factors in Transportation Cases: 
A Case Illustration 
Thursday, May 21 from 12-1:00 p.m. 

Presented by:
Nancy Grugle, Ph.D. CHFP 
Exigent Group Limited: Forensic Consulting Division
Human Factors Expert 

1 hour CLE applied for 

Sponsored by:


This 60-minute presentation by Dr. Nancy Grugle uses a case illustration to discuss several human factors topics related to transportation cases including Visibility/Conspicuity, Looming, Attention, Driver Actions, Drowsy Driving, and Distracted Driving. Dr. Grugle will also discuss the scientific methods and techniques used in human factors investigations of transportation cases. There will be opportunities to ask questions about current cases you have. 


  • The visibility of objects that are within a person’s line of sight is a function of several factors including visibility and conspicuity. There is not always a clear distinction between visibility and conspicuity, but many of the same factors that affect visibility also affect conspicuity. These include movement, color and color contrast, luminance contrast, object size, and the location of the object in the driver’s field of view. 


  • A driver’s ability to avoid rear-ending a slow-moving or stopped lead vehicle depends on a number of factors, but often depends on a driver’s ability to detect their rate of closure to the slow-moving vehicle. 
  • A human factors investigation of a rear-end collision involving a slow-moving or stopped vehicle on a highspeed road includes calculating the point of looming detection, determining the appropriate perception-reaction time for the driver, and analyzing whether there was sufficient information available in the roadway environment for a driver to determine that the lead vehicle was either stopped or moving slowly. 

 Drowsy driving: 

  • Drowsy driving research has found that time of day is the single most important factor contributing to fatigue and reduced alertness when driving and is the single best predictor of drowsy driving crashes. 
  • Human factors investigations of drowsy driving crashes consider the underlying scientific causes of sleep deprivation and fatigue to answer two main questions-was the driver fatigued or sleep-deprived at the time of the crash and was fatigue or sleep deprivation a cause of the crash? 

 Distracted driving: 

  • In general, distracted driving is any activity that diverts attention away from activities critical for safe driving. The effects of distracted driving on driver performance include the following: increased time that eyes are off road, increased reaction time to hazards, increased braking reaction time, greater speed variability and slower mean speed, increased lane deviations and lane departures, and closer car following. 
  • A human factors expert uses a combination of techniques, knowledge of human behavior and performance, and experience investigating vehicle collisions to determine if the driver was exhibiting the know effects of distraction at the time of the collision, if the driver was distracted, and if distraction was a cause of the collision. 

About the speaker 

Dr. Nancy Grugle is an expert in human factors and ergonomics. She investigates the way in which human performance is affected by factors including fatigue, distraction, and impairment and how performance is impacted by the design of technology and the work environment. Dr. Grugle has academic, research and industry experience in human factors engineering research and design. She was awarded competitive human factors research grants from the National Science Foundation, the Ohio Department of Transportation, and the Cleveland State University Transportation Center and her research has been published in national and international peer-reviewed journals. Dr. Grugle conducts investigations for both plaintiff and defense counsel and has testified in both state and federal courts. 

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