Category Archives: perception response time expert

Human Factors

Human Factors Engineering (aka Ergonomics) is the science of work, derived from the Greek ergon (work) and nomos (laws) .  Human Factors is a systems-oriented discipline which extends across all aspects of human activity, drawing on a number of scientific disciplines, including physiology, biomechanics, psychology, anthropometry, industrial hygiene, and kinesiology (U.S. Dept. of Labor, 2000)

  • Physical ergonomics is concerned with human anatomical, anthropometric, physiological and biomechanical characteristics as they relate to physical activity.
  • Cognitive ergonomics is concerned with mental processes, such as perception, memory, reasoning, and motor response, as they affect interactions among humans and other elements of a system.

human factors

Dr. John Lloyd attended Loughborough University in England, where he attained a BSc. with Honors in Ergonomics (1992) and Ph.D. in Ergonomics (2002). Loughborough University is considered a premier academic institute for the study of Ergonomics / Human Factors and is currently ranked #4 University in the UK, behind Oxford and Cambridge.

In addition, Dr. Lloyd has held the distinction of Board Certification since 1995 and is a member of the Human Factors and Ergonomics Society as well as the American Society of Biomechanics.

Dr. Lloyd has been accepted by the courts in Florida and other states as an expert in Human Factors and has provided testimony on:

Crash Data (EDR) Retrieval

Crash data retrieval (EDR) is a tool used by accident reconstructionists to download pre and post collision information from vehicles to determine driver behavior, impact severity and the cause of the crash.

Much like an airplane, almost all vehicles in the United States are equipped with a ‘black box’. In the event of an impact critical information about the crash as well as pre-crash information is recorded and stored in this black box, also known as an event data recorder (EDR). The process of obtaining this data is known as crash data retrieval.

It is a common misunderstanding that EDR data is only temporarily saved in the vehicle’s ‘black box’ and is erased after a short period of time. In the event of an airbag deployment, EDR data is almost always recorded and permanently stored. This data is never erased. Whereas, in a non-deployment event (i.e. airbags did not go off), if the event meets the manufacturer’s propriety algorithms to trigger recording, that data is saved, but can be overwritten if the vehicle is involved in subsequent collisions.

Motor vehicle crash data retrieval

crash data download from vehicle event data recorder

This information of vital importance when investigating a crash includes:

  • Speed
  • Change in Velocity (Delta-v)
  • Acceleration / Deceleration 
  • Braking 
  • Pre-crash Steering Inputs/ Angle
  • Seatbelt Usage and airbag deployment

crash data retrieval toolSpecialized equipment is required to access the EDR.

Unfortunately, law enforcement investigating a crash typically only retrieve the information from the Crash Data Recorder in the event of a traffic homicide. Hence, it is up to the accident reconstruction experts to download this information from the vehicles.

EDR data can help an accident reconstructionist to determine:

  1. pre-crash driver behavior
  2. crash severity
  3. who was at fault

Combined with his biomechanical expertise, Dr. Lloyd can use the information from the EDR to determine:

  1. occupant kinematics (motion in response to crash)
  2. whether injuries are consistent with crash severity

Distracted Driving Cell Phone Use

Many distractions exist while driving. Use of cellular phones while driving is a top distraction. Most new vehicles are equipped with hands-free technology, leading drivers to believe that talking via bluetooth is safe. However, this is not the case. In fact, human factors research shows that our brains remain distracted from the task of driving for several minutes even after hanging up a call. According to the National Safety Council, the use of cell phones while driving causes approximately 26% of motor vehicle crashes.

Lloyd human factors distracted driving crash

Human factors research shows that cell phone usage while driving is associated with increased reaction time, decreased situational awareness, more impulsive responses, and shrinks a drivers search area. Further, drivers exhibit less attention to objects even when looking directly at them. Moreover, “Impairments associated with using a cell phone while driving can be as profound as those associated with driving while drunk”. Hands free (Bluetooth) cell phone use is no less distracting than hand-held. What makes cell phone usage particularly dangerous is that drivers do not appreciate that their abilities are impaired due to distraction. Drivers distracted due to the use of cellular phones have little or no input to allow them to appreciate the things they did not see, or the things they looked at and did not process adequately.

Lloyd human factors distracted driving cell phone