robl45

Been meaning to ask about the adaptive cruise control. I've read that it works great in stop and go traffic and can bring you to a complete stop which it does, sort of. With mine it will bring me to a complete stop, but half the time will slam me into the car in front of me if I don't intervene. I have it set at the furthest back following setting, but if cars are stopping it quickly, its like it doesn't brake in time. I've had it multiple times on the highway when cars stop quickly that it either stops 2 feet in back of the other car or starts flashing the red light on the dash and I have to intervene.

kart125

It happens to me if i change lane and there is a slower or stopped car in the new lane. The car accelerates like it does not see the new car. Quite disturbing the first time it hapens. Otherwise i find it useful. Wonder if a software update could solve this issue.

robl45

The switching lanes it happens, but this is just following another car, if they brake too fast, it won't stop

HKJay

I think it will stop even after it beeps and starts flashing red. It's just a matter of who has the ***** to find out. But you're right, the D+ doesn't read subtle cue's like the car in fronts' brake light coming on, and can't see ahead for slowing traffic. You do end up looking like a maniac if you just let it do it's thing. Like speed up into cars that have started to brake lightly. I haven't had anyone I know following me yet while using D+, but I wonder when it puts my brake lights on, or rather when it is actually braking. I figure some cars behind me have been wondering why I'm braking so far back behind the car in front. Otherwise, it is kind of nice to have in stop and go traffic, but I do wish that it would just get moving again by itself after coming to a stop, rather than me having to tap the gas.

robl45

I'm sure it will try to stop but when it's flashing red, in 10 feet behind the car. Just trying to figure if it's normal. Is like it's not braking hard enough to show me down. And shouldn't it be using the presafe brake at that point? I had the dealer check the presafe brake and they said its fine, but I tested a 2010 and saw presafe brake flash in the panel and never seen it on this car even when 5 feet from hitting a car.

kart125

I'm thinking of doing a test in a parking lot with cardboard boxes to see if it will brake...

xxGenericSNxx

This video may be of interest to you guys (jump to 3:40 for the W221 S-Class with Distronic Plus- same system in our W212 E):

Although they're not testing D+ they are testing the autonomous emergency braking feature in case you're about to rear end someone.

robl45

So basically the pre safe brake is a useless feature if it hits the car in front of you.

grimesch

I have tried to locate a relevant test (E350 or E63) for the last model, but haven't seen one that demonstrates the Pre-safe feature. This one is rather disturbing, but so far it is the only one that pokes holes in MB safety features.

robl45

I can't say I can argue with the video, I've watched my car many times come within 10 feet of a vehicle and the red light is flashing and beeping and yet it isn't braking. There is no way it is going to stop the car if it brakes at that time frame. According to MB website, it should be 2.6 seconds for warning, then 1.6 seconds is applies extra brake force if you hit the brakes, then .6 seconds it brakes. With mine its like 1 second when it starts warning. Obviously I don't plan to test crashing into someone to find out.

HPMan

I don't think this demonstrates any significant shortcoming. Obviously Volvo's system appears to be better (based upon the video), but who is really expecting the car to stop itself in an instant with at 25 mph speed differential? It still slowed the S-class down considerably. Distronic + has saved me a couple times in bumper-to-bumper traffic where I wasn't paying close enough attention to my surroundings, so I won't knock it too much. My $0.02.

kart125

All the hardware is there, it's the software calibration that needs to be readjsuted to make it more aggressive on the braking like Volvo's system. Come on MB you can do better!

robl45

Can anyone help me understand when theirs starts to warn them. Mine is like 10 feet away from the car in front of me. Do you see anything on the instrument cluster like pre safe brake or any indication that the car is braking on its own? I'm trying to figure out if I need to take the car back in again. I told them I didn't think the presafe brake was working and they said its working correctly. Even when using the cruise control in stop and go traffic, its like a rollercoaster ride every time guessing whether it will actually stop in time.

screw991le

From what understand it is not just distance. It factors in speed and distance, the system has a formula in which it thinks your not going to stop in enough time. I have never tried to let it go on its own. But mine will only work if I apply the brakes first. It will take over in applying more pressure to the pedal if it thinks I have not applied enough pressure to stop the car before I hit something. Mine will not apply any brakes if I have not started to brake first.

What year did this change that the driver does not need to touch the brakes, and the car will stop all on it own?

HKJay

I am. If volvo can do it, MB sure as hell better figure something out. No point of a system that kinda works. That video was really upsetting, especially how well the volvo system works in comparison.

HKJay

i forgot to post this but last week early in the morning I was using D+ and the steering function. It was 4 in the morning, so no one on the highway. Through a very gentle left bend I decided to let the car do it's thing. I applied only enough pressure on the wheel that the system still worked. In the middle lane it lagged in turning until almost out of the right side of the lane then held it's line decently through the bend. But on the exit, the car shot straight into the left lane before I corrected. I don't use this function all that much, but every now and then I give it another shot. It always disappoints. I'm ok with that if this is just how it is. But if there is something wrong with mine in particular, I'd like to get it fixed.

ace10

I "play" with this system quite often.

Right now, our local roads are in terrible shape, in terms of lane markers and boundaries being visible. From the wear of the snow blades, brine residue and sand/gravel. The system hates not being able to "see" very clearly marked boundaries. No question about it. It also seems to help if I keep the grill and windshield clean.

Same goes for wet roads. The car cannot "see" the makers nearly as well.

In true stop and go traffic, the system is worth its weight in gold. Performs perfectly.

And yeah, it's kinda fun to let the car steer and operate the pedals every now and then while at speed, but obviously, I (or anyone) wouldn't rely on it to get you from point A to point B on a given road.

Another area where the system really get frazzled is when traveling in right lane and there is an on or offramp. The system tries to split the differnce between the increasing lane (which is obviously not proper).