Cerca nel blog


Fatal Tesla crash in Switzerland: a local report

by Paolo Attivissimo. An Italian version of this article is available here. Una versione in italiano di questo articolo è disponibile qui.

A 48-year-old German driver died in the crash of his Tesla Model S on the A2/E35 highway in Canton Ticino, Switzerland, on May 10. Rescuers were unable to extract the driver and the car was completely destroyed by the fire that followed the accident. The crash has attracted considerable media attention locally and raised concerns about the safety of electric cars in general and Teslas in particular.

I share those concerns on a very personal level, as I own an electric car (not a Tesla, but a much more modest Peugeot iOn). More importantly, I live close to the accident site and travel often on that same stretch of highway.

The basic facts

The accident occurred at this location on the A2/E35 highway near Monte Ceneri, on the northbound roadway (I’m using US English terms) around 3:30 pm local time. No other cars were involved.

This is an annotated Google Maps screenshot of the area: north is up and the northbound roadway is the lower part of the highway, with northbound traffic traveling left to right. The two-way road below is the state road (strada cantonale), which is not involved.

The crash site is just after a tunnel (bottom left in the screenshot above), where road work is currently being carried out and therefore northbound traffic is split: the left (overtaking) lane is diverted onto the southbound roadway, while the right lane stays on the northbound roadway.

I took this video today, traveling exactly along the same route and lane used by the Tesla driver. I traveled at exactly 78 km/h (21.6 m/s), using cruise control to maintain speed. The local speed limit is 80 km/h (about 50 mph). The camera was fixed to my windscreen and was not operated by me. Road signs and barrier placement may have been changed slightly since the day of the accident. There are no large impact marks on the guardrails and there are few signs of skid marks.

Quick timeline and distance references:

  • 0:08 First road sign (on the right) warning of lane change ahead.
  • 0:30 Second road sign (on the right) warning of lane change; 80 km/h (50 mph) speed limit overhead (it’s a reminder; speed limit is already 80 km/h before entering the tunnel). Notice how many drivers are disregarding the speed limit.
  • 0:41 Twin speed limit signs at roadside (left and right).
  • 0:51 Speed limit sign at tunnel exit.
  • 0:57 Road divides with an S-turn. Notice yellow chevrons placed by police survey agents after the crash. Distance from tunnel exit is about 150 meters (6 seconds at 78 km/h).
  • 1:01 Road straightens.
  • 1:04 Fresh tarmac, diagonal white lines on the right lane and missing green markers on right guardrail suggest that this is where the car came to a stop and burned. This location is about 160 meters from where the road divides.
  • 1:35 Diagonal burn mark on lane, possibly unrelated to accident, since it is 820 meters from tunnel exit (38 seconds at 78 km/h). The car may have been moved here.

According to the initial police report published in local media (Tio.ch), the car overturned and was traveling south. However, photographs of the car on fire clearly show its B-pillar (the vertical part of the car body between the front and rear doors) standing upright and indicate that the location of the accident was a northbound lane.

Other photographs, provided to me confidentially, show that the car clearly was not overturned in the initial stage of the fire and that its rear end was turned in the direction of travel. It would appear that the initial police report is incorrect regarding the overturning and the southbound travel.

One eyewitness reported confidentially that the car was traveling above the local speed limit, hit the lane divider and went into a spin, splitting at the front.

Credit: Tio.ch/Rescue Media. Travel direction is to the right.
Credit: Tio.ch reader. Travel direction is to the right.

Was the Tesla on Autopilot?

Currently it is not known whether the car’s driver assistance feature known as Autopilot was active or not.

At first glance, the circumstances of the crash (road works with possibly confusing surface markings, excellent visibility and weather) would seem to suggest a crash induced by excessive reliance on Autopilot’s lane-following functions. However, when I drove through that very narrow S-curve with my car (much smaller than a Tesla Model S) at just below the speed limit I found that it required careful handling, as you can see in the video, even though the S-curve had been made less sharp after the accident, so perhaps the crash may have just been caused by the excessive speed at which the Tesla (a much wider car) was reportedly being driven.

