A fatal scooter accident

This case relates to a motorized scooter accident. Scooters can be gas or electric powered and can reach speeds of 20 mph.  Unfortunately they often compete with cars for the roadway and they always lose.

In this case, a young man on his scooter was sideswiped by V #1 and then struck by V#2.  He died of massive head injuries.  The question was, what caused his death?

The possibilities were:

1)       head contact with the ground
2)       head contact with the scooter
3)       head contact with vehicle #1
4)       head contact with vehicle #2

The task was to discern which caused his death.  First came an evaluation of the autopsy.  The report stated that he died of blunt traumatic injuries to the head.  Specific head injuries were noted.  It was also noted that there was an absence of any major injury to the neck, abdomen, thorax or extremities.  Now it was time to evaluate the four possibilities.

Head-to-ground contact due to falling

Significant force can be produced in a simple fall to the ground (a hard surface).  It is important to understand, however, that the magnitude of the force from a fall is dependent on the height of the fall and independent of horizontal velocity.  In his case, his maximum fall height was 64 inches.  Calculation of the approximate force produced by an unbroken free fall from a height of 64 inches (an absolute “worst case” scenario), demonstrated that such a fall could not result in a head contact force of sufficient magnitude to produce the observed skull fracture and the underlying brain injury in this case even under the “worst case” fall scenario.  Further, the skull fracture patterns observed were absolutely inconsistent with a fall to the ground, which was a flat surface.  His head injuries were not the result of a fall to the pavement.

Head contact with the scooter

Significant force producing contact between the decedent’s head and the scooter which he was riding was not a supportable possibility.  They were traveling in the same direction and at the same speed.  Further, the scooter represented a minor mass structure.  The application of basic Newtonian physics precluded the scooter as the source of his head injury.

Head contact with Vehicle #1

There was no evidence to support the notion of significant head contact with V. #1.  Statements by witnesses indicated that the decedent was upright during his passing interaction with V. #1.  Further, it was noted that he was 61 inches tall and standing on the scooter platform (+3 inches), this would place the impact point on his head at approximately 60 inches above the ground.  The roof line of V. #1 was 56 inches above the ground or 4 inches lower than the strike point on his head. Finally, the contact evidence on V. #1 was on the rear quarter panel at a height of less than 26 inches above the ground.  Therefore his head injuries were not the result of contact with V. #1.
Head Contact with Vehicle #2
Contact between the decedent’s head and V. #2 represented the only possible source of the head trauma that was noted in the autopsy.  It was noted that V. #2 was traveling at approximately 28-30 mph at the instant of impact.  Further, the bumper as well as numerous undercarriage structures on V. #2 presented the required stiff structures that produced the linear depressed skull fractures observed during the autopsy.  V. #2 represented the only viable source of energy and structure for generating the massive head trauma experienced by the decedent.