Human Factors

The Department of Human Factors at the National Biomechanics Institute (NBI) provides expert witness testimony in civil and criminal courts for both defense and plaintiff attorneys. NBI human factors team works across different sectors, and also provides consulting on human behavior and human error to insurance agencies, municipalities, and government entities.
Our experts rely on scientific knowledge of psychological, behavioral and engineering approaches and methods to help clients understand how people interact with, and react to, the environment and/or technology. We base our technical, forensic opinions upon various psychological principles such as cognition, information processing, decision-making, sensation, perception, attention and memory to analyze how people think and make decisions across different contexts.
NBIhuman factors team is comprised of individuals with expertise in various areas of psychology (experimental, organizational, educational, clinical), as well as other related fields such as cognitive science, behavioral neuroscience, medical science, physiology, pharmacology, kinesiology, and engineering.
Peer-reviewed data and case facts, and the use of widely accepted scientific methodologies, enable human factors experts at NBI to identify the cause of the accident, as well as to offer advice on reducing unsafe behaviors and practices. The application of knowledge about human behavioral and cognitive characteristics, abilities, and limitations provides an in-depth understanding of how people perform in various environmental conditions.

We use our academic research and industry experience to investigate human factors across various complex scenarios including, but not limited to:

Automobile, commercial truck, and motorcycle accidents;
Bicycle and pedestrian accidents;
Slip and trip-and-fall, and over-step and misstep incidents;
Industrial and occupational accidents (e.g., construction and workplace safety, and environmental health);
Injuries associated with consumer products usage (e.g., product design, labels and information, and safety warnings and communications).

Our scientific expertise includes the analysis of:

Driver accident avoidance strategies;
Speeding in accident causation;
Perception-reaction time and stopping sight distance requirements;
Driver judgement of speed and distance of other vehicles;
Driver “blind spots”
Driver behavior and distraction, and use of in-vehicle technologies;
Driving and the effects of weather phenomena (e.g., rain, fog, dust, and snow);
Driving and the effects of glare from sun and headlights;
Pedestrian perception and behavior;
Behavioral and cognitive effects of alcohol and marijuana;
Behavioral and cognitive effects of fatigue, sleep deprivation, and shift work;
Behavioral and cognitive effects of OTC medications (e.g., opioids, benzodiazepines, anti-depressants) and illicit drugs;
Cognitive load, and working memory failure;
Cognitive expectancy, reaction time and response selection;
Sensory detection, and perceptual ability and failure (e.g., visibility, visual disturbance, motion processing);
Illumination, nighttime visibility, and pedestrian conspicuity;
Monocular vision, and depth perception and field of view;
Awareness, attention and distraction (e.g., inattention blindness, visual attention, visual search behavior);
Advance traffic warning signs, and risk perception and hazard anticipation;
Situational awareness, and individual differences;
Motor behavior, movement control, gait, coordination, and loss of balance;
Slip resistance, changes in walkway level;
Ergonomics, and workplace layout;
Product and equipment design-induced errors;
Design and maintenance of roadways, work zones, and parking lots;
Design and maintenance of floors, ramps, stairways, and stair handrails;
Design and maintenance of signs and lighting;
Eyewitness identification, perception, and memory precision and bias;
Police-involved shootings, and excessive force;
False confessions, and police interrogation tactics;
Decision-making, performance and memory under conditions of acute or chronic stress;
Age-related changes in behavior, performance, cognition, and learning and memory;
Psychosocial development, and adolescent risk-taking behavior and impulsivity.

In our work, we use the following tools to assess factors that affect human behavior, performance, and error:

Luminance meter for measuring photometric brightness;
Rangefinder for assessment of distance;
Interactive Driver Response Research (I.DRR) software for including human factors in accident reconstruction process

Additional information on tools and software that NBI human factors experts use in their forensic work:

Luminance meters are detectors that measure photometric brightness (i.e., they measure the amount of light reflected to the eye from the object and its background). “Luminance” refers to the amount of light that is available for vision. Human factors experts, for example, may use these detectors to measure object contrast, which refers to the relationship between the luminance of an object and the luminance of the object’s background.
Through a process of ranging, the rangefinder device is used to assess distance from the observer to a target. Estimating distance is an essential part of nearly every human activity such as walking or driving. The key to safe driving is anticipation, and, for example, a driver could hardly perform effectively without a reasonably accurate knowledge of her distance from the vehicle in front to calculate a safe following distance on the road.
I.DRR software allows for inclusion of human factors in the process of accident/crash reconstruction. This software allows human factors experts to evaluate various factors such as age, gender, disability, fatigue, temporary distraction, general visibility, glare and dark adaptation that impact cognition, perception, reaction time and behavior in the context of driving performance.

Human factors in driving performance, road safety, and accident investigation

There are more than 6 million police-reported traffic crashes annually, resulting in more than 1.7 million injuries and 32,000 fatalities. The medical bills and productivity losses associated with crash injuries and deaths exceed $63 billion in a one-year period. Statistics show that human-related behavioral factors are the single most important cause across all traffic accidents.

Human factors influence the probability of traffic accidents:

Various factors influence driving capability by shaping visual perception, judgment, decision making, and reaction time. Factors like inexperience, advanced age, disability and chronic disease can reduce capability for an extended period of time, whereas fatigue, sleep deprivation, temporary distraction, and acute stress or alcohol/drug intoxication are typically associated with short-term reduction of capability.

Perception-reaction time (PRT) and brake/steering response analysis:

The time needed to respond to a stimulus while driving must be estimated correctly. NBI experts rely on their professional experience, academic education, primary research, and peer-reviewed data whileexamining the facts of a particular casein order to estimate driver response times and the total stopping sight distance.The following are some of the variables that have an influence on response time while driving:

Direction from which the hazard emerges (e.g., rear-end accident);
Time to collision (e.g., car following distance);
Traffic density (e.g., rush-hour traffic);
Time of day and lighting (e.g., nighttime);
Roadway surface and weather conditions (e.g., rain, fog);
Driver distraction (e.g., in-vehicle technologies, passengers);
Driver characteristics (e.g., inexperience, advanced age);
Driver medical history (e.g., diabetes, cataracts).