Near Largo, Maryland
February 1, 2002
Disclaimer: Simulations presented below used scene surveys, vehicle testing, and vehicle operating characteristics. The depictions do not represent actual lighting conditions at the time of the accident.
Videos were presented at the Board meeting on June 3, 2003 in Washington, D.C., for the Largo, MD Accident Investigation.
Vehicle Dynamics: This accident involved a Ford Explorer, that veered off the left side of the roadway, crossed over the median, climbed up a guardrail, flipped over, and landed on top of another vehicle traveling in the opposite direction. At the time of the accident, high crosswinds were present and the driver was engaged in a handheld wireless telephone conversation. The Safety Board evaluated the Explorer's controllability in crosswinds and the potential effects of a driver-delayed reaction time due to wireless telephone use. In the simulations an Explorer traveling approximately 70 mph was subjected to wind gusts similar to those measured at nearby Andrews AFB near the time of the accident. The duration of the gust was varied in the simulations because the duration of the wind gusts was uncertain. The following simulations illustrate some of the results of the study. The simulations shown here were designed to test aspects of the behavior of the Explorer in high gusty winds and do not recreate the accident.
Largo Vehicle Dynamics 1 (Video = 1,398K) This video shows the results of the simulation of an alert driver subject to a 23 mph sustained wind and a 44 mph wind gust coming from the driver's left front. Shortly after the video begins the Explorer is subjected to a 44 mph wind gust lasting for 2 seconds. The tiremarks on the roadway indicate the path of the accident vehicle across the center median. Note in the video that the gust pushes the Explorer in the opposite direction of the tiremarks and that control is maintained throughout the simulation.
Largo Vehicle Dynamics 2 (Video = 1,263K) In this video the Explorer is subjected to thesame wind conditions as in the previous video; however, the driver reaction time has been increased to take into account the delay caused by the distraction of talking on the wireless telephone. Despite the increase in reaction time the Explorer remained controllable throughout the simulation. Note in this simulation that the right side tires of the Explorer cross completely into the next lane to the right where they did not when the alert driver reaction range was used in the simulations. (Full Speed)
Largo Vehicle Dynamics 3 (Video = 653K)This video shows a frontal side-by-side comparisonof the two simulations shown in the previous videos. The distracted driver is shown on the left side of the screen while the alert driver is shown on the right. As you can see in the video the distracted driver deviates more from the intended path then the alert driver does. (Full Speed)
The simulations were produced on an HVE™ system using SIMON™ and EDGEN™ programs. All of the programs are trademarks of the Engineering Dynamics Corporation.