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Old 27th January 2020, 01:15   #30241
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Originally Posted by guru_max View Post
5 Killed in an accident near Dindigul as a car flies over the divider and hits a vehicle in the opposite direction. The man on the cycle also seems to be dead. as per the news report, the 4 other people who died are from the same family. But it's unclear which car they were traveling in from the report.
What kind of utter moron must he be to drive like that? Since he survived, he should absolutely be behind bars for this.

Last edited by navin : 28th January 2020 at 14:13. Reason: typo
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Old 27th January 2020, 06:34   #30242
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The time and place of this accident are not known. The CCTV footage shows a very lucky escape for the 2 bikers who almost got sandwiched between 2 vehicles. This video highlights the importance of safe distance when riding or driving on the road.

From the Kallada bus, it looks like this is South India, probably Tamilnadu. The vehicles start slowing abruptly and the mini pile up happens.
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Old 27th January 2020, 09:28   #30243
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Originally Posted by BenjiRoss View Post
The time and place of this accident are not known. The CCTV footage shows a very lucky escape for the 2 bikers who almost got sandwiched between 2 vehicles. This video highlights the importance of safe distance when riding or driving on the road.

All vehicles have braked hard, and bikers have at first barely managed to not hit the truck in front.

When hit by the second truck, the first truck driver has lifted his foot of the brakes thereby getting pushed ahead and saved the bikers.
Due to this the truck ahead must have probably hit another truck which was ahead of him.


Rahul

Last edited by suhaas307 : 6th February 2020 at 15:46. Reason: Spacing
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Old 27th January 2020, 11:11   #30244
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Originally Posted by guru_max View Post
5 Killed in an accident near Dindigul as a car flies over the divider and hits a vehicle in the opposite direction...
At 0:16 in the video the car is already out of control and a bit on the left of the Cyclist. At 0:17 he manages to hit the cyclist, at these speeds with almost all wheels on the dirt, the car will have little or no control. At 0:18 he jumps the divider, this is probably a correction made to move to the right but overcompensating due to the added grip on the right wheels. At 0:19 he manages to hit the swift Dzire.

I would assume the car went out of control before it even entered the frame trying to overtake the other two cars that stop shortly after the accident. The reason is "not knowing the limits of your car".

It is just sad to see the passengers in the other car suffer. RIP.

Many would say that the car was over speeding (which it was), but this can easily be a likely scenario at 70-80 kph in 5th gear, in the hands of any driver hitting sand, snow or water on one side of a car without stability control.
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Old 27th January 2020, 11:31   #30245
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Originally Posted by shubhodeepdas@g View Post
At 0:16 in the video the car is already out of control and a bit on the left of the Cyclist. At 0:17 he manages to hit the cyclist, at these speeds with almost all wheels on the dirt, the car will have little or no control. At 0:18 he jumps the divider, this is probably a correction made to move to the right but overcompensating due to the added grip on the right wheels. At 0:19 he manages to hit the swift Dzire.
Excellent analysis. It's scary to think that the entire accident happened within the time it took to read you post, with barely 1 second when the car could no longer be controlled.
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Old 27th January 2020, 11:52   #30246
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Originally Posted by shubhodeepdas@g View Post
Many would say that the car was over speeding (which it was), but this can easily be a likely scenario at 70-80 kph in 5th gear, in the hands of any driver hitting sand, snow or water on one side of a car without stability control.
I'm glad you brought up the gear aspect. I recall asking why one has better traction and steering control if one downshifts. I received a wonderful piece of insight from our forum members - engine braking kicks in when you downshift, thus transferring weight to the front of the car, thereby making the steering wheel feel more alive/responsive in your hands.

I had first experienced the positive effects of downshifting in the 'NFS-Porsche edition' video game (for which the EA game designers won awards for physics and realism). Later on in life, I'd used the downshifting strategy in ice and snow in the North-Eastern US to have an uneventful and safe 4.5 years over there. But I only fully understood the physics behind it last year on this forum!
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Old 27th January 2020, 13:37   #30247
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Originally Posted by shubhodeepdas@g View Post
"not knowing the limits of your car".
I belong to the same category, looks like what we see is half the picture. The car was definitely out of control even before entering the frame itself. There was easily enough space between the lorry and the cyclist to easily pass even a force traveler (A state transport guy would overtake a truck with his bus through that space).

