[DHABHAR.BEHRAM]

Originally Posted by Chewbacca

Regarding the BMW accident, is that section of the expressway curved?

Dear Chewbacca - hello to you. Yes, it is just at the end of a left turn with a large radius. It is also very slightly downwards facing so the car builds a lot of momentum. Maybe they can put some rumblers just before this spot.

Best regards,

Behram Dhabhar

[shubhodeepdas@g]

Originally Posted by itwasntme

Dispassionately looking at these pictures (no offence meant to anyone, RIP of course):

1. Looks like the driver was very very unlucky as the car probably aquaplaned at E-way speeds and immediately....why the front seat has been so badly pushed forward.

Just to add as number 4, most cars are tested for such a crash at 40 mph or 64 kmph. Beyond that all bets are off. It is mostly assumed that people sense impending danger and slow down within that above limit for crumple zones, airbags and seat belts to save them.

Its just a good practice to keep in mind at what speeds the car is rated 5 stars.

[arjithin]

Happened yesterday night at ECC road, Whitefield, Bangalore. Both the airbags deployed and passengers are said to be fine. SUV was overspeeding on a single lane road at a residential layout.

[1lokesh]

This BMW accident has shaken me completely. More so because I drove down from Mumbai to Goa via this place on the night of 9th Jul with my family. It was raining heavily and I could not help but pray for those in BMWs/Audis and Mercs speeding away at 120+ speeds at the worst estimates of mine since I was myself in the range of 90s.

There are perils on high speed carriageways especially when it's raining given that infrastructure in India is really pathetic. Had that concrete structure been made with a little curve, may be lost lives would have been saved.

IMHO, there is no way a head on collision like that will be of lesser damage when the vehicle in triple digit speed hits a concrete structure built like that to bring it to a sudden halt. Imagine from 100 (probably more) to 0 in fraction of a second. Unbelted passengers on rear seats will just add to the damage.

But then again, I somehow thought BMWs/Mercs/Audis were vault strong safe. That perception of mine is defeated.

RIP departed souls.

[silversteed]

Originally Posted by arjithin

Happened yesterday night at ECC road, Whitefield, Bangalore. Both the airbags deployed and passengers are said to be fine. SUV was overspeeding on a single lane road at a residential layout.

Too bad that (s)he doesn't know Jumbo Jets (747) can't land on airfields designed for ATRs

Jokes aside, wilful speeding inside residential layouts is a crime and the driver must be penalised. Sadly, (s)he will get away with a few thousands paid for the repair costs that do not get covered by Insurance.

[Santoshbhat]

Originally Posted by Chewbacca

Any buyers for the tyre burst theory?

Unlikely as BMWs ride on run flat tyres with reinforced sidewalls and are less prone to sudden tyre burst. Even if it bursts, with RFTs, the driver can keep things in control much better compared to normal tubeless.

Aquaplaning seems to be the most likely cause. I was wondering why ESP was not able keep the car from sliding out of control?

Dogs and stray animals are other dangers in wet and slippery conditions. Even at 80 or 90 kph any sudden steering or brake input can cause one to lose control.

[Akshay1234]

Originally Posted by BeingCynical

A young senior executive of Bajaj Auto along with his wife and two children was driving from Mumbai to Pune via expressway. Due to rain and slippery conditions, his BMW skidded out of the track and hit the median killing the executive and his wife on the spot and badly injuring his two kids.

Both kids are said to be critical but stable condition. May the departed souls rest in peace

Looking at the first pic, it seems as though the seatbelt was not being used. I may be wrong though.

Originally Posted by Chewbacca

Asking BMW owners and experts .... Is is conformed that BMW airbags will NOT deploy if front passengers are NOT belted?
Also, I see the headrest of front seat has touched the windscreen. It seems more likely that the paramedics moved the seat forward to extract the rear passengers.

Maybe at low speeds they will not deploy if people are not wearing the seatbelts. But at higher speeds like this crash, they will definitely deploy, seatbelts or no seatbelts.

Originally Posted by Santoshbhat

Aquaplaning seems to be the most likely cause. I was wondering why ESP was not able keep the car from sliding out of control?

But ESP can help keeps things in control only if the tyres have some amount of traction. In a case like this where the car is aquaplaning, the tyres are not touching the road at all so no question of ESP being able to help.

[Santoshbhat]

Originally Posted by akshay1234

But ESP can help keeps things in control only if the tyres have some amount of traction. In a case like this where the car is aquaplaning, the tyres are not touching the road at all so no question of ESP being able to help.

Agreed. So what is the best thing to do as a driver if you start aquaplaning on the highway? Do you hit the brakes hard and steer against the slide and hope that ABS will help regain traction and once traction is regained hope that ESP kicks in and keeps the car straight? This I think will be the natural reactions of any driver.

Another thing that's important is to never use cruise control when roads are wet. Are modern cars clever enough to cut power when they sense a slide with cruise control activated?

[Chewbacca]

Originally Posted by DHABHAR.BEHRAM

Yes, it is just at the end of a left turn with a large radius. It is also very slightly downwards facing so the car builds a lot of momentum. Maybe they can put some rumblers just before this spot.

Best regards,

Behram Dhabhar

I think this is the spot ...

Next time I will be extra careful on this bend, thank you!!

[SmartCat]

Originally Posted by Santoshbhat

Agreed. So what is the best thing to do as a driver if you start aquaplaning on the highway? Do you hit the brakes hard and steer against the slide and hope that ABS will help regain traction and once traction is regained hope that ESP kicks in and keeps the car straight? This I think will be the natural reactions of any driver.

