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Electric Automobiles Safety

Electric Automobiles Safety
« on: 03 September , 2019, 14:05:08 pm »
Hello partners,

Today I wanted to bring a topic quite important for the automotive industry. The safety of the automobiles, more precisely the safety of the electric vehicles. For the last couple of years there has been a tremendous debate on whether an EV is more dangerous in an accident than a diesel or gasoline car. Therefore, I am going to explain the whole situation.

Due to the very own build of an electric car, some of its parts could represent a serious hazard for the life of the occupants of the vehicle. I am referring to the battery. As we have said previously on the blog, the main component of the batteries which electric vehicles use is lithium. In a car crash with an electric automobile involved, the battery could receive severe damage, which may lead to an explosion.

Fortunately, such a dangerous scenario has been carefully thought by the automakers. Car manufacturers build a triple-layer titanium envelop around the battery, which works as a shield, preventing the precious component from being damaged.

Even if the risk of a battery explosion is highly improbable, that risk is still there. However, although the battery may now seem like a little jeopardy for the sake of the occupants of the vehicle, it is indeed the reason why electric cars are safer than combustion engine ones.

This reason is simple. Battery packs are the heaviest component of the vehicle, and they are always positioned underneath the floor of the car. Therefore, as the battery weight pulls the entire automobile down, it also lowers the center of gravity. In practical terms this means that the car is unlikely to suffer a tipping or rollover, because the lower the center of gravity of a body the harder it is to overturn it.
 
The strategic location of the battery along with some top of the line engineering, provide electric cars with the safest environment in the industry right now. But this is not something which I say. It has also been declared by the competent institutions regarding vehicles safety. As you may know, before cars are launched to the market, they must pass several safety assessments. In the United States of America, the organization which carries out these tests is National Highway Traffic Safety Administration (NHTSA) and in Europe, this task is done by the European New Car Assessment Programme (Euro-NCAP). Both institutions have awarded their maximum grades to several electric vehicles. As matter of fact, their rankings of safest automobiles are led in both cases by the Tesla Model 3, and recently, the Audi e-tron has also obtained a magnificent score in all the safety tests. I leave you the links to the webpages of the NHTSA and the Euro-NCAP.

https://www.nhtsa.gov/

https://www.euroncap.com/en

To sum up I wanted to conclude saying that as we research about electric vehicles, we find more and more advantages as well as reasons to be sure that mobility is following the right way towards the upcoming future.

Best regards,
Pablo García

Re: Electric Automobiles Safety
« Reply #1 on: 07 September , 2019, 20:34:39 pm »
Hi Pablo,

Firstly, I would like to congratulate you for coming up with this new topic. I think few people, and I must exclude myself of them, do actually think as security as a main aspect to take into account when choosing a vehicle. However, it is true that it ought to be the most (or one of the most important) features in a vehicle.

However, one must remember a concept of Economy called "opportunity cost": that means, each time we take a decision, we have to "pay" with the opportunity of choosing another one and its benefits. For instance, electric vehicles create another problem, since not only are safer, but more silent, because they do not burn fuel . And although less noise is supposed to be less polluting and more benefitial, it is also dangerous since pedestrians have more difficulties to realize when an electric vehicle is coming, increasing the probability of accidents happening. This is why European Union has made compulsory for electric vehicles to emit sound (with a system called AVAS), but this is still not compulsory worldwide. Moreover, there are some critics to this system, since they are thing it has the "opportunity cost" of reducing acustic pollution, which is becoming a great problem.

https://edition.cnn.com/2019/07/01/business/electric-vehicles-warning-noises-scli-intl-gbr/index.html#targetText=The%20sound%2C%20produced%20by%20an,disable%20it%20if%20they%20want.&targetText=From%20July%202021%2C%20the%20regulation,vehicles%20registered%20in%20the%20bloc.

So, what decision should be taken for electric vehicles to be "safer"?

Regards,
José Javier (Veteran)


Re: Electric Automobiles Safety
« Reply #2 on: 08 September , 2019, 16:15:23 pm »
Hello José Javier,

I am aware of the new policy implemented by the European Union which compels automakers to install a noise-making device in their vehicles in order to prevent any accidents with pedestrians involved. In fact, I posted this information on the news section of the forum. There, I exposed my opinion about this topic. Nevertheless, as you have reopened this matter, I think it is time to expand my point of view giving some more data which may help us all to have a bigger perspective of this issue.

The electric mobility revolution is not only a change in the way we move. As we transition towards a zero emissions future, electric vehicles give us the chance to reduce our noise pollution too.

According to World Health Organization (WHO), road traffic is the number one cause of community noise in urban areas. The recommended level of noise for residential zones by the WHO is 50 decibels, a quantity which is almost always widely overpassed in developed countries.

