[acurafan]

Originally Posted by apachelongbow

lets understand NCAP crash test first. It only measures impact at 64kmph when the car hits a stationary barrier (supposed to show a rear ending impact) and the impact is measured. How realistic is this scenario in India?

Sorry to say, but this is very untrue. NCAP safety tests are one of the most multi-faceted test available in the industry and they are constantly modifying the test procedure. I work on active safety and it is a constant challenge for my team to keep our nose ahead of the changing scenarios. Global NCAP uses a sub-set of Euro NCAP testing procedure, as the focus is primarily to evaluate developing nation models. So, zero star Global NCAP rating will always result in a similar score in Euro NCAP, but a four-five star in GNCAP does not guarantee the same rating in Euro NCAP.

To understand NCAP tests, there are mainly four categories of tests. The combined score is weighted average of the score in individual category. The final star rating is dictated by the minimum of star rating for each individual category. For example, five star rating in 3 categories and two star rating in 1 category results in a two star rating. This explains the zero star rating for some of the Indian models. Due to absence of airbag, these car scored zero star in driver or passenger protection bringing the overall score to zero. On the other hand, BMW Z4 scored five star in all but active safety category and was scored three star in 2015 Euro NCAP tests.

So the four categories are as follows:
a) Adult Occupant
b) Child Occupant
c) Pedestrian
d) Safety assist

Now if we look at individual categories, there are multitude of tests that contribute to the score for each category.
The Adult Occupant Protection score is determined from frontal impact, side impact and whiplash tests, which are carried out to evaluate the protection of adult driver and passengers offered by the vehicle.

Frontal Impact with deformable barrier previously used to test collision with 100% overlap but in recent years it has changed to 40% overlap which mimics the real world collision better. In the full-scale test, the car is driven at 64km/h and with 40 percent overlap into a deformable barrier which represents the oncoming vehicle. The test replicates a crash between two cars of the same weight, both travelling at a speed of 50km/h. Two frontal impact dummies representing the average male are seated in the front and child dummies are placed in child restraints in the rear seats.

In this crash, the vehicle structure is put to the test. Limited structural designs typically expose occupants to increased intrusions. Crash forces have to be efficiently directed to parts of the car where the energy can be efficiently and safely absorbed. The front crumple zone must collapse in a controlled way, leaving the passenger compartment as undeformed as possible. Rearward movement of the steering wheel and the pedals must be limited if serious injuries are to be avoided.

Full Width Rigid Barrier
This test from the name mimics driving into a wall, stationary large targets etc. The motivation of test although is to challenge the current design practices and to evaluate the effectiveness of the restraint systems.
In recent years car structures have become stiffer. This has helped to reduce lower leg and head injuries as the passenger compartment is less prone to collapse. However this also means higher comportment decelerations, which need to be dealt with by the restraint systems in the front and rear seats during the crash. These decelerations can lead to severe injuries, especially to the chest of the more vulnerable, smaller or elderly occupants.
Euro NCAP tests cars against a rigid barrier with full overlap at a test speed of 50km/h. A small female frontal impact dummy is seated in the front driver’s seat and in the rear passenger side seat.

This test places high demands on the restraint systems in front and rear seating positions. Strict limits are placed on the decelerations of the chest and on the degree of chest deflection and this, in turn, encourages manufacturers to fit more sophisticated restraints. The test complements the offset deformable test as a balance must be found between a restraint system that is stiff enough to restrain a male dummy in the 64km/h test and one that is compliant enough not to put injuriously high deceleration forces on a small female.

Side Mobile Barrier
This test is designed to mimic the side impact crashes. Compared to a frontal impact, there is very little space inside the vehicle interior in which to absorb energy and severe injuries to the head and the chest are common.

In Euro NCAP’s test, a deformable barrier is mounted on a trolley and is driven at 50km/h into the side of the stationary test vehicle at right angles. A side impact dummy representing an average male is put in the driver’s seat and child dummies are placed in child restraint systems in the rear.

The test ensures that there is adequate protection of the critical body regions. This has driven the strengthening the structures of vehicles around the B-pillar (between the doors), the fitment of side impact or curtain airbags in cars but also the development of less obvious energy-absorbing structures in seats and door panels. The timing and deployment of airbags must be very carefully controlled to ensure that they provide the greatest protection possible.

Side Pole Impact
This is to test impact that involve a vehicle travelling sideways into rigid roadside objects such as trees or poles. Often this is the result of a loss of control on the part of the driver, owing to speeding, misjudgement of a corner or because of a skid in slippery conditions. Such accidents are severe and the frequency of death or serious injury is high. I think we are familiar with a very profile crash that resulted in the death of Paul Walker.

In Euro NCAP’s test, a car is propelled sideways at 32km/h against a rigid, narrow pole. The car is placed at right angles to the direction of motion, or as is done from 2015 onwards, at a small angle away from the perpendicular. A single average male side impact dummy is placed in the driver’s seat.

This is a severe test of a car’s ability to protect the driver’s head. As the loading on the car is so localised, deformation can be very high and the pole can penetrate deeply into the passenger compartment. Without effective protection, the pole would strike the head resulting in serious injuries. Head protection airbags – often curtain airbags mounted above the side windows but sometimes seat-mounted thorax/head airbags – have become a common solution but great care is needed to ensure effective performance of such devices.

In addition to this there are tests for whiplash at different impact speed and also the active emergency braking upto 80 kmph in to static and slowly moving targets.

Other tests will be discussed in a later post.

[acurafan]

Originally Posted by heavenlybull

Pardon me but which were these 56km/hr crash tests these manufacturers claim they have already passed? This 56km/hr is just mumbo jumbo.

There are two different safety ratings. Euro NCAP is a voluntary testing which does not cover every vehicle made. For every new vehicle model, the test that needs to be passed is Whole Vehicle Type Approval by the regulation agency (Directive 2007/46/EC). Now this test is done at 56 kmph against a deform-able barrier with full overlap. This is not an easy test but most vehicle manufacturer know how to pass this. The problem appears mostly on small and medium overlap due to shearing stress on the vehicle frame which is what Euro NCAP tests at slightly higher speed (64 kmph).

Euro NCAP and other non-govermental testing agencies are constantly modiying their test procedures by analysing the accident databases such as GiDAS which has a very detailed analysis of every accident in Hannover and Dresden region that results in personal injury.
Vehicle manufacturers also use these databases to recreate accident situations and simulate vehicle performance.

The whole reasoning that the OEMs are passing the 56 kmph Whole vehicle type approval testing and should not be subjected to NCAP like testing is legally correct and ethically immoral. We can show our disdain by not buying such cars.

[acurafan]

Originally Posted by Rehaan

Could you also tell us more on how variants factor in to this? Is each variant tested separately? Is the scrore based on the middle variant, highest or lowest?

Any other details?

When a car is nominated for testing, Euro NCAP asks the manufacturer for information about the best-selling variant and the fitment of safety equipment across Europe. From this information the test variant is derived. In general, the test variant must have safety equipment fitted as standard (which typically is the top variant). In exceptional cases, Euro NCAP allows optional technology to be fitted on the test variant, but only if the option is available on a high number of cars sold and only for a short introduction period. From 2016, all cars have a basic rating, for which Euro NCAP uses a car fitted only with standard equipment. Some cars also have an optional, second star rating for which a car fitted with an additional ‘safety pack’ is used. For previous years, Euro NCAP tested cars which, in general, had only standard safety equipment.

Recently had a face to face meeting with Euro NCAP execs and learnt some of the backstory.

• EuroNCAP consists of 11 people. All actual testing work is outsourced to technical project management bureaus like the Dutch TNO. EuroNCAP itself is a nonprofit organization based in Brussels. The organization is funded by the European governments participating at EuroNCAP and by car manufacturers.
• Besides their own testing, EuroNCAP relies on competition between the OEMs. OEMs tend to buy and test each other’s cars and will tell EuroNCAP if the car of the competition does not meet a requirement.
• EuroNCAP does not do statistics. In EuroNCAP's tests, the car gets 1 chance. Manufacturers often complain and request tests to be repeated e.g. 100 times so they can score say 95%. NCAP explains to OEMs that when they gets into an accident themselves, they only get 1 chance too.
• EuroNCAP does not test at night or during rain. Reasons are limited capacities, and that most accidents occur during the day when it is not raining anyway (because people tend to drive slower when it rains). However, it is anticipated that in future, tests will be held at night to recognize pedestrian-related scenarios (EuroNCAP 2020).

[acurafan]

Creating a second post to discuss the follow-ups I promised earlier.

As I explained, there are four categories in the Euro NCAP testing.

