[ecenandu]

https://www.youtube.com/watch?v=SNxjYLwhUng

The car rolls down a slope in to a busy main road, misses cars, bikes, pedestrians by a whisker. After missing them all, it then comes to a complete stop and then decides to move forward, climbs back up the slope, stops and then roll backwards. Luckily, before repeating the earlier routine by the car, some passerby intervene and stops the car.

The title of the video is quite funny, loosely translated, "People in Kerala who doesn't believe in ghost should watch this CCTV footage."

We can debunk the ghost hypothesis quite easily, well, if it was a ghost, he/she/it has done a brilliant job to miss all those vehicles. Must have been an excellent driver in the past life. .

All jokes aside, here is my hypothesis. The vehicle is AMT equipped one. The driver leaves the car in 'Drive'(D - AMT) and steps out, without switching off the vehicle. The vehicle rolls down the slope as the creep function in the AMT will not work as Hill Hold Assist(HHA). When the vehicle came to a level road, the creep function kicks in and makes the vehicle move forward.

I have only driven an AMT equipped vehicle myself a few times. So, I cannot guarantee whatever I said above is correct. That is the exact reason to post this here, to have a discussion.

Well, a bizarre event, luckily no one got injured.

[get2bid]

Originally Posted by ecenandu

..The driver leaves the car in 'Drive'(D - AMT) and steps out, without switching off the vehicle.

Wouldn't the driver notice the car moving as soon as he steps out of the car leaving the car in the 'Drive' mode? Especially if the car is still on, this would have been noticed almost immediately.

Really fortunate that no one was injured.

[ecenandu]

Originally Posted by get2bid

Especially if the car is still on, this would have been noticed almost immediately.

Well, that is my hypothesis. If there is a slight incline, the creep function might work as hill hold assist. It is a new car, it is likely that the driver forgot to notice the car is still switched on. I, myself has tried to crank the car few times even though the car was on, during the initial ownership period of our Honda City.

[condor]

Originally Posted by ecenandu

All jokes aside, here is my hypothesis. The vehicle is AMT equipped one.

That's a WagonR. Possible, but does the clip or any other report in media say it is an AMT ? But one thing that would support your hypothesis is that the initial roll-back speed is steadier, but later picks up.

It could have happened with any car on a slope, with the car in neutral and hand brake not engaged.

[Rajeevraj]

Companies are spending billion to develop self driving cars. Looks like this car from 'Gods own Country' has already mastered the art of self driving in Indian conditions.

I am of the opinion that the driver left it in D and put the hand brake on. The hand brake may not hold the car if left in D mode. Important to move to P in an AT car.

For my Vento TSI DSG, on a slope even if I engage hand brake and still leave it in D-It is going to roll.

Edit: Just realized we are not sure if it is an AMT car. I assume it may be.

[ecenandu]

Originally Posted by condor

It could have happened with any car on a slope, with the car in neutral and hand brake not engaged.

True. On a closer look, the road looks like it is a heavily banked one. So, it could very well be a car rolling down in neutral. Looks like a damped oscillation, right, the car moving up and down the slope.

The road might have a steeper banking, we can't make out properly because of the wide angle lens of the CCTV camera.

[Avalanche2409]

Whoa!! Talk about luck here. What are the odds that you set your car free to roll down on to the road like this and no one gets hurt?

If this is not an AMT, how on the earth can someone forget to engage their handbrake on a slope this steep? I for one have this paranoia of pulling the handbrake even on a flat surface.

[get2bid]

Originally Posted by ecenandu

.. It is a new car, it is likely that the driver forgot to notice the car is still switched on.

But, as soon as the driver takes his foot off the brake pedal, the car would start moving immediately. In fact, it would nearly be impossible for the driver to get down since the car would start moving as soon as the brake pedal is depressed.

What you are saying might hold true if the car is already on an incline climbing Up and the driver leaves it in Drive (D) mode and then gets down. in which case, the creep function would behave like the Hild Hold Assist and prevent the car from moving.

