[procrastinator]

We are looking for a new car with safety being one of the important aspect.
Although we can speculate but I would like to know about hot selling Elite i20 and Kwid.

I wish to know about Brio/Amaze/Jazz as no car from Honda stable has been crash tested.

It would be interesting to see how Indian manufacturers cars Zest/Bolt/Tiago or KUV/TUV fare in crash test.

Originally Posted by balajisv

The last time such tests results for Maruti Suzuki Swift were out, they had absolutely no impact on its sales! People continued to buy them like cakes !!

Well, We have dropped the current swift from our new car search despite being VFM in every department (Power, Ride and Handling , FE, Reliability)

[Lalvaz]

Originally Posted by AutoNoob

In such a unequal sized collision, the heavier vehicle experiences lesser change in its velocity than the lighter car. Thus, inline with law of conservation of momentum, the impulse (rate of change of momentum) experienced by the smaller car is much higher the bigger SUV. Therefore, the smaller (lighter) car suffers more damage. Also, in most Indian cars in mass segment the structural integrity is questionable, the occupants are at a higher risk, even though both vehicles were travelling at same speeds.

The relative speed is important when the structural deformability of one body is significantly different than the other. Just think if the damage will be similar (1) in a head-on crash between a car and a train travelling at speeds of 30km/h each (2) car crashing in a static train/ wall at 30km/h. I am not quoting the usual highway scenario of car-truck collision as the mechanism is totally different due to no/pseudo FUPDs/RUPDs.

This is my understanding, and I'll be happy if you can correct my errors. Thanks !!

If only life were that simple. You're right in inferring that in a collision between a car and a train, the car will suffer significantly more damage than the train. Force = mass x acceleration. And mass of a train being significantly higher, the force of the train will result in much more energy transfer to the car and hence greater displacement of the car. However the damage to the occupants in a collision between a hatchback and a sedan or even an suv need not be as pronounced as that. If the car is well designed and engineered, it might be able to protect its occupants in a 56 kph collision. I remember the Mercedes smart car was tested and could safely withstand collisions with cars twice its weight with no fatal injuries to the passengers.


So, yes, weight of the colliding bodies plays an important part in the end result and the consequent displacement of the bodies, but the displacement does not necessarily mean a fatality.

[AutoNoob]

Originally Posted by Lalvaz

So, yes, weight of the colliding bodies plays an important part in the end result and the consequent displacement of the bodies, but the displacement does not necessarily mean a fatality.

The example of car-train collision was just to make things more apparent. You rightly said "displacement does not necessarily mean a fatality". It depends upon the structure; how effectively it dissipates the crash energy away from the occupants. In F1 cars, the structure is designed to break apart and the fragments carry much of the energy far away from the driver. The cockpit structure indeed plays the role, but it can't be looked in isolation.

The weight of the vehicles brings in the momentum and resultant crash impulse. The outcome of crash depends on many factors; I gave one example in my earlier post. Many outcomes are possible in real life crash. I just wanted to highlight that Mythbusters demonstrated one outcome based on some specific conditions, which can't be generalized across all crash scenarios.

One more seemingly weird example : A battle tank hitting a rigid wall will suffer much more damage than a car hitting the same rigid wall at the same speed; and occupants are at a greater risk. It is because the structure of the tank is not designed for such an impact. (Rigid wall : a body which will suffer only minor damage and will not move during the impact, unlike the scenarios where the tank ploughs over/ through it).

[asr245]

Originally Posted by AutoNoob

I just wanted to highlight that Mythbusters demonstrated one outcome based on some specific conditions, which can't be generalized across all crash scenarios.

Of course. Those crashes or even the ones conducted by Global NCAP assume the crash structures play a role in a crash. In India, where most buses & trucks do not have those low crash bars (don't know their exact name), it is very likely that a car would go under & crash structure wouldn't even be in play. I don't think an SUV would do much better vs a truck/bus. I am quite sure even the airbags (if present) wouldn't be activated in such cases.

The only point made earlier was that everything being same, relative speed of 2x does not mean crash speed of 2x.

[AutoNoob]

Sharing the following document for everyone's reference. I hope this would be helpful.

Global Automotive Safety Regulations in Nutshell - January 2015
Source : http://www.wissenbaumllp.com/download.aspx

The download section on website requires some basic registration, so sharing it as attachment. I have deleted the advertisement pages to reduce the file size below 5MB limit.

[RJ411]

Originally Posted by JonSnow

It may not have impacted sales, but definitely had an impact on how I looked at cars and also how I drive.

200% correct. I bought a bare bone used WagonR LXI with absolutely no knowledge on safety and any other parameters.

After spending time with this forum I realised the importance of safety and driving knowledge. If I had been here earlier I would have definitely gone with a safer car.

The knowledge gained here is priceless and I am trying to pass it on to my friends and family whenever I get an opportunity.

There is a funny dialogue that comes in one of the tamil movie which says "Information is wealth". With respect to this forum its priceless and life saving for many

[srh]

Originally Posted by AutoNoob

I am aware of this video and the Mythbusters have rightly busted the myth, but with a caveat "crashing of identical cars". Here the structures of the two cars almost equally share/ dissipate the crash energy. Somehow, I am not at all surprised to see the general inference that you all have derived; most people get caught in this over-simplified 'lab' test. I wish the real life scenarios are also similar and thus occupants face less danger.

However, they aren't. I too might have been over simplistic in my earlier comment while trying to relate it more to the real life scenarios and thought process of average customers (and leaving out the bits of additional physics). Please consider the following in a real life crashes :

The scenario of having crash between two vehicles with similar masses and structural integrity is possible, but probability is much less than that involving two different vehicles. This becomes significant in case the two vehicles have significant difference in weight & structural integrity (say a K-Segment car and a SUV). In such case, due to the high mass difference, the SUV acts as more like rigid barrier. And with the SUV as frame of reference, the smaller car approaches it at a speed equivalent to the actual relative speed between the two vehicles.

