"Tesla Motors's recent five-star sweep in the National Highway Traffic Safety Administration (NHTSA) safety ratings shed light on an important aspect of electric cars: They're inherently safer than vehicles powered by internal combustion engines."
Charles, that's great, one more reason for opting an electric vehicle. I think apart from that energy star rating also has to be done with EVs.
"Gasoline is poisonous, forms explosive mixtures with air, and is quite flamable. Batteries - because they carry both fuel and oxidizer - can burn without air. The better the battery the hotter it burns. The Li Ions are pretty good at doing the thermite thing. Overall, I do not feel either one is particularly "safe", just different risks."
Fred, you are right; risks are associated with all source of energy. The only question is which is minimal and economical
Well, I think - based on some very vague observations, the ICE can be very reliable and about as safe as any other rapidly moving vehicle with slow witted humans in control. Minor design and manufacturing errors can make it unsafe at any speed. Similarly the battery car can be extreemly safe. And while it may do a thermite thing, it is not as likely to spray you with burning fuel when ruptured. Unfortunatly the failure mechanisms are less familiar to both the typical user, the maintenance personel, and the designers.
Of the two - however - only one gets you to work when solar/wind/nuclear are the only inexpensive energy sources and gasoline tops $4 a gallon. And a bit odd at that. I thought coal-oil (nuclear assisted or not) was around $2/gal which should mean our very cost conscious market should now be producing coal oil for our cars, not gasoline??? Is there a problem here way way beyond just the obvious one with a (relativly) new battery technology, and it's annoying limitations???
Chuck, Excellent post and interesting angle on Tesla's success. Certainly this is a company that is red hot in terms of perception and innovation> Safety isn't the only reason to buy an electric car but it definitely adds to the value.
While the electric cars may be passing most of the NHTSA safety tests with flying colors, they still have some underlying problems that will make sure they do not become an entirely viable alternative anytime in the near future. For instance (and this is one of the most serious problems) they have serious shortage when it comes to power storage. The power can only last so long and its not like you can drive into a gas station for a recharge as you would with an ordinary car.
anandy, it's true there are energy storage issues.
Leatherman tools, oscilloscopes, DVMs, guns, are examples of extremely useful products of which there are no universally perfect configurations.
Cars have been that way for a long time. Somehow, people have always wanted a sporty, economical, attractive, fast, four-wheel drive, comfortable, spacious, freight-friendly, 7 passenger two seater with a manual, automatic transmission, multi-fuel capability, iPod electronic dash that any teenager or housewife could self-service. There are inherent conflicts in that imaginary list, as you can see!
I've always told my friends who have never done a product design that all clients want someting that does everything for nothing, now. Easy peasey, right? If you are an engineer, you know exactly what I mean. THey don't get physics OR economics!
The Tesla, like my Honda Insight, isn't a vehicle for transporting sheet rock or plywood or casual off-roading. It has to be employed within its capability envelop. That envelop (moving ONE person from point A to point B, within town or on short interstate trips) covers a lot of US daily drivers, perhaps the majority. The incremental infrastructure to make this viable isn't that huge. I think the problem of charging is a red-herring. A Tesla, if I had one, would meet 95% of my transportation demands. Maybe 99. If I had the money to waste on one, I would have enough to rent a Tacoma pickup when I need one, which is annually.
These guys are on to something, I think. I think they'll push the lagging buzzards at Ford, GM, and the rest forward. These cars are selling like hotcakes, priced like Mercedes. THe Big 3 have been sitting idle, completely ignorant or dismissive of the market potential. (Think Apple versus Blackberry/RIM.)
The jury is still out. We have not had enough EVs involved in accidents in wet weather conditions to tell. I pray for the first responders who encounter wet metal, crushed into a 300 VDC battery. Occupants likewise must be very careful steping onto wet ground from a similarly damaged vehicle.