But again, this is what I am thinking.

[giri1.8]

Kerala being hilly region, I guess the other end of the road is an incline too, but somewhat less steeper than the parking.

car comes back in a way a marble would do when you roll it down a 'u' shaped surface, just normal physics in action IMO, this highlights the problem of lack of training for new drivers!

Hope he avoids such mistakes and gets to keep the car for a very long time, we all do mistakes, but this one could have easily taken a life.

[GeneralJazz]

Originally Posted by get2bid

Wouldn't the driver notice the car moving as soon as he steps out of the car leaving the car in the 'Drive' mode? Especially if the car is still on, this would have been noticed almost immediately.

Really fortunate that no one was injured.

The video starts with the car already rolling. This may have something to do with the AMT. I'll explain that below.

Originally Posted by Rajeevraj

I am of the opinion that the driver left it in D and put the hand brake on. The hand brake may not hold the car if left in D mode. Important to move to P in an AT car.

For my Vento TSI DSG, on a slope even if I engage hand brake and still leave it in D-It is going to roll.

Edit: Just realized we are not sure if it is an AMT car. I assume it may be.

Check out the auto gear shift here:
https://www.marutisuzuki.com/channel...chbacks/wagonr

Its an AMT. There is no P.

Originally Posted by ecenandu

True. On a closer look, the road looks like it is a heavily banked one. So, it could very well be a car rolling down in neutral. Looks like a damped oscillation, right, the car moving up and down the slope.

The road might have a steeper banking, we can't make out properly because of the wide angle lens of the CCTV camera.

Its not an oscillation. There is a 1-2 second gap after the car stops rolling in reverse before it starts moving forward. Thats the time it takes for the AMT to kick in.

Originally Posted by get2bid

But, as soon as the driver takes his foot off the brake pedal, the car would start moving immediately. In fact, it would nearly be impossible for the driver to get down since the car would start moving as soon as the brake pedal is depressed.

What you are saying might hold true if the car is already on an incline climbing Up and the driver leaves it in Drive (D) mode and then gets down. in which case, the creep function would behave like the Hild Hold Assist and prevent the car from moving.

But again, this is what I am thinking.

There is no hill hold in this AMT.

I have experienced something like this some time back. I have extensively driven both A-Star AT and Celerio AMT. The A-Star is ours and it was my first experience on an automatic. It doesn't have a hill hold feature but it has a creep function. This creep function will fight against the incline to a degree. Kind of like how we can control the movement on a MT with 1/2~1/4 clutch. It will creep ahead on small inclines while it will roll (or creep) back slowly on steeper ones.

I was expecting something like this when I first drove my uncle's AMT Celerio. But here's the difference. The car will 'creep' on flat roads even on small inclines till the speed is nearly 0 kmph. It then shifts to neutral, even when the gear is in 'D'. The thing is, once it shifts to neutral, it starts rolling back freely (or forwards if its a reverse incline/gear is in 'R'). It keeps rolling back till it comes to a stop, after which the AMT kicks in again and the vehicle moves forward. It can be clearly seen from the video that there is a 1-2 second gap between when the car stops and changes direction.

This happened to me on an elevated railway crossing. I was expecting the Celerio to either hold or creep back slowly. It actually shifted to neutral rolled back freely. By the time I hit the braked and stopped it, it again shifted to 'D' and started trying to move forwards. Failed to do that and shifted to neutral again.

This is what I think happens to the car in the video.

[blackwasp]

Originally Posted by ecenandu

All jokes aside, here is my hypothesis. The vehicle is AMT equipped one. The driver leaves the car in 'Drive'(D - AMT) and steps out, without switching off the vehicle. The vehicle rolls down the slope as the creep function in the AMT will not work as Hill Hold Assist(HHA). When the vehicle came to a level road, the creep function kicks in and makes the vehicle move forward.

