Hiromu Naruse Lexus LFA accident

Sadly, a Lexus LFA was involed in a crash along with a BMW, which ended the life of Toyota's chief test driver Hiromu Naruse. According to my favorite website Autoblog, the Lexus LFA collided with a BMW that was also a test vehicle. The BMW had two occupants, of which one is in critical condition and the other reported as survived. This is terribly unfortunate event, and makes me wonder about the physics behind the crash. Amazingly, the LFA is reasonably comparable the the 3 Series in many ways but yet very different at the same time. It's these differences such as weight, layout, and structural design that determine the outcome of an accident. Below, I will respectfully discuss the aspects that I find important to the conclusion of the accident.

The BMW 3 Series weighs 3,362 pounds without any passengers. Add two occupants and this brings the total to a minimum of 3,662 pounds. The Lexus LFA weigs 3,263 pounds without passengers, and with one occupant would weigh a minimum of 3,413 pounds. The weight is comparable, but when accident occurs that difference counts. Due to occupant weight, the BMW is already at a strong advantage against the LFA. *See impact force table below!

More than just weight, let's look at the vehicles involved. The engine of the Lexus is a 4.8 liter V10, while the 3 Series totes a small 3.0 liter inline six cylinder. The difference is that the LFA has a mid-front engine and RWD layout, while the 3 Series is a front engine layout with RWD. The mid-front engine layout is ideal for handling and the driving experience, but in a wreck it can be hazardous as the space between this heavy component and occupants is less than that of a front engine layout. This aspect of the accident is totally in favor of the BMW.

The structural design and attributes of each vehicle are all put to test during an accident of this magnitude. The BMW is designed for a luxurious ride that has a sporty feel, while the Lexus LFA is designed to be a street legal race car. The BMW is outfitted with heavier components in nearly every aspect of the vehicle. Thicker everything, from carpet to wiring. The LFA, in all of it's glory is an amazing sports car and quite possibly the best car to ever grace the pavement; but it's designed for speed and driving experience because it's an ultra rare exotic supercar. The BMW is very nice, but in Europe and other countries they are used as taxis, police vehicles, and wagons may be used as ambulances. When considering structural evaluation, the BMW is a clear winner. Race cars and luxury sedans simply do not mix.
Small details 
More than the standard evaluation points, it's the small details that really matter. The BMW 3 Series shown in the accident came with the Star Spoke 199 wheel, a $4,800 option. This is a very well built wheel, and it's clearly scene in the wreck footage that the integrity wasn't even compromised. The Lexus wheel on the other hand was the same. Even though the wheel doesn't seem to be that great of a comparison point, consider the collision point and the energy around that area of the vehicle.

A quick impact force calculator shows a vehicle that weighs only 3,200 pounds stopped within 3 feet generates a force of 64 tons! Who knows how fast these two vehicles were traveling upon collision, both are highly capable of speeds well beyond a measly 60 miles per hour. Here's a quick estimate of Speed vs Impact force for 3,200 pound vehicle, stopped within 3 feet:
30 mph = 16 tons
60 mph = 64 tons
120 mph = 256 tons
150 mph = 401 tons
200 mph = 713 tons

The results above were figured out using rudimentary impact collision calculator and may not be accurate to this specific situation. No matter how we look at it, the evaluation of the wreck is clearly in the BMW's favor. This doesn't mean that the LFA is a bad or unsafe vehicle, it's just a real life example of physics. Nothing about the wreck was in favor of the LFA.Rest in peaceHiromu Naruse, your contribution to the automotive world will never be forgotten. The LFA is a beautiful vehicle, and through it your name will live on.

Video content: Lexus LFA crash

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Source: Tampa Sports Car Examiner

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