Case Study - 4x4 Rollover & Ejection

The case study below shows how Advanced Simtech used computer simulation to assist the police in identifying the driver of a stolen vehicle following a fatal collision.

Initial investigations deduced that the surviving occupant had been driving the vehicle at the time of the crash, however, he denied this to be the case.  Available forensic evidence was inconclusive and so Advanced Simtech were asked to reconstruct and simulate the incident using our specialized software and methodologies.

Physical evidence collected from the scene was used in conjunction with vehicle specification and tyre-characteristic data in order to build a detailed computer model.

Using the iterative methodologies developed internally at Advanced Simtech we were able to consider a wide range of scenarios and to show that, contrary to expectation, in each case it was the driver and not the passenger who was ejected from the vehicle.

Case Study:   4 x 4 Rollover & Ejection  

Customer: Devon & Cornwall Police 

 

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Case Overview

Two occupants were travelling in a stolen short wheelbase 4x4 vehicle 

  • The driver lost control on the approach to a T-Junction, resulting in the vehicle colliding with a petrol station forecourt crash-barrier and rolling over before coming to rest on its passenger side.
  • One occupant was found partially ejected through the passenger-side window, trapped between the vehicle and the road. His injuries were fairly minor, but he had suffocated under the weight of the vehicle being exerted onto his chest by the A-Pillar (Frontal vertical roof support).
  • The other occupant was unharmed and stated that he was not driving the vehicle at the time of the incident. This could not be proved or disproved forensically.

Objective

To reconstruct the collision and ascertain the validity of the statement made by the surviving occupant. 

Solution/Methodology 

  • Using MADYMO we were able to recreate the loss of control and collision sequence that lead to the fatality.
  • The calculated vehicle motion was then used to predict how each of the two occupants would have moved around the occupant space.
  • In order to explore the scenario fully, it was necessary to investigate a range of seating positions for both driver and passenger.
  • In order to give more detail to the analysis we were able to utilise the MADYMO Human Body Models (HBMs) which offer a substantial increase in the biofidelity of their responses to the forces of motion in comparison to the previous approach of using an anthropometric crash test dummy model.

Results

Our evidence clearly demonstrated that the survivor’s statement was truthful, and that in this situation even given the limited space, the driver would be the ejected occupant.

In terms of the simulation, the driver was consistently ejected except where the passenger was given an initial seating position that was significantly further forward, thus blocking the window aperture. In all scenarios there was no tendency for the passenger to eject.

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Conclusion/Outcome

Based on our work, the charges against the surviving occupant were dropped. The computer simulation was used in the Coroner's court to demonstrate how the fatality occurred.

With ever increasing applications, specialized software and highly advanced methodologies; contact Advanced Simtech today to find out how we could benefit your organization.