Category Archives: driving human factors

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 Texting

Distracted driving is any activity that diverts attention from driving, including talking or texting on your phone, smoking, eating and drinking. I have even seen people putting on makeup and shaving their face while driving!Lloyd human factors expert distracted driving texting

Texting is the most alarming driver distraction. Sending or reading a text takes your eyes off the road for 5 seconds or more. At 40 miles per hour a car can travel the length of a football field in 5 seconds; at highway speeds, a vehicle can travel the length of almost two football fields in the same time.

Texting while driving and other cell-phone reading and writing activities are high-risk activities associated with motor vehicle collisions and mortality. In 2015 alone 3,450 people were killed on US roads. 391,000 were injured in motor vehicle crashes involving distracted drivers.

There are three types of driver distractions – manual, visual and cognitive.

  • Manual distractions cause you to take your hands off the steering wheel
  • Visual distractions cause you to take your eyes off the road
  • Cognitive distractions interfere with your mental focus on driving

Texting involves all three of the above distractions and is therefore considered a high risk activity while driving.

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