July 15, 2003
Henrietta, Texas May 8, 2001
and Randleman, North Carolina July 1, 2001
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.
Videos were presented at the Board meeting on July 15, 2003 in Washington, D.C. for the Henrietta, TX Accident Investigation.
Vehicle Dynamics: This study examined an accident involving a 15-passenger van, which, after suffering a left rear tire failure, entered the center median and rolled before coming to rest upright. The primary goals of this study were 1) to gain a better understanding of the driver's actions prior to leaving the roadway and 2) to obtain crash pulse estimates in circumstances similar to this accident to aid in subsequent occupant motion studies.
HenVehDyn1.wmv (Video = 873K)
This view shows a chase view of the van. The initial speed of the van in the simulation is 67mph. The results of the simulations indicated that the van rolled two or more times before coming to rest. In this particular simulation the van rolls twice. (Full Speed)
HenVehDyn2.wmv (Video = 1237K)
This view shows the driver's potential view for the same simulation. The arrow at the bottom middle of the screen indicates the direction of the driver's steer inputs. (Full Speed)
HenVehDyn3.wmv (Video = 1224K)
This view shows a stationary frontal view of the same simulation. (Full Speed)
The simulations were produced on an HVE™ system using EDVSM™ and EDGEN™ programs. All of the programs are trademarks of the Engineering Dynamics Corporation.
Occupant Kinematics: This study examined the occupant kinematics during the rollover of a 15-passenger van. The main focus of the investigation was to determine possible kinematics that led to ejection, the time period of the potential ejections, and to determine injury causing kinematics or impacts. The time during which the ejections occurred was used to determine whether all the ejections could have occurred during the first overturn or if at least two overturns were necessary. The occupants were simulated in the restraint condition similar to the accident, all restrained in lap belts, and all restrained in lap/shoulder belts. The results of the simulation indicated that predicted injury levels were reduced and full ejection was eliminated when occupants were properly restrained with lap/shoulder belts. The simulation did not account for intrusion when determining injury.
HenOccDyn1.wmv (Video = 1289K)
This view displays the kinematics of the simulated occupants in the passenger compartment of the 15-passenger van looking rearward during the full overturn sequence. The driver and front seat passenger were not simulated. The occupants are shown in the actual restraint condition representing the use of restraints in the actual accident. (The occupant in the third row right side of the van was restrained by a lap belt while all other occupants were unrestrained.) (1/3rd Speed)
HenOccDyn2.wmv (Video = 1203K)
This view shows the simulated occupants restrained with lap belts only during the first overturn only. (1/3rd Speed)
HenOccDyn3.wmv (Video = 1216K)
This view shows the simulated occupants restrained with lap/shoulder belts during the first overturn only. (1/3rd Speed)
The simulations were developed using GATB™ and were produced in Adobe Premiere™. The programs are trademarks of the Collision Engineering Associates and Adobe Systems Incorporated, respectively.
Tire Blowout Testing: This testing explored the effects of a tire tread separation and blowout on the handling of a 15-passenger van. The van was loaded similar to the Henrietta accident van and had similar tire pressures.
dc_tire.mpg (Video = 4951K)
This view shows a chase view of the van. The initial speed of the van was approximately 75 mph. The results of the test show that the van did not stay in its lane of travel after the blowout, initially veering left until the driver countered by steering to the right. The driver stated that the key issue was not to oversteer since any steering input was magnified.