In such a unequal sized collision, the heavier vehicle experiences lesser change in its velocity than the lighter car. Thus, inline with law of conservation of momentum, the impulse (rate of change of momentum) experienced by the smaller car is much higher the bigger SUV. Therefore, the smaller (lighter) car suffers more damage. Also, in most Indian cars in mass segment the structural integrity is questionable, the occupants are at a higher risk, even though both vehicles were travelling at same speeds.

The relative speed is important when the structural deformability of one body is significantly different than the other. Just think if the damage will be similar (1) in a head-on crash between a car and a train travelling at speeds of 30km/h each (2) car crashing in a static train/ wall at 30km/h. I am not quoting the usual highway scenario of car-truck collision as the mechanism is totally different due to no/pseudo FUPDs/RUPDs.

This is my understanding, and I'll be happy if you can correct my errors. Thanks !!

Couldn't have stated it better. The difference in mass/ momentum and deformation/ energy absorption makes the scenario veer increasingly from a crash between two similar bodies towards crash with a rigid barrier at the sum of individual speeds.

[shashanka]

Originally Posted by AutoNoob

I am aware of this video and the Mythbusters have rightly busted the myth, ...........and I'll be happy if you can correct my errors. Thanks !!

Moral of the story - buy an SUV, not a feather light hatchback! And make sure its a proper SUV (body-on-frame, ladder-frame accepted!) - no monocoque wannna-be's will pass muster!

No, but seriously, real-life scenarios are indeed surreal-ly different from the lab-generated situations most crash tests simulate.

And good physics notwithstanding, the direct relationship, popularly assumed, between structural integrity and kerb weight - I admit to have been guilty of this too & even now am reluctant to let go! - is suspect (in my mind certainly) after the Toyota Etio's (kerb wt 900 kgs, length 4265 mm, 1.4 L CRDE, as per CAR DEKHO!) 4-star safety rating recently.

[asr245]

Originally Posted by shashanka

Moral of the story - buy an SUV, not a feather light hatchback! And make sure its a proper SUV (body-on-frame, ladder-frame accepted!) - no monocoque wannna-be's will pass muster!

No, but seriously, real-life scenarios are indeed surreal-ly different from the lab-generated situations most crash tests simulate.

Maybe I misundertand your comment, but I think you have it wrong. A feather light hatch designed with safety in mind (I20/Jazz with airbags) will be safer than let's say an old SUV (say bolero). There are crash test vidoes of these too on youtube. More weight means more momentum but not more safety.

And a modern monocoque SUV with safet equipment (like XUV) is probably more safer than say a Scorpio/Safari.

[CrAzY dRiVeR]

Volkswagen
Maruti Suzuki
Ford
Toyota
Hyundai
Datsun

Good to see many manufacturers being tested. However, I would like to see how the other brands fare as well in this set of results. Hopefully includes atleast one models each from Renault (Kwid) , Honda (Amaze), Mahindra (TUV), Nissan, FIAT etc.

[volkman10]

Renault Kwid crash tested by Global NCAP.

The Kwid is learnt to have got a low score in the crash test, based on comments and suggestions for improvements, Renault has already reinforced the Kwid, which could again be crash-tested.

the Kwid is part of the set of seven cars that have been crash-tested under the agency's Safer Cars for India campaign -

Thus far, seven compact car models from India have been crash-tested by Global NCAP. This does not include the Toyota Etios Liva voluntary crash test.

http://www.autocarpro.in/news-nation...bal-ncap-19786

[Latheesh]

I would like to see the result of Baleno Indian version. Let us see if it can score 4 or 5 *

[volkman10]

Positive on Safer cars for India!

https://www.youtube.com/watch?v=2rL7c74veGM

[volkman10]

Originally Posted by AutoNoob

Now, increase the speed of the individual cars, in the example above, to 40km/h (again not so frightening speed), the relative speed increases to 80km/h and result of crash is disastrous.

Originally Posted by asr245

Actually that's incorrect. While relative speed is doubled, energy that needs to be dissipated by the crash structures of the car are about the same as a car travelling at 40kmph into an immovable, non-deforming object. Used to think the same till it was cleared up by mythbusters on Discovery (or was it NatGeo).

Here is what GNCAP has to say on why 64km/h is the speed at which cars are crash tested,

https://www.youtube.com/watch?v=4wWsCadsEqw

[shashanka]

Originally Posted by asr245

Maybe I misundertand your comment, but I think you have it wrong. A feather light hatch designed with safety in mind (I20/Jazz with airbags) will be safer than let's say an old SUV (say bolero). There are crash test vidoes of these too on Youtube. More weight means more momentum but not more safety.
And a modern monocoque SUV with safet equipment (like XUV) is probably more safer than say a Scorpio/Safari.

I accept that a modern monocoque like the XUV (at 1700+ kg) is probably safer than the old Bolero. On the other hand another modern monocoque like the B-RV, with dimensions more or less comparable to the XUV, weighs in at 1265 kgs! I'm afraid with all the mental gymnastics at my command, I find it difficult to accept that the B-RV is safer! And despite all the jargon that the boffins at most of the mass production auto MNCs come out with about their cutting-edge metallurgy etc, I have always taken it all with a pinch of salt! The Volvo S60, a contemporary moncoque from a mfr. with a formidable safety record (which has comparable dimensions to the XUV and the B-RV) weighs in at 1500+ kg. So, while it may hold good to an extent, I find that for me, the jury is still out on the new mantra that more wt = more momentum, but not = more safety!