Therefore, it is unwise, at this point, to blame Autopilot or the driver. In view of the loss of life, I believe that the matter should be treated with caution and respect.

It should be stressed that the driver is required to be vigilant at all times during Autopilot use, as stated repeatedly in the car’s manual and on the car’s display every time Autopilot is enabled.

Why the raging fire?

Media attention has focused on the unusual intensity of the fire. As reported by Ticinonews, the Fire Brigade of Bellinzona stated that “the violent impact of the lithium ion batteries probably caused a phenomenon known as thermal runaway, i.e., a rapid and unstoppable increase in temperature”.

This is a well-known characteristic of all electric cars: for example, during the filming of The Grand Tour, Richard Hammond’s notorious accident in a Rimac Concept One triggered a catastrophic fire.

This is clearly a concern to all electric car owners, such as myself. However, it should be noted that petrol cars, too, can burn very dramatically: they are, after all, carrying a substantial amount of highly flammable fuel in a tank. Some petrol car makers have been forced to issue recalls due to the risk of fire (for example Lamborghini). Here are a few examples of non-electric car fires.

Not an electric car (Lamborghini).

Also not an electric car (McLaren).

A petrol car.

Another petrol car.

Recently, on May 8, 2018, a Mercedes Citaro bus burned to destruction, as reported by Repubblica:

In other words, any engine-driven vehicle can catch fire. While battery fires tend to be more intense and harder to extinguish than fuel-related fires, the risk of a raging blaze is always present, regardless of the power source. That is why many countries require or recommend having a fire extinguisher on board. All drivers, not just electric drivers, should bear this in mind.

Trapped inside by Tesla’s automatic doors?

This Swiss accident, with its fatal outcome, has prompted another concern, which specifically involves Teslas: the Model S has retractable door handles and a complex power-driven door opening system. Did this system hinder any attempts to extract the driver?

Tesla claims that Model S door handles are extended automatically if an event triggers airbag inflation, as explained in the Model S Emergency Response Guide, page 23: “When an airbag inflates, Model S unlocks all doors, unlocks the trunk, and extends all door handles”.

A crash-tested Model S presents its door handles.

However, this is not always true, at least according to these crash tests (for example at 2:30 and 2:54):

Rear doors also have a mechanical release cable located just below the rear seats. All Tesla drivers should get acquainted with these emergency procedures, and there are specific guides for firefighters and first responders.

These emergency mechanisms, however, can only function if the doors are not too damaged and distorted to open.

It is unclear at present why the driver in this Swiss accident was not extracted from the car.

So now what? Mitigation strategies

Understandably, many electric car drivers are shaken by this accident, and so are many people who are considering a switch to an electric car. It seems there is at least one bitter lesson to be learned: whether electric or fuel-driven, we are all riding on highly flammable vehicles, which despite the best efforts of safety designers will fail if they are subjected to sufficiently catastrophic impacts. That is something we all tend to push to the back of our minds.

We should treat our cars with more respect for their limitations and perhaps consider a few simple precautions to reduce the risk of finding ourselves in a catastrophic situation: lower speeds, greater attentiveness, emergency training, a fire extinguisher, and a belt-cutter/window-breaker tool, just in case professional rescuers aren’t immediately available.

Rescue should always be left to professionals, of course, but in an emergency it may be useful to know some basic procedures, such as the ones presented in these videos. Be safe.

Sources: Incendio sul Ceneri: "Ecco perché è stato così violento", Ticinonews; Tesla collabora con la polizia ticinese, Tio.ch; Auto in fiamme sul Ceneri, morto il conducente, Tio.ch; Rogo A2, batterie in causa, Rsi.ch; "Ecco perché ha preso fuoco velocemente", Gdp.ch; Un sorpasso azzardato, poi lo schianto, Tio.ch.

Nessun commento: