I'm curious as to whether speed distronic + bas plus braking will ever stop you hitting something (as per the Volvo system).

As I understand the system, 200m is the detection limit, and 0.4g (about 40% braking power) is the initial application 1.6 seconds before collision. At 0.6s, full braking is applied. It apparently applies to both stationary and moving objects, but not people, animals, approaching cars, or cross-traffic vehicles. (New S-class pre-safe extends function to pedestrians).

Mercedes said up to 30kmh can be washed off the speed if the driver doesn't do anything. The speed of operation is 7km to 200kmh.

Conclusion: at a closing speed of 30kmh+ the system will not prevent a collision if you ignore the warning. Correct?

Question: if you ignore the warning, is your accelerator input ignored, or does autonomous braking compete with the engine, reducing its effectiveness?

Next calculation (exercise for the reader).

What is the largest speed delta where a human heeding the 2.6s warning will avoid a collision by hitting the brake - permitting the system to apply full braking. Consider the ML takes 39 meters to stop from 100kmh, but maybe 150m from 200-0kmh. And consider reaction time to the alert. At 100kmh a 2.6 second warning to a brick wall is 72 meters left to go. At 200km, 2.6 seconds warning would be insufficient time even with instantaneous brake application.

Note that info on this system is quite variable because it has gone through iterations. Some resources say it isn't active below 30kmh, others say it does not react to stationary objects (apparently this got improved). I believe the current system reacts to stationary objects and is active from 7kmh.

Anyone willing to drive into a shopping wall car park at 20kmh to test it

Oh! last question, if you come up behind a truck on a straight empty two lane road with a 30kmh+ closing speed, approach without braking, then pull out to overtake fairly late, will the car apply autonomous braking? what about if the indicator is on?

 

Forget your mathematics - its a long time since I left High School.

Twenty years ago I was the third car in a four vehicle collision. I hit the 52 ton parked truck at exactly 100km/h. As a result I walk funny but I am here today, as is my wife who suffered a fractured vertabrae.

Perhaps if we had this new technology, we might have hit at 90,80, maybe 50km/h. If so we would have been better off.

"They don't make cars like they used to, thank God for that!"

 

no quibble from me it is a virtual crumple zone

just curious to know how fast the closing speed has to be before auto braking would cause a hit..

 

I had an issue with my distronic not seeing vehicles in front. I took it in about 4 times for this issue. MB had their technical rep come look at the vehicle. He suggested I try it and see if the vehicle actually stops. I tole him to put his wife and kids in my car and try it since he had all the confidence in the world that it was working correctly. For some unknown reason he didn't want to do that. :-)

 

2014 ML and GL will have those same features that will be on the 2014 E class, so pedestrian detection is a given in MY14


the system is not designed to stop the vehicle hitting something 100% of the time, it is designed to reduce the impact OR stop the vehicle IF possible, again it is "IF" and "OR"

 

I agree with the IF and OR but it should work 100% of the time. After all, I paid 100% of the money for it.

 

I get where your coming from and I know you paid $$$ and I also paid over 100k for a GL and I have expectations as well but marketing and reality is two different things. You should count on it to lessen the impact not totally stop the vehicle. Forget what ever MB says ... it is all marketing hype, in the manual which is what you should go by it clearly says to reduce impact and IF possible stop the vehicle hitting another car.

 

Twice mine has bought me to a complete stop from 100km/h without touching the brake pedal ... I was blown away, so was my passenger.

First time was approaching roadworks on a country road where the traffic came to a complete stop. Second time was exiting a freeway where there's traffic lights at the end of the exit ramp.

It's not quite as smooth as doing it yourself, but a pretty cool feature if you ask me.

 

Love when you are highway cruising behind the stream of traffic, you come to a town and automatically slow down with the traffic.
Hate it when you're going slow through the town, and the car infront slows and turns off. Next thing you're on full power accelarating to 110km/h in the 50 zone.

 

Did you not touch the brake by personal choice? Bravery award!

 

Haha well I saw Jeremy Clarkson do it on Top Gear a couple of years ago in an S-Class. Check the following video out if you haven't seen it before, but head to the 2:00 mark if don't want to watch the whole thing Anyway, I still wasn't sure if my distronic was the same as what's in the S-Class.

However, I didn't try mine intentionally. The first time at the roadwork zone my foot was hovering over the pedal (same as Clarkson was in the above video) ready to apply the brakes myself but the car was slowing itself down quickly enough and I figured I might need to apply the brakes myself towards the end but no, it completely stopped me! At all times there was plenty of time and I was ready to apply the brakes myself if necessary.

My concern with this feature is this ... if you're travelling at highway speed and an incident occurs directly in front of you distronic will apply emergency braking but what if I want to swerve into another lane to go around the incident or to avoid being hit up the bum by a following vehicle (which hopefully isn't a huge truck!) I would need to react quite quickly and accelerate to cancel distronic's automatic braking.

This is the same for the Active Lane Keep assist (ALKA). I'm still getting used to this feature but a few times it has pulled my car back into the lane when I've got too close to the middle white line which is what it's supposed to do. Ok, so what if there's an obstacle on the side of the road (hopefuly not a pedestrian) that I'm trying to avoid and I move over slightly but ALKA pulls me back into the lane and I end up hitting so called obstacle. I asked the dealer about this and they said you just need to indicate and that will cancel the ALKA. That is fine in theory but sometimes these things happen very quickly especially if you're travelling at 100km/h and the last thing you think of when swerving to avoid something is to turn on the indicator. I heard of an incident when distronic was first introduced into MBs where a motorist was driving and an oncoming vehicle was over the middle line so he swerved off to the side of the road to avoid a head on collision but ALKA pulled the car back into the path of the oncoming vehicle. Once again when I told the dealer about this they said he should have indicated. So the system is not flawless it seems, and could possibly put you into a very dangerous situation.

Do I now need to drive around with my left hand poised on the indicator stalk ready to turn it on in the event of something like the above occurring? I'm actually considering turning all of these driver aids off as they do make me a little nervous.

 

Yes, so true, this has happened to me too. I'm getting used to it now and also realising it's not completely fool-proof and I need to seriously keep my mind on the job when using this feature.

 

I had the exact same concern as you and the sales rep walked me through it during the test drive.
If the AKLA tries to move the car to the center and you still try to steer it in what ever direction it will go with your input. I tried it in the 13 GL I drove back in October, the system will not override your input ( I did not use the turn signal)... It is not flawless though

 

Unfortunately your dealer should also have told you the ALKA will also cancel if you make a clear movement on the brake or accelerator, or steer against the correction procedure.

You are the driver and you still have the final say.

 

Oh i see, yes I've seen videos of distronic cruise control working so I'll be doing what others have done and watching as it keeps pace with the car ahead all the way down to zero ..

however I guess that is different than the chiming collision warning feature, and the 40% braking feature, followed by full braking in the last second. Which is active all the time - with or without cruise control on.

That is actually the feature I'm curious about. Not really from a safety perspective. Just curious about where its limits really are.

There is a video online at a mercedes driving school and an inflatable barrier, the instructor demonstrates the various different modes of operation. The last one - if you're asleep at the wheel and do not react - ends up with the car hitting the inflatable barrier. But the exact details are still not described, and may be outdated anyway I'm sure they keep improving the system.

 

Your 2012 ML is the same Distronic PLUS system as the 2007+ S Class.

First gen Distronic technology only applies max 30% braking and doesn't will only stop your car to 30mph before the drive must take over braking duties (hinted by a beep). This first gen Distronic was found on the W220 S, W215 CL, R230 SL, W211 E, W219 CLS, W164 ML, X164 GL, and W251 R.

The second gen Distronic PLUS is what's found on the newer generation of cars (and all successors of cars mentioned above except the S and CL). This is the system that will stop your car all the way to 0mph and apply all braking power if necessary.

The next gen S, CL, and facelifted E will get the third generation Distronic that will monitor cross traffic and I belive pedestrians as well.

 

I've had the distronic warning beeps many times as I rapidly approach a car before passing it or the car ahead is turning. I've never felt any braking from the system in these situations.