You need to reread the article. EVs are different because they have different design constraints. As the article points out, an EV isn't just a convential vehicle with the IC engine ripped out. The closest one can come is to perform the same functional test on each type of vehicle such as driving them into a rigid barrier at a controlled speed, crash test dummies on-board. Of course, certain design principles do contribute to basic safety and some vehicle designs incorporate them to a lesser or greater extent; but, I don't think we should argue that we should only compare vehicles with equivalent crush zones or only vehicles with a passenger capsule design against each other. Luxury features are not primarily safety features so likewise a comparison of only vehicles in a given price range doesn't make sense either, particularly if some economy vehicles would prove to be safer than some luxury ones; in fact, one can point to some very expensive vehicles with very poor roll-over characteristics. Where you might have a point is that the level of challenge might meet the level of risk; for example, a vehicle with a top speed of 150 mph might have to meet a higher standard than one that can only reach 85 mph.
Truely a misleading article tring to take a rating for the Tesla and tranferring that good rating to all EV vechiles.
1. The Telsa is not your normal EV car. It is an extreme luxury car replacement Think BMW so should be compared to such. It is very large in size for an EV so it benifits heavily from this size issue. This rating does very little to transfer to other EV's which are like Yugo's and would easily be crushed like a bug in a true accident. Their is a whole class of small enclosed EV's which are not even rated as standard cars, because they could not pass current auto standards.
2. As engineers we all know the results are only as good as the tests. These tests were written for gas vechiles developed to test for common failure modes fo gas vechiles. The rollover test came about after top heavy vechiles rollover became common, Rear crash test from the failure of Pinto et al to protect the fuel tank.
When testing an EV you cannot use the same standard, a common goverment mistake. EV's have their own set of failure modes that need tested sadly we will not know many of these until they become more widely accepted. One we do know and I cannot tell you if their is a test for, is battery rupture and latter meltdown by fire.
I often tell non-engineers that we tested something, but that doesn't mean it's good.
It means it passed the test we gave it, using what we used, when we tested it. It has a moderate predictive value. I have made a career troubleshooting designs that passed test and didn't work. Hell, at the aerospace companies I worked for (Martin and Raytheon) as often as not, when Test would find a failure of a product to meet specs, the product engineers would just change the specs to conform to test results.
Still, the specs here are how the car reacts to crashes, which apply to all vehicles. A Yugo isn't going to get 5 stars across the board like a Mercedes will. The Mercedes is undeniably safer. So is the Tesla. Without a doubt.
Does it transfer to smaller EVs? Probably the rollover does. Maybe the gas issue. The electrical problem is a real one, and I'm with you on that. Just because those lithium batteries are the same as those in your iPhone doesn't make them any safer. Look no further than the Boeing Dreamliner. QED.
More importantly, you can't test quality in. When it comes to safety, you have to begin early in design to design safety in. In a complex system it is unlikely that all of the potential safety challenges can be thoroughly tested for in any practical amount of time. Also, as has been commented, one tends to test for what one imagines to be the most important challenges while real life has a way of creating challenges that can only be imagined after the fact. And your mileage may vary. It is practicaly impossible to obtain statistically valid samples of most safety concerns.
Looking at the stats for vehicular fatalities, a disturbing proportion of them are due to fire with a significant portion of those not the result of a collision or other accident. Yet, safety testing does not dwell on the involvement of fire; in fact, they usually put any fire out before it plays out (crash test dummies and instruments are expensive). Human factors also play an important part since about 1/3 of fire fatalities occur when persons attempt to extinguish the fire. Gasoline burns and in a broad range of conditions explodes. Part of the problem is that this is common knowledge so it goes under-examined with respect to vehicle safety. They test TV recliners to see how rapidly they become consumed by flame but not vehicles.
Good points about the fire issue. As always test results are only as good as the test.
To all who think I hate EV's I do not, I currently use an E-mower and E-chainsaw, E-weedeater (i hate small gas engines). and when I can afford a spare vechile I would love to make an EV-Jeep. As an EE engineer I love to mess with E-stuff. It just burns me when people attempt to push their case with false or skewed data.
EV should stand on the own X-batteries with the pros and cons clearly marked.
