Accident Investigation Simulations

Highway Accident Report:
Crash of 15-Passenger Van in a Bridge Abutment
Memphis, Tennessee
April 4, 2002

Videos are available in wmv format, and were presented at the Board meeting on April 7, 2004 in Washington, D.C. for the Memphis, TN Accident Investigation.

Disclaimer: Simulations presented below were developed based upon scene and vehicle surveys, passenger statements, vehicle operating characteristics, and pictures from the scene. The depictions represent actual lighting and weather conditions at the time of the accident.

Vehicle Dynamics: This study was conducted to determine the vehicle dynamics of a 15-passenger van during this accident sequence. The van exited the roadway and overrode the guardrail end treatment, then traveled on the grass behind the guardrail and subsequently impacted a series of guardrail posts, a light pole, and a bridge abutment. The van's speed at departure from the roadway was approximately 63 mph. The maximum resultant acceleration during the initial impacts with the guardrail posts and the light pole was approximately 12.4 g. The maximum resultant acceleration during impact with the bridge abutment was 31.1 g.

  VehDyn1.wmv (Video = 513KB)

The first view is from the bridge looking down at the accident sequence. Notice the curvature of the roadway. The van was initially in the left lane and drifted, without driver action, for more than 4 seconds before leaving the roadway. (Full Speed)

 

  VehDyn2.wmv (Video = 700KB)

The second view follows the van from the left side throughout the accident sequence. Notice, in this video, the van's departure from the left lane, the impact with the guardrail end treatment, impact with the light pole and guardrail posts, and finally the impact with the bridge abutment. (Full Speed)

 

  VehDyn3.wmv (Video = 474KB)

The third view shows the motion of the van from behind. (Full Speed)

 

  VehDyn4.wmv (Video = 422KB)

The final view focuses on the van motion from a position in front of the van. (Full Speed)

 

The simulations were produced on an HVE™ system using EDSMAC4™, SIMON™, and EDCRASH™ programs. All of the programs are trademarks of the Engineering Dynamics Corporation.

Occupant Kinematics: This study examined the occupant kinematics during the crash of a 15-passenger van. The main focus of the investigation was to determine possible kinematics that led to occupant injury and ejection, to determine injury causing kinematics or impacts, and to investigate a variety of alternative restraint conditions. Only one passenger, in the right front seat, was restrained. Based on the ages and the passenger sizes, several of the passengers should have been restrained in booster seats in order to provide proper belt positioning on the body. Other passengers could have been properly restrained with the available lap/shoulder belts or lap belts. Simulations were conducted to determine the occupant kinematics during the collision. The occupants were first simulated in the restraint condition similar to the accident scenario. The occupants were then restrained with the available restraints on the van, either lap belts or lap/shoulder belts depending on the seating position. Finally, occupants in the first row bench seat were restrained with the available restraints or in boosters seats where appropriate by age. The results of the simulations indicated injuries in both the actual and the available restraint conditions. Injury levels were reduced for the two occupants simulated in booster seats.

  OccKin1.wmv (Video = 778KB)

This view displays the kinematics of the simulated occupants in the 15-passenger van during the impact sequence. The occupants are shown in the actual restraint condition representing the use of restraints in the actual accident. (A lap/shoulder belt restrained the occupant in the front passenger seat while all other occupants were unrestrained.) (1/10th Speed)

 

  OccKin2.wmv (Video = 786KB)

This view shows the simulated occupants in the available restraint condition, that is, restrained with lap/shoulder belts at the outboard positions and lap belts at the center positions. (1/10th Speed)

 

  OccKin3.wmv (Video = 791KB)

The view shows a comparison between the actual and available restraint condition from an overhead view. (1/10th Speed)

 

  OccKin4.wmv (Video = 773KB)

This view shows the simulated occupants in the first row bench seat with the 6-year-old and 8-year-old restrained in high backed booster seats. The 10-year-old is restrained with the available lap/shoulder belt. (1/10th Speed)

 

The simulations were developed using MADYMO™ and were produced in Adobe Premiere™. The programs are trademarks of TNO Automotive and Adobe Systems Incorporated, respectively.

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