Your theory is spot on. However there is a slight difference. This is how the events could have transpired -
1. Its a new car, and possibly an AMT one (the mirrors giveaway that its a Vxi and AMT comes in Vxi trim). The driver drives the car up the slope and releases the throttle and brakes to a stop. Upon releasing the brake, the car doesn't roll back immediately as the GB detects this as a traffic situation as tries to engage the clutch to creep forward. Engine is kept on (either forgotten or the driver is hoping to get going soon).

2. By sheer coincidence, the slope of the road/parking is just about sufficient to counter the forward motion of the car (like half clutch in MT). The driver gets a false sense of the car being securely parked and exits the vehicle as he doesn't see it rolling back.

3. This clutch slippage gets too much (heat?) and the AMT unit disengages the clutch, causing the car to roll back. Once it becomes stationary, the clutch is engaged and the car moves forward till resistance is met in the form of the slope.

4. Above is repeated, however, the distance the car moves is progressively reduced after each forward-backward movement.

5. A samaritan jumps in and probably engages the handbrake / switches off the car.

Originally Posted by get2bid

But, as soon as the driver takes his foot off the brake pedal, the car would start moving immediately.

See point no 2 above. I'm quoting myself from an older thread on the same below:

Originally Posted by blackwasp

I would advise against ATs that are AMT based. They will simply slip the clutch and the car will roll back on hill starts, if the handbrake is not used.

One big drawback of the AMTs is that its still a normal MT transmission which is controlled by a computer. It is programmed to disengage the clutch if it meets a bit too much resistance. This is also the reason for AMT problems in the 1000cc cars of MSIL. The bigger engines mask this to some extent by the higher power and torque numbers. But IMHO, AMTs should strictly be kept away from novice drivers / non car enthusiasts as the common man will rarely deep dive into the workings of the machine he's driving. Simple fact that the driver didn't engage the handbrake means that he has learned to use it only in a situation when the car is moving when parked and not as a safety precaution on slopes.

[bhavik.1991]

If the car is AMT & equipped with HHA.

1. Driver drives the car to the parking spot & lifts right foot of the accelerator.
2. HHA kicks in & applies break so the car doesn't move.
3. While HHA is holding the car, driver gets out of the car & closes the door.
4. HHA reaches cut-off time (usually 3-5 seconds) & disengages breaks.
5. While AMT tries to crawl the car, gravity force is greater & car starts to roll down.
6. Once the car reaches the flat surfaces, AMT starts to overpower gravity & moves the car forward.

PS: I haven't watched the video as youtube is restricted on my network. I have concluded the events with the help of previous comments.

[AtheK]

Wow that was really really close, reminds me of when i got my Vento TSI. I went to the accessory shop and as a habit(From driving manual) just walked out of the car, with the Gear still in D mode (Thinking it is in N). The moment i got out the car started moving towards the road, and we had to run and stop it before it hit the footpath. I got lucky that day since that road was not too crowded. Have been extra careful from that time.

The shopkeeper asked me after we got it back in control "Saar your own car or did you steal it"

This could have turned real nasty too, it missed a couple of autos just by a whisker, and it almost continued for a minute. Owner would have been in real soup, had it hit some other vehicle.

[knightrider_7]

Originally Posted by blackwasp

Your theory is spot on. However there is a slight difference. This is how the events could have transpired -

Simple fact that the driver didn't engage the handbrake means that he has learned to use it only in a situation when the car is moving when parked and not as a safety precaution on slopes.

I have driven my cousin's Wagon R AMT last week, and I agree with this explanation. Unless there is accelerator input/parking brake engaged while the car is on an incline, it will surely roll back as seen in the video. The creep function would work only if the incline is minor/road is flat.

[Abhinav6683]

I have been driving a Civic AT for 10 years.
If the driver left it in D then the key won't come out of the lock. The key comes out only in P mode. If he didn't lock the car and stepped out, the car would have moved back instantly and we would have seen him running after the car itself.
If the D mode of the car was powerful enough to drive it back up then it would hold the car in position. Must be a kid driver in the seat or trick video.