Case 4  Front-seat occupant is killed, whereas rear-seat passenger is uninjured
  [Outline of Accident]
  Car A (passenger car) was traveling on a 4.6-m-wide two-lane road, gently curving to the left, at about 2:00 a.m. in cloudy weather. The driver of the car (male in his 20s) somehow drove the car off the road to the right, and right front of the car hit a tree , after which the left front of the car hit a utility pole.
  The driver was not wearing a seat belt. The passengers, a male in his 20s seated in the front, and two other males in their 20s seated in the rear, sensed danger at the speed of the car and fastened their seat belts shortly before the collision. The speed at which the car crashed was estimated to have been about 100 km/h.

[Damage to the car]
  Extensively damaged (maximum 170-cm deformation on the right front)
  Car interior deformation: maximum 47 cm
  Equivalent barrier speed *: unknown

[Impact of collision; injury to occupants]
- Driver
  He jerked forward when the car rammed into the tree and then into the utility pole, and his head crashed against the right A-pillar. He died from acute epidural hematoma, brain swelling and other injuries.
- Front-seat passenger
  Although he suffered bruising from the pressure of the seat belt, he escaped from collision against the carq¡¦ interior, as he was restrained in the seat.
- Rear-seat passenger on the right
  His chest was bruised from the pressure of the seat belt. However, with his body restrained, he did not hit any object of the car's interior and ended up with broken ribs only.
- Rear-seat passenger on the left
  With his seat belt on, he avoided hitting any object of the car's interior, and came out of the accident unharmed.

Fig. 8  Accident Diagram

Photo 7  Deformation of Car A

Photo 8  Damage to Car A's driver's seat
* The door was removed by the rescue squad.

Fig. 9
Position of Car A's occupants; restraint; injury severity

  The driver, not restrained by a seat belt, smashed against the car's interior and died from the resulting head injuries. The other occupants of the car escaped fatal injury thanks to their seat belts, which prevented them from hitting any object of the car's interior, even though their bodies were compressed by the seat belts at the impact of the collision. Rear-seat passengers did not harm front-seat passenger, either.


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Institute for Traffic Accident Research and Data Analysis (ITARDA)