Another thing that's important is to never use cruise control when roads are wet. Are modern cars clever enough to cut power when they sense a slide with cruise control activated?

It's a prevention better than cure type of situation. From what I know, it is quite impossible to recover an aquaplaning car for ordinary drivers. It's like your tyres are replaced by snow skis.

Perhaps NOT slamming the brakes and giving small steering inputs till you get control helps.

Prevention of aquaplaning would involve -

1) Drivng at speeds of around 80 kmph
2) Good tread depth
3) Extra cautiousness during "fresh rains" (thin sheet of water, oil, mud, grime)
4) Extra cautiousness on empty highways
5) Disabling cruise control

There is a school of thought that part-time 4x4 (AWD) which are mostly FWDs, but send power to rear when they detect slip, are more prone to aquaplaning. The logic is -

1) Front wheel lose traction
2) Power is suddenly sent to rear wheels
3) Vehicle oversteers because front has no grip and rear wheels are spinning vigorously
3) Vehicle loses directional stability

If the above logic makes sense (its debated around, but is not scientifically proven), could it be that an accelerating RWD car is more prone to aquaplaning than a FWD car? Powered rear wheels = vehicle oversteering = loss of directional stability?

[arjithin]

Originally Posted by akshay1234

Maybe at low speeds they will not deploy if people are not wearing the seatbelts. But at higher speeds like this crash, they will definitely deploy, seatbelts or no seatbelts.

Airbags are supplementary restraint systems (you always see SRS airbags). The primary defence is seat belt. An airbag opening up on a non belted up passenger can even harm the passenger and the effectiveness is totally unpredictable.

[Akshay1234]

Originally Posted by Santoshbhat

Agreed. So what is the best thing to do as a driver if you start aquaplaning on the highway? Do you hit the brakes hard and steer against the slide and hope that ABS will help regain traction and once traction is regained hope that ESP kicks in and keeps the car straight? This I think will be the natural reactions of any driver.

Another thing that's important is to never use cruise control when roads are wet. Are modern cars clever enough to cut power when they sense a slide with cruise control activated?

As far as I know if you aquaplane, its better to not hit the brake or make are steering movements as those may destabilize the car more. Its better to just wait for the car to cut through the water and regain traction (at which point it will be more stable if you don't slow down the wheels by hitting the brakes).

As mentioned by smartcat, its more of a prevention rather than cure thing.

Originally Posted by arjithin

Airbags are supplementary restraint systems (you always see SRS airbags). The primary defence is seat belt. An airbag opening up on a non belted up passenger can even harm the passenger and the effectiveness is totally unpredictable.

I agree. But if the person is foolish enough to not wear a seatbelt, and say there is a crash at 80kmph I think it might be better to hit an airbag than to hit a hard dashboard.

[arjithin]

Originally Posted by akshay1234

I agree. But if the person is foolish enough to not wear a seatbelt, and say there is a crash at 80kmph I think it might be better to hit an airbag than to hit a hard dashboard.

True, but the manufacturers view may be different on why should an airbag be deployed when there is no passenger on the seat??
Some of the rental cars I drove in USA had an indicator showing if passenger airbag is ON or OFF on the dashboard, and that system works based on 2 sensors ; 1. Seatbelt buckled or not, 2. Weight on the seat.
The indicator showed OFF when seatbelt was not used or when my 6 year old was in front seat with a booster and seatbelt buckled up.

Edit: if my memory is correct, there was a manual airbag override switch as well beside the indicator.

[itwasntme]

Originally Posted by Chewbacca

I think this is the spot ...

Next time I will be extra careful on this bend, thank you!!

That is truly a terrible obstruction RIGHT at the apex of that deceptively easy curve! In my humble opinion, MPEL should replace these deadly rectangular abutments / barriers with a simple ground-level slab of concrete to fully cover the underpass below.

I fail to see the rationale why they need to keep that section exposed. Is there any technical reason (apart from possibly lighting up the underpass with natural lighting), or is this simple antiquated design philosophy at work here?

[Thad E Ginathom]

Originally Posted by Santoshbhat

Agreed. So what is the best thing to do as a driver if you start aquaplaning on the highway? Do you hit the brakes hard and steer against the slide and hope that ABS will help regain traction and once traction is regained hope that ESP kicks in and keeps the car straight? This I think will be the natural reactions of any driver.

Another thing that's important is to never use cruise control when roads are wet. Are modern cars clever enough to cut power when they sense a slide with cruise control activated?

Originally Posted by akshay1234

As far as I know if you aquaplane, its better to not hit the brake or make are steering movements as those may destabilize the car more. Its better to just wait for the car to cut through the water and regain traction (at which point it will be more stable if you don't slow down the wheels by hitting the brakes). ... ... ...

I don't really know the "correct" answer, but in my instance, I seemed to remember "hands off everything." Of course, I don't mean hands off the wheel literally . But I did not attempt to steer or brake. I took my foot off the accelerator. This is easy to say when the car is going in a more or less straight line. Mine was.

Prevention is certainly better than cure. In fact the only possible excuse for aquaplaning is flash-flooding. There is no way we should be going that fast if there is any possibility of solid water on the road. How fast is That fast? I seem to remember being told 50MPH, so 80kph. And should be driving anything like that fast in heavy rain anyway? Probably not.