I particularly like the one that we can't imagine what the real world shortcomings and risks are until we get some substantial experience with the tech. It's a chicken or egg problem, though. Looks like we chose one and now, we'll see what happens in a few years of highway experience.
Tesla is forcing the issue. For good or bad, they are filling up the sample pool. Most things in life and engineering trade off something or other for something else. If this is like anything else I've seen, worst case we'll probably see a change in the character of risks, and best case we MAY see an overall decrease in risks.
The one fly in the ointment is economics. If we put $70,000 into a Yugo, I'm betting it could be made pretty safe. But the market would not tolerate it. The chief benefit of the Tesla is that it is clearing SOME of the blockages that have been chorused for a long time.... people won't buy it.... you can't recharge it.... it won't go 1000 miles... who will maintain it..... batteries are heavy and unreliable....
I'm impressed anyone can build a car (that isn't a dune buggy!) and steal business away from Ford, GM, BMW, and Mercedes.
What about driving through high standing water. I know that we're taught to never drive through flood waters, but there have been many times that I've had to drive through high standing waters to get somewhere. It's bad enough on my Trans-Am that the air intake is down low, inviting hyrda-lock, but what would an electric car do if the motors or batteries became immersed?
On a related note, when railroads were transitioning from steam locomotives to diesel-electric locomotives in the 1950s, they quickly learned that in flooded areas, you want to use a steam locomotive instead of a diesel-electric locomotive!
There is so much wrong with your post, I'm not sure where to begin.
1. The ratings don't transfer between cars. Every car is tested on its own. The article pointed out that when designing an EV, certain safety improvements come along even if you're not designing for safety. For example, lower center of gravity, no big block of iron directly in front of the driver, etc.
2. The tests were not "written for gas vehicles." They were written for the cars we drive and how we drive them. That testing shows that a sports car won't roll over as easily as an SUV is just as pertinent and valid as the test that shows an EV won't roll over as easily as an ICE car.
If other safety issues arise that are unique to EVs, I'm sure NHTS will start testing for them and rank them. Until then, they test for the most likely accident types in our driving.
Rollover was a, mostly overblown, concern with Jeeps and SUVs. Tesla is designed from the ground up as a sports car. Sports cars always have a low center of gravity to enable faster cornering. Although I will give a slight nod that if designed right, EVs have the inherent ability to always have a low CG.
"So the shock wave is pretty much transferred to the area directly behind the engine, with minimal energy absorption." – This is just nonsense. The engine block is not rigidly fixed to the frame of the car so no 'shock wave' can transmit through it. It also has something called mass. The mass of the engine will help work against the momentum of the impact. The engine block will either shear its mounts or cause the frame to bend absorbing energy. It also gets pushed into the firewall in a crash which will absorb more energy and prevent it from entering the passenger cabin. This just sounds like propaganda; knowing one of the biggest EV weaknesses is actually survivability.
"You don't have a highly volatile liquid onboard, which can quickly get away from you during a crash and become a real problem." – This is a fair comment. But let's not forget that EVs have been burning up all over the place due to shorting of the high energy storage. In my mind this is a wash between the two if EV electrical systems designed with collision survivability in mind. Gas burns when it finds heat and air; high current can melt, heat or burn any material. Gas can explode, but in car wrecks it just burns. Batteries can explode, but not very impressively.
All in all I say a score of one to Tesla (not all EVs) and minus two for David Cole.
I congratulate Tesla on doing so well in the NHTSA crash tests. The tests are carefully designed to try to predict surivivabilty of the occupants in a crast situation of fairly limited scope. Controlled crumple zones reduce the perceived g-forces seen by the occupants; these crumple zones are the result of a great deal of analysis of materials, fastentings and assemblies. A 5 star sweep of all tests indicates some very thorough engineering design and a good understanding of composite materials. The Tesla S is designed to fit a small market nitche and it does that very well. It is not a 'peoples' car but the people who can afford to buy it are enriching their own lives as well as allowing Tesla to continue to further the science of EVs. It is one step on a long road - imagine what our greaet grand children will be using for transportation - this vehicle and others like it are proving - or disproving - the viability of EVs and composite technology. Wish I could justify one. Attaboy Tesla! Nice article Charles.