The Etios went all the way to left, into the sand/dust and then turned back on the road. It clearly indicates that something happened before the Etios entered the frame which caused the driver to give a high steering input - and then correct the same with another one, and finally losing to the physics.
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Old 28th January 2020, 08:00   #30248
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Originally Posted by locusjag View Post
engine braking kicks in when you downshift, thus transferring weight to the front of the car, thereby making the steering wheel feel more alive/responsive in your hands.
Does it matter specially if its a FWD or a RWD? Or does it behave same in both the cases? The weight transfer I mean. Im thinking most of our FWD cars would be a little more benefitted, not sure though.
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Old 28th January 2020, 09:00   #30249
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Originally Posted by BenjiRoss View Post
The time and place of this accident are not known.
This is same as in post #26010 - https://www.team-bhp.com/forum/road-...ml#post4377650
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Old 28th January 2020, 10:07   #30250
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Even though the video is not available, it looks like it is definitely the same video. The discussion is quite useful in that page and the next 2 pages.
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Old 28th January 2020, 10:42   #30251
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Does it matter specially if its a FWD or a RWD? Or does it behave same in both the cases? The weight transfer I mean. Im thinking most of our FWD cars would be a little more benefitted, not sure though.
It's not about the weight shift but the traction available due to the input and output shaft RPMs to the gear box in higher gears. Most modern cars will have a 5th and 6th gear that are overdrives, which means the output shaft RPM will be higher than the input shaft. Some newer cars have a 4th gear that is overdrive as well working at a ratio of ~0.95.

Quote:
Putting this into the different gears in the modern car:
  • 1stgear The typical gear ratio here is 3.166:1. The RPM is usually at 947.
  • 2ndgear Gear ratio is at 1.882:1 with an RPM of 1,594
  • 3rdgear Gear ratio is 1.296:1 with an RPM of about 2,314
  • 4thgear Gear ratio is at 0.972:1 with an RPM of 3,086
  • 5thgear Gear ratio is 0.738:1 with an RPM of 4,065
Source. Note: This can differ from car to car but not by much.

This essentially means that the momentum of the car can drive the engine resulting in better fuel economy, and also means that the moment is usually more than the power the engine can deliver. This directly translates to the car being at the mercy of its own momentum and one way to recover the car is to drop it to lower gears step by step to gain back traction.

The above situation becomes a lot worse when the car is overloaded, more weight equals more momentum.

Coming to FWD and RWD, RWD would fair better in this situation as the front wheels just have to steer and not drive. The engine braking will be handled by the rear wheels. Coming to a 4WD or AWD system, things are more complicated based on their construction. They usually have far more engine braking at their disposal over their 2WD counterparts.

Last but not the least. Most of us are taught to press the clutch every time we brake, which is dangerous at higher speeds, as we loose out on whatever engine braking that we acquired by lifting off the throttle in first place. It should be used only when we have a risk of stalling the car.
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Old 28th January 2020, 12:21   #30252
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Quote:
Originally Posted by shubhodeepdas@g View Post
It's not about the weight shift but the traction available due to the input and output shaft RPMs to the gear box in higher gears.

This essentially means that the momentum of the car can drive the engine resulting in better fuel economy, and also means that the moment is usually more than the power the engine can deliver. This directly translates to the car being at the mercy of its own momentum and one way to recover the car is to drop it to lower gears step by step to gain back traction.
That a car would be at the mercy of its own momentum in higher gears is a wonderful point. I've never thought about it that way; it has to be for this same reason that one never coasts in neutral out on the highway. Being in neutral equates to a gear ratio of zero and allows for the worst possible maneuverability in a panic situation. Left in a straight line, you can very well coast in neutral but things won't end well if you suddenly need to change direction or brake.

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Old 28th January 2020, 12:55   #30253
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Originally Posted by locusjag View Post
That a car would be at the mercy of its own momentum in higher gears is a wonderful point. I've never thought about it that way; it has to be for this same reason that one never coasts in neutral out on the highway. Being in neutral equates to a gear ratio of zero and allows for the worst possible maneuverability in a panic situation. Left in a straight line, you can very well coast in neutral but things won't end well if you suddenly need to change direction or brake.

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Yeah, so its like not having control / manoeuvrability right? Same thing with depressing the clutch fully at higher speeds.
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Old 28th January 2020, 15:00   #30254
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Originally Posted by shubhodeepdas@g View Post

Last but not the least. Most of us are taught to press the clutch every time we brake, which is dangerous at higher speeds, as we loose out on whatever engine braking that we acquired by lifting off the throttle in first place. It should be used only when we have a risk of stalling the car.
Really?

I was taught that it's a huge no-no. You don't touch the clutch until the car is almost stopped and the engine would stall if you didn't.
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Old 28th January 2020, 16:28   #30255
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Report from TOI yesterday reads: Mumbai-Pune Expressway mishaps dipped 43 per cent over 4 years

Read more at:
http://timesofindia.indiatimes.com/a...campaign=cppst

So, how far we can rely on the data used for this analysis?

Have drivers really resorted to safe driving practices now or its just plain fluke that number of accidents have reduced?
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