• Adult Occupant
• Child Occupant
• Pedestrian Safety
• Active Safety

Child Occupant Protection
The assessment of Child Occupant Protection covers three aspects: The protection offered by the child restraint systems in the frontal and side impact tests. The vehicle’s ability to accommodate child restraints of various sizes and designs. The availability of provisions for safe transport of children in the car.

CRS (Child Restraint System) Performance is evaluated for most Frontal and Side Impact test except for the side pole collision test. The vehicle manufacturer is legally obliged to provide information about the use of child restraints on the seating positions in the vehicle. Euro NCAP checks how well different child restraints fit and verifies the protection offered by the recommended child restraints in the event of a front or side crash.

Since 1997, child dummies representing 1½ and 3 year old children have been placed on the rear seat of the car, in the child restraints recommended by the car manufacturer. In 2016, the test configuration changed and child dummies representing 6 and 10 year old children, seated on a booster seat or cushion, are used from that time.

Head movement, neck loads and chest accelerations are the main dummy criteria measured during the tests. The vehicle will be rewarded if test criteria remain low and if neither dummy was ejected from its seat or made any hard contact with the vehicle interior during the crash. This ensures that the child remains correctly restrained during the crash event.

Pedestrian Protection
The Pedestrian Protection score is determined from tests to the most important vehicle front-end structures such as the bonnet and windshield, the bonnet leading edge and the bumper.

In these tests, the potential risk at injuries to pedestrian head, pelvis, upper and lower leg are assessed. Cars which perform well can gain additional points if they have an autonomous emergency braking (AEB) system which recognises pedestrians.

Head Impact Test
To estimate the potential risk of head injury in the event of a vehicle striking an adult or a child, a series of impact tests is carried out at 40 km/h using an adult or child head form impactor. Impact sites are then assessed and the protection offered is rated as good, adequate, marginal, weak or poor.

The procedure promotes energy absorbing structures, deformation clearance and deployable protection systems such as pop-up bonnets and external airbags.

Upper and lower Leg Impact
To estimate the potential risk of lower leg, pelvis and upper leg injuries in the event of a vehicle striking an adult, a series of impact tests is carried out at 40 km/h using an adult upper leg form impactor. Impact sites are then assessed and the protection offered is rated as good, adequate, marginal, weak or poor.

The procedure promotes energy absorbing structures and a more forgiving geometry that mitigates injuries.

AEB Pedestrian Testing
This reminds me of the Youtube video of some Volvo execs who tried their own version of testing with live models and with a car that didn't have pedestrian safety tech built-in.

Euro NCAP tests three crossing scenarios, all of which would result in a fatal collision between the car and the pedestrian if the AEB system did not intervene: an adult runs from the driver’s side of the vehicle; an adult walks from the passenger’s side (two tests are done for this scenario); and a child runs from between parked cars on the passenger’s side.

These tests represent critical situations that often result in pedestrian casualties in the real world. Cars that perform well can be expected to have a significantly reduced risk of pedestrian accidents in real world driving. In many instances, AEB Pedestrian technology may not be able to completely avoid the collision. For this reason, Euro NCAP only rewards the technology if the pedestrian impact tests show that the car has a forgiving front design.

As far as I remember Volvo XC90 was the first car to get a perfect score for the active safety and avoided all three collision.

Active safety is a whole different topic and needs lot of time to go over

[GTO]

Acurafan, thanks for sharing! Moving your wonderful posts into a new thread so that no one misses them .

Moving this thread to the Indian car scene, keeping in mind the number of Indian cars that have gone through the Euro NCAP tests.

[Divya Sharan]

Thanks for the wonderful posts Acurafan!

I have a generic query - manufacturers have hit the safety bandwagon big time and they are providing their cars with a host of safety features like multiple airbags (6 to 8 or more), ABS, EBD, TCS, active braking, cameras, radar etc. But what about rear ends?

Will my stationary Volvo withstand a rear ending by a similar vehicle at 56 or 64 kmph? What measures do manufactures (plan to) take for covering the rear passengers?
How are rear end tests different in a hatchback w.r.t a sedan?

[rev_rohit]

Thanks Acurafan for this lovely and informative post!

It's really horrifying seeing videos of the tests and imagining yourself and your family members in place of those dummies.

Another point to remember is that protection will definitely be lesser at speeds exceeding the test speeds and without the proper use of the equipment ie. The restraint system.