Yes, Tesla has done a great job. HOWEVER, let's not forget that this is a REALLY expensive automobile with lots of functional shortcomings. Let's see how they do on a true 4 passenger vehicle with a 400 mile range for $15,000 delivered.
Hmmm - most accidents I've witnessed involving internal combustion powered vehicles do not involve fire or explosions. Considering how many such vehicles are on the road, I believe they have a pretty fair track record when it comes to detonations.
I understand the water and high voltage danger, but I'm curious as to what kind of risks are at play in the event the Tesla's battery block were to be torn apart in an accident.
The problem with the battery pack damage is that Lithium is hughly reactive. When a battery pack of EV size ruptures the cell can go into an overheated runaway state and basically melt down, catch fire, off gas some pretty nasty stuff.
One of the scariest parts about this is it does not need to happed right after an crash. If the casing is cracked their can be a slow reactive build up that can take minutes, hour up to days and than boom you have battery thermal runaway.
This problem is being worked on and will eventually be solved their are new battery chemistry and assembly systems that prevent this but most current EV battery packs have this problem. Is it worse than a gas tank rupture?? Like all else it depends but it is one of the often not discussed issue with EV vechiles.
Leto, after a collision and after I am out of the vehicle it is a lot less important what happens next. All of the terrible problems happen before anybody gets out of the vehicle, all of the fires after that may be quite inconvenient but they are seldom life threatening. Yes, having a $15K battery pack explode is a pain, but not a tragedy unless it happens before you get out of the crashed vehicle.
I have watched a lot of crashes at a test track and mostly there is not even any gas leak after collisions less than 45 MPH. And at the higher speeds you are more likely to be injured by that airbag explosion. AFTER ALL, HIGH SPEED COLLISIONS HAVE PROVED TO BE DANGEROUS! You will notice that all of the automakers recommend never bashing into anything with their product.
I am not saying that a battery pack is more or less dangerous than gasoline. I was answering the question about what is the problem with batteries in an accident. Whenever you have large amounts of energy stored it is dangerous. The extra or different danger in a battery pack is the crack or damage to the pack is not known so in a relatively small accident if you crack your battery casing you may go on as all seems well at some point latter the pack melts down. If it happens to be parked in your garage at the time garage fire. If you are driving it lots of smoke and quite possibly another accident as you loose control.
I haven't had a chance to read all the comments here, but I've looked at a few and some are making the case that lithium-ion chemistries aren't safe. And, yes, it's true that lithium-ion (particularly cobalt oxide chemistries) are more energetic than other battery chemistries. But bear in mind that gasoline has a much, much higher energy density than any battery...yet engineers have been able to make gasoline-burning vehicles very safe.
I don't know that a lithium battery pack is more dangerous than a CNG, propane or gasoline powered vehicle. Any material that can 'energetically disassemble' is a hazard. As a retired Volunteer Fire Fighter/EMT who has performed many extrications, I understand that hazards are rife at any accident scene and all Fire Fighters are trained and aware of them. I don't know of any energy source that is intrinsically safe. It does seem that as vehicles have more and more safety equipment installed drivers seem to consider collisions as more an inconvenience and less of a hazard.
@Arch, as expensive as the Tesla vehicle is, I would expect that those owners wll pay a lot more attention to driving than the average driver does. Plus, they are probably more focused in all of their activities.
If it were evaluated it would probably become clear that most folks don't have accidents, but that a smaller percentage of folks have most of them. And that probably relates to the type of vehicle that they select. My point being that probably side impacts will be a lot less of a problem for Tesla owners.
really, I don't driving a Tesla will stop a drunk driver or some teen texting from crashing into you. Accidents happen now matter how cautious of a driver you are so I would never assume that just because these buyer are more cautious they are much safer from accidents.
