A fatal vehicle fire in Fort Lauderdale Florida is reminiscent of the fire death of Paul Walker from the “Fast & The Furious” But it also illuminates some confusing issues.
Two young men Barrett Riley and Edgar Monserratt died in the crash. A third male occupant, Alexander Berry, was reportedly ejected from the vehicle and survived. A lawsuit, filed on October 8, 2019, by Riley’s father claimed that his son did not die from the collision but from the fire that engulfed the vehicle after the collision. The culpert in the fire was claimed to be the Telsa’s battery.
Part of the confusion surrounding the case involved the reporting that the U.S. National Transportation Safety Board (NTSB) concluded that the Tesla was being driven at a speed of “116 mph before the fiery crash”. And this finding was broadcast in large print across some local newspapers. A spokesperson for Tesla claimed “unfortunately, no car could have withstood a high-speed crash of this kind”. Then, when you read the fine details the facts turn out to be substantially different.
In a local news article (Sun Sentinel) the NTSB conclusions were that “Three seconds before impact the car was travelling at 116 mph. It slowed to 108 mph as the driver applied the brakes, and then decreased to 86 mph, according to data from the car”.
Witnesses observed that the Telsa struck a wall twice at 1313 Seabreeze Blvd, and it burst into flames after the second impact. The Tesla then continued south across the boulevard where it hit a metal light pole and stopped in a driveway. The distance between the second impact and the vehicle’s rest position was estimated at about 200 feet (61 metres). Witnesses could not put out the blaze nor could they extricate the two persons inside.
These circumstances are not much different than a widely publicized collision six years ago, on November 30, 2013, when a Porsche Carrera GT crashed on Hercules Street in Santa Clarita California, on the northern outskirts of Los Angeles. That collision caused the death of its right front passenger, Paul Walker, who was famous for his movie role in the “Fast and the Furious”. The driver of the Porsche, Roger Rodas, was travelling around a right curve of the suburban road when he lost control and the vehicle commenced a clockwise yaw, proceeding off the right roadside where the vehicle struck a tree and burst into flames.
With respect to the Walker crash I was contacted a few years ago by an unknown entity who, at first, asked me some general questions about the incident. Afterward came further and more detailed e-mails and reports, further questions and further analysis. As such general discussions often lead to a retainment by a client I did not think much of it buy the extent of subsequent contacts led to much more than general discussion. I will not discuss these details further other than to say that I conducted substantial analysis of the Paul Walker collision. Below is a general photo of the site with the words “Direction of travel” and “Crash Site” written on it.
The photo below shows the area of the site as the Porsche was already rotating clockwise and travelling toward the right curb and into the trees in the background.
The photo below shows another view of the yaw marks s the Porsche impacted the curb and then struck the tree which shows evidence of fresh contact.
The photo below shows the Porsche fully engulfed in flames while positioned against a second tree, not too distant from where it struck the curb.
In the aftermath one can see that there appears to be considerable destruction leading to the untrained conclusion that the Porsche must have been travelling at tremendous speed.
One of the conclusions from the police investigation was that the tires on the Porsche were over nine years old. Although data from an airbag control module was interrogated no actual, pre-impact speed data was available.
Without this event data investigators used what evidence was available from the geometry of the yaw marks to calculate a “critical Speed”. That speed was in the range of 90 mph. Five problems arose from this analysis. Firstly the investigators did not consider the fact that, as the Porsche was travelling through the curve its tires travelled over some “Botts Dots” or circular, elevated markers that were installed between the lanes so as to guide drivers around the curve. Secondly they used unacceptably high coefficients in their speed calculations. Thirdly they did not consider whether tires that were “over nine years old” could generate such high values of friction. Fourth, they did not acknowledge that, because of the advanced angle of rotation at the point where the first usable yaw marks were available, the speed calculation would be unstable and a critical speed calculation is generally not advised by the collision reconstruction community under such circumstances. Finally they did not conduct an independent energy analysis to confirm if the calculated speed matched with the pre-yaw, kinetic energy possessed by the Porsche. In other words, if the Porsche was truly travelling at 90 mph it must have possessed a very large amount of kinetic energy that would have to be dissipated (transferred or “removed”) in order to come to halt. Energy would be dissipated through the visible yaw marks, striking the curb, striking the trees and through production of the crush and deformation that was visible in the structure of the vehicle. Despite these problems in the analysis the news media, and the public took the police conclusions to be correct.
Returning to the Fort Lauderdale collision, a getter set of objective data was available because of the imaging of the event data recorder in the Telsa. Still, the idea was planted in the public’s understanding that, because the Telsa was travelling so quickly there could be no other conclusion reached except that the collision events were far too extreme for anyone to argue that the collision could have been survived except to the fire that erupted.
I do not have the details from the investigation of the Fort Lauderdale crash like I did in the Walker case. However any reconstructionist worth his or her salt would examine the Fort Lauderdale crash and recognize that the process of the dissipation of the vehicle’s kinetic energy should be evaluated. Much like the accounting term “follow the money trail”, so it is in the collision reconstruction that we “follow the energy trail”. In other words, we look at the full length and time of destruction to consider if any of the individual parts could be termed life-threatening.
The NTSB report indicated that the Tesla was travelling about 86 mph when the initial impact occurred but this does not mean that the total speed and kinetic energy was dissipated in a single impact. Indeed the evidence indicates that, after striking the wall on the first impact, the Telsa crossed a driveway and struck the wall a second time on the opposite side of the driveway. Furthermore, the Tesla then travelled about 200 feet (61 metres) and then crashed into a lamp post on the opposite side of the road. Thus we have at least four separate decelerations that were combined to result in the 86 mph speed loss. Even in the travel distance of 200 feet the Tesla could easily have lost 50 mph, thus were would not be much speed loss left over to suggest that either of the wall impacts were non-survivable. This is further confirmed by the fact that a rear passenger in the Tesla was ejected and survived. These facts, much like in the Paul Walker collision, demonstrate how facts mentioned in the wrong context, and coming from poor analysis, can result in erroneous conclusions.
There are many collisions occurring daily that result in vehicle fires and some of them are deadly. Some of them are deadly because it was the fire that killed the occupants. It is important not to be swayed by appearances and to look carefully at the facts before concluding that a vehicle fire was not preventable. Even a Tesla travelling at 116 mph may be involved in several impacts, each of limited severity, that occur over a long distance and over a long time, resulting in relatively minor impact severities that should not result in a fire. Think about the analogy of a commercial jetliner that is travelling at 750 mph but is able to come to stop safely because it does so over a long time and distance. One must separate those collisions where a change-in-velocity occurs very quickly and therefore can cause major injury and death, from those collisions involving an identical initial velocity but their change-in-velocity occurs gradually both in time and distance.
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