The main consequences from noise pollution are several health problems, such as hypertension, hearing loss, sleep difficulties and high stress. All these factors contribute to decrease the quality of life of a person, which may probably lead to a reduced life expectancy.

The possibility of having a world with silent vehicles would be a tremendous leap forward in the matter of public health. Therefore, it would be obvious to think that the decision made by the European Union is a big mistake. However, we must also try to understand how the noise could help people who might need it.

When I first talked about the AVAS on the forum, I exposed the case of somebody with sight problems who might need the noise of a vehicle to know where it is so he or she can avoid it. Crossing the street for blind people in a world with silent cars would be quite a difficult and dangerous situation for them. As a matter of fact, not all the streets have traffic lights which make noise when the light is green for pedestrians, and some streets do not even have traffic lights.

This is why I think that although people like you and me do not need this noise because we are perfectly capable to see when a vehicle is approaching, and we might think at first that these new policies are nonsense, we should also try to think about people who could find the noise helpful in their daily lives. I also wanted to clarify three details.

1.   Electric vehicles are not completely noise-free. Any electric vehicle displacing at a speed of 20 km/h or above will make noise due to the friction between the wheels and the road.

2.   As far as I am concerned, the sound produced by the AVAS will be lower than the one produced by a combustion engine vehicle and it supposedly designed not to be very annoying.

3.   If the vehicle is stopped, the AVAS will not work, therefore, this means that vehicles trapped in traffic jam or just waiting for a green light at pedestrian crossing, will make no noise.

To sum up, and after thinking for a while, I believe that the decision taken by the EU is the right one. Electric vehicles are extremely safe for their occupants, and from now on they should also be safer for pedestrians. And regarding the matter of the “opportunity cost”, noise pollution will be reduced anyway due to what I explained in the bullet points 2 and 3. Therefore, I think this is a situation in which all of us end up winning.

Regards,
Pablo García

Re: Electric Automobiles Safety
« Reply #3 on: 10 September , 2019, 19:02:45 pm »
Good evening, everyone,

Pablo, thanks so much for this interesting topic! After my friend José Javier already brought up some questions, here are two more that just came to mind.

1) Yes, after the new policy by the EU, the noise of electric cars will increase on purpose, increasing safety on the roads in the process. But who decides when "loud" becomes "loud enough for safety" or "too loud"? This seems like a matter of opinion thing only and should therefore be only decided by a larger group of people, right?
2) As you brilliantly explained, the strategical positioning of the battery in an electric car and the surrounding titanium hull make the entire battery pretty safe from any damage. But as you also mentioned, the weight massively increases, therefore making braking in emergency situations more difficult, if my basic understanding of physics is right. That does increase the danger of a bigger hit in case of a sudden crash, right? What are the plans about that?


All the best,

Matthias

Re: Electric Automobiles Safety
« Reply #4 on: 11 September , 2019, 13:15:57 pm »
Hello Matthias,

Thank you very much for showing this interest in this topic. It is something that makes me really glad. Now I will answer your doubts.

The law which establishes the whole legislation about the AVAS is regulation 540/2014. In this text, it is specified the exact quantity of decibels that must be produced by electric automobiles. That quantity varies depending on the kind of vehicle. For example, a large-tonnage vehicle such as semi-truck, must emit a louder noise than a sedan.
 
The regulation classifies the vehicles into two categories. Vehicles used for the carriage of passengers, and vehicles used for the carriage of goods.  The decibels emitted by the vehicles go from 68 in the lowest case to 82 in the highest.

If anybody wants to check this out, I leave you a link to the document of regulation.The level of decibels that every vehicle must produce is explained in the annex III, on pages 32 and 33.

https://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=CELEX:32014R0540&rid=2

Getting to the point of your question, the noises that each electric vehicle must produce are proportional to the noises that an equivalent combustion engine vehicle should emit. For example, an electric SUV with 400 horsepower should produce a noise a bit less loud than a combustion engine SUV with approximately the same horsepower. Therefore, as the sound would be similar in both cases that noise would be as “safe” as the one generated by an equivalent combustion engine automobile.

Regarding your second question, the theory you have raised makes a lot of sense. If this were the case of a combustion engine car the extra weight would suppose a serious danger for vehicle because as you said it would take much longer to brake and stop the vehicle.

Nevertheless, with electric vehicles the braking is much more instantaneous than in a conventional automobile. As soon as you take your foot off the pedal the vehicle begins to decelerate drastically. In fact, I have recently read in a study that the braking of an electric vehicle is 2.5 times faster than the braking of a combustion engine automobile. The combined braking power of an electric motor and the own brakes should be more than enough to stop the vehicle in a fraction of time if it is necessary. However, the possibility of avoiding a crash is something that also depends strongly on the reaction of the driver.

I hope I have solved your doubts.

Kind regards,
Pablo García