Leto, you are probably correct, but I was thinking that if I were driving a car that expensive I would be very careful indeed. Even with my present car I have avoided being hit by taking the initiative and getting out of the way of some people. So it is possible for some of us to pay enough attention to avoid the errors of others. At least sometimes. But there are a lot of other folks who would never consider getting out of the way of a car sliding towards them, because the have a right to be where they were. I consider that to be quite dumb.
When I had a front-end collision in my Nissan Rogue, the EMS responder pulled out a pair of wire cutters and cut the positive battery cable, because that was standard operating procedure in a vehicle accident. What the genius did not, apparently, notice was the big boxy area just off the battery terminal on the cable that contained a fusible link, which disconnected all power upon impact. That battery cable costs $150 with the fusible link from the dealer, but the fusible link only costs $70 to replace. It begs the question, in an electric car accident, will the EMS responder cut the battery cables on the electric car simply because it is 'SOP'? Another thing to consider is the toxicity of the leaking fluids from the batteries. Do they pose a health risk, and if so, how do they safely clean up the accident scene after a collision? Even though there is little risk of fire from the electric vehicle, what about any gasoline-powered vehicles also around the scene or involved? I do not know how much taining local fire departments give their people about automotive accidents, but I am willing to bet that it is not much. As I said, the battery cable on my Nissan Rogue had a safety cutoff system to do exactly what the wirecutters did, without damaging the cable. Without proper training, a well-meaning EMS responder may do more damage than good when trying to minimize the risk of a fire or injury to others. I worry about this, as we all should. I would not feel so badly about paying a higher price for a vehicle like the Tesla, if some of that money went to training fire departments in my area to respond properly to accidents involving one. No, I don't intend to have a front-end collision ever again, but I never intended to have the first one either. No matter what, I believe that a safer vehicle should include training for those responsible for public safety on how to handle those accidents that are bound to happen with that vehicle.
Excellent post Charles. If I may, are there NHTSA standards for ICEs, EV and Hybrids or just one standard for all types of vehicles? It seems to me the three points you make would be relevant to all vehicles of differing types. There were many excellent comments regarding your post but those safety factors mentioned I feel certainly apply.
I don't know the definitive answer to your question, bobjengr, but I'm not familiar with any NHTSA standards that target only EVs, ICEs, or hybrids. Is there a reader out there who can enlighten us on this?
NHTSA mandates three major types of crash testing:
1. Frontal impact. There are several subcatagories based on overlap between vehicles (100% overlap, 50% overlap and 25% overlap). Some impacts are with a massive concrete barrier. Others are into softer "deformable" barriers.
2. Side Impact. A test sled is driven into the target vehicle at a specified speed and mass.
3. Rollover. The test vehicle is driven or pulled onto a helical ramp which then triggers the rollover.
There is also some rear impact testing, mainly to verify head restraint performance, seat attachment robustness, and fuel leakage.
IIHS (Insurance Institute for Highway Safety) often performs additional testing or testis to more severe conditions than mandated by NHTSA regulations.
The auto industry has learned a lot about how to improve the crashworthiness of vehicles over the past 30 years. However, Tesla has a definite advantage because they began with a clean sheet design. They could then address all the crashworthyness regulations from the beginning, making design decisions that could optimize crush zone characteristics which reduced occupant injuries.
Disclosure: I spent a majority of my career designing electronics to mitigate occupant injuries in crashes.
@ Rob Spiegel, it is clearly stated in the article that EVs have at least three inherent safety advantages over their gasoline powered counterparts. But I think it is more about Telsa than EVs because some other EVs by other companies got four stars. There must be something more than these three inherent advantages in Telsa's Model S that got it five stars.
Telsa's publishing of safety news certainly leaves other companies with fewer choices. If they counter Telsa by publishing such news, they will be advertising against their gasoline powered vehicles. On the other hand, if they don't publish, they will be compromising their EVs. I believe, however, that it will not hurt them as much as it seems apparently. Because what they might lose in gasoline powered vehicles they will gain in EVs.
I too would like to know if the battery packs are damaged and leaking is it an environmental hazard? Certainly not all electrolytes are created equal and some of them must be toxic. It would be interesting to know how first-responders or clean-up crews deal with it.
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