Even rear occupants are not safe without proper use of seat belts. We must ensure seat belt usage by the rear occupants especially kids even in a 5*rated car.

Originally Posted by Divya Sharan

Will my stationary Volvo withstand a rear ending by a similar vehicle at 56 or 64 kmph? What measures do manufactures (plan to) take for covering the rear passengers?
How are rear end tests different in a hatchback w.r.t a sedan?

Very valid query, I think rear ending per se is not tested but whiplash protection by headrests and protection due to seats are tested in NCAP.

Secondly I think in frontal impact injury occurs because at the time of impact the body by virtue of its inertia moves a distance at high speed and is suddenly stopped by the impact on the dashboard or the steering wheel whereas in rearending incidence body is well cushioned by the seat and headrest that's why injuries are quiet less in severity and numbers.

Thirdly what I understand from the crash that in frontal impact speeds of the two vehicles are added, in other words a test speed of 64 kmph means two vehicles coming from opposite directions at a speed of 32 kmph will produce similar impact as that of a car at a speed of 64 hits another stationary car.

Correct me if I'm wrong.

[Thad E Ginathom]

Nice to see the new thread. Looking forward to more from Acurafan on this and other such topics

[Thumping Soul]

Aweosme post Acurafan. Thanks for sharing.

Now, i had a query. I understand that the car manufacturers are increasingly focusing on safety features. But could you also explain a bit more on the role played by structural rigidity of a car and the side impact bars in case of side impacts. How do cars with curtain airbags fare against the ones without it. This becomes more important from the point that typically kids are seated close to the windows, even in case of cars with child seats.

Would really like to understand the safety evaluations on these aspects.

Regards
Saurav

[alpha1]

Hi acurafan, this is a magnificent thread.
I had a question:

In the full-scale test, the car is driven at 64km/h and with 40 percent overlap into a deformable barrier which represents the oncoming vehicle. The test replicates a crash between two cars of the same weight, both travelling at a speed of 50km/h

What is the basis for deciding that two opposing vehicles at 50 kmph represents useful case. I have read that speed limits in Europe are in excess of 150-200 kmph and some places don't have speed limit altogether - shouldn't the tests be representative of the real life conditions?

[Turbohead]

Any idea how many cars are used up for testing? Do manufacturers take back the tested cars for R&D?

[acurafan]

Originally Posted by GTO

Acurafan, thanks for sharing! Moving your wonderful posts into a new thread so that no one misses them .

Thanks GTO. Really appreciate this.

Originally Posted by Divya Sharan

But what about rear ends?

Will my stationary Volvo withstand a rear ending by a similar vehicle at 56 or 64 kmph? What measures do manufactures (plan to) take for covering the rear passengers?
How are rear end tests different in a hatchback w.r.t a sedan?

Originally Posted by rev_rohit

Very valid query, I think rear ending per se is not tested but whiplash protection by headrests and protection due to seats are tested in NCAP.

Secondly I think in frontal impact injury occurs because at the time of impact the body by virtue of its inertia moves a distance at high speed and is suddenly stopped by the impact on the dashboard or the steering wheel whereas in rearending incidence body is well cushioned by the seat and headrest that's why injuries are quiet less in severity and numbers.

Thirdly what I understand from the crash that in frontal impact speeds of the two vehicles are added, in other words a test speed of 64 kmph means two vehicles coming from opposite directions at a speed of 32 kmph will produce similar impact as that of a car at a speed of 64 hits another stationary car.

Correct me if I'm wrong.

This is correct. Rear-end crashes are not tested beyond the effect of whiplash injuries. One of the major reason is the inertia, the rear-ended car always moves forward. When my car was rear-ended, it moved close to 20 ft after it got hit. The structure that is designed for frontal impact is extended to rear of the car too. So the effect is quite similar.

Regarding whiplash, it is very important that one wears seat belt as well as adjust the seat properly. The seat is not just a chair to sit !! Car OEMs spend significant resource on designing a seat that absorbs the impact and hence seats that do not align to driver's posture is practically useless during rear collision.

Originally Posted by Thumping Soul

A
But could you also explain a bit more on the role played by structural rigidity of a car and the side impact bars in case of side impacts. How do cars with curtain airbags fare against the ones without it. This becomes more important from the point that typically kids are seated close to the windows, even in case of cars with child seats.

