Using EDR data to explain Sudden Unintended Acceleration (SUA) events
By Iwan Parry, TRL Principal Consultant
Many of us will remember where we were on the 31st of August 1997. I was in Sydney, Australia, working as a consultant in collision investigation, when I heard the news that Princess Diana had died following a tragic collision. The next day I witnessed the huge media interest and need for answers as our company responded to call after call from newspapers and TV news requesting comments and opinion on the meagre evidence available at the time.
More than six years later, in January 2004, the UK’s inquest opened into the death of Diana, Princess of Wales and Dodi Al Fayed. The Metropolitan Police were immediately tasked to open their own investigation, to look at the events of that night and to provide a detailed forensic investigation of the collision, the sequence of vehicle movements leading to it and the condition of the vehicle itself.
At this stage I was leading the Collision Investigation team at TRL. Soon after the Met team were established, we were contacted by the Metropolitan Police’s lead investigator to discuss the assistance that TRL could offer the investigation. These discussions led to one of the most in-depth and innovative collision investigations of its time.
Having developed applications for new technologies in collision investigation, particularly 3D laser scanning, collision simulation and 3D visualisation, and having introduced these methods to the UK courts for the first time during this period; my team and I at TRL were able to offer expertise in both conventional collision investigation and new cutting-edge methods.
Applying these methods, we laser scanned the collision site in Paris, created the complex 3D road geometry of the approach to the Alma Tunnel and simulated the motion of the Mercedes. This approach was underpinned by extensive validation of the simulation model with a duplicate Mercedes S280 on TRL’s test track in Berkshire. This simulation enabled detailed analysis of the Mercedes’s movements as it approached and entered the tunnel, its loss of control whilst avoiding a vehicle near the tunnel entrance, the driver’s response and the ultimate collision with the 13th unprotected central pillar from the eastern entrance.
This pioneering approach, marrying 3D laser scanning with validated 3D simulation, provided powerful results, which enhanced the findings of the original French investigation and verified the outcomes of our traditional reconstruction methods, such as those used to determine vehicle speed and the path to the point of impact.
TRL’s innovation with laser scanning, simulation and visualisation over this period led to significant advances in the use of laser scanning in collision investigation and its use is commonplace today. Laser scanning now enabling faster and more comprehensive scene surveys, it is enhancing CCTV analysis, and is creating 3D vehicle and scene models for driver visibility assessments, incident visualisation and in-depth simulation analysis.
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