The effect of side structural integrity is evaluated during the side impact tests. It is one of the most important tests as side impact collision is the cause of second most fatalities and injuries. What this test evaluates are few things. It ensures that there is adequate protection of the critical body regions for both front seat and rear seat passengers.
The need to pass this test has driven the strength of structures of vehicles around the B-pillar (between the doors), the fitment of side impact or curtain airbags in cars but also the development of less obvious energy-absorbing structures in seats and door panels.
The energy absorption of the seat and door panels are important as in most partial overlap T-bone accident (side impact), the impact is borne by these structures and the passenger is practically saved by the side impact airbags. I will share some pictures of a side impact crash and the deployment of the airbags later. The timing and deployment of airbags must be very carefully controlled to ensure that they provide the greatest protection possible.
One way to read this test result is to check the occupant compartment intrusion data. This is how much the impact penetrates inside the driver's seating position by measuring the movement of B-pillar to longitudinal centerline of driver's seat. Smaller the number safer is the car, so -26 cm is better than -22 cm etc. To get the data click on Side Impact and then click on the Test Measurement data.

Euro-NCAP does not publish this data in a readable format but one can check the tests done by IIHS in USA.
For reference here are few data points
http://www.iihs.org/iihs/ratings/veh...k-4-door-wagon
http://www.iihs.org/iihs/ratings/veh...c90-4-door-suv

Originally Posted by alpha1

Hi acurafan, this is a magnificent thread.
I had a question:
What is the basis for deciding that two opposing vehicles at 50 kmph represents useful case.

Typically the full highway speed crash is quite rare in most developing countries due to the presence of divided highways, better road surface as well as guard rails that protect the car from crashing in to the surrounding. The speed that Euro NCAP uses is the most frequently encountered speeds as per the various accident databases such as GiDAS etc. Most fatal accidents actually happen at 40 kmph or below.

Originally Posted by Turbohead

Any idea how many cars are used up for testing? Do manufacturers take back the tested cars for R&D?

This is easy, up to 4 based on how many tests the car aces
No the cars are scrapped after recovery of all meaningful data. One important point to mention is that the cars are bought anonymously, either from a single dealer or from several. Once the cars are at the test laboratory, the manufacturer is informed of the vehicle identification numbers (VINs) and are asked to confirm the specification

[Thad E Ginathom]

Originally Posted by acurafan

Regarding whiplash, it is very important that one wears seat belt as well as adjust the seat properly. The seat is not just a chair to sit !! Car OEMs spend significant resource on designing a seat that absorbs the impact and hence seats that do not align to driver's posture is practically useless during rear collision.

I think it is important to mention that the headrests are a vital part of this. Their primary purpose, as I understand it, is not to "rest" the head, but to help prevent whiplash.

My car is seldom occupied by more than two people. The rear view is rather obstructed by the rear headrests. I used to remove them, but recently my conscience is asking me how I would feel about one of my occasional passengers, possibly elderly, suffering a serious neck injury --- so they are back in place.

Most fatal accidents actually happen at 40 kmph or below.

And most people would find that hard to believe. One of the great myths of Indian driving is that "city speeds" are safe.

[acurafan]

Originally Posted by Thad E Ginathom

I think it is important to mention that the headrests are a vital part of this. Their primary purpose, as I understand it, is not to "rest" the head, but to help prevent whiplash.

And most people would find that hard to believe. One of the great myths of Indian driving is that "city speeds" are safe.

Yes, very true. Adjusting the seat, so that the back of the head touches the center of the headrest while driving should also be a safety check.
Volvo has the option of folding the rear headrest with touch of a buttopn to improve visibility when there are no rear seat passengers. It is such an obvious design choice and you wonder why no one does it !!

Yes, there are few myths about safety. Looking at these crash videos, I wonder how people can think they are safe at even 40-50 kmph collision is beyond me.
Another thing that bugs me is judging a car's structural safety by how well the door makes a thud or how thick the sheet metal covering the car frame is.
Unfortunately, even in the industry the designers have the last say on the vehicle design. It makes life very difficult for safety engineers to place the sensors that can improve the safety but will ruin the aesthetics.

[DaiusPitar]

Just came across this podcast. Personally I didn't realise the situation was that bad.

https://www.npr.org/sections/money/2...-trade-barrier

Mods, please merge this in case there is an alternative thread on the same.