Well not ever knowingly experienced this until this morning, never driven a truck with it on until now.
Coming up windy hill east bound (M62) not at max load but still heavy, catching up with a heavy, i was going to pull out to overtake but no my truck slowed to match his speed, so left it to do what it wanted to do, with my right foot covering the brake just in case, wouldn’t trust it to be honest.
Was quite surprised on how well it worked it worked even down the dips and the long run down the other side where you would normally be check braking to keep the speed down, but no it just did it all this it’s self, even when another truck came in between us just before the M621 junction there was no drama, just slowed a bit to open the gap and carried on, I would give it a 9/10 for distance control.
I’m not a real fan of any cruise control, and certainly wouldnt be dictated to about its use, I use it when I think it’s safe to use, I have heard of some companies that dictate maximum use at all times, not for me.
I would may be use this ACC more though if I could adjust the minimum distance from the truck in front as at low speed it’s to close for my liking.
So if any one knows if you can adjust this distance let me know, it’s a 67 plate actros I think, not up on merc trucks, if not I will carry on using me right foot.
I have it on my car, the ACC took some getting used to but it is great for when crawling along in rush hour traffic, just make sure you set the safe distance up and the thing will crawl along and apply the brakes as required then release them and repeat as the traffic moves & stops. Just be careful using it as you approach roundabouts because it works using the signal bounced off the vehicle in front, and if the vehicle has moved off it’s gonna try to pull out. My 1st experience of using the ACC was heading along the A46 to Newark, it’s a strange test of confidence when you have the CC set at 70 and then it slows down to a crawl without having to touch the brake pedal, then it set off again all I did was turn the steering wheel
Problem is your trundling along at 56mph then approach another truck doing 52mph… daydreaming then realise you’ve done the last 10 mile at 52mph [emoji23]
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When you’re following another truck downhill using ACC, why aren’t you catching up with it?
Is the truck using engine braking and gears, or is it using service brakes?
Actros, I don’t know about, but if you rely on ACC a DAF will cook up your brakes if you let it.
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Edit. Using the hill descent, should use engine and gears rather than brakes.
Wait until its snowing or sleet, the sensor gets blocked & stands on the brakes as it thinks your about to rear end something , happened to me going s/b on the M1 jct 19 last year. The truck behind swerved to avoid me & when he saw that I’d done an emergency break for nothing gave me some interesting sign language.
Also it has a nasty habit of doing the same thing when you’re going around a bend on a dual carriageway, if you’re truck is going into the curve but the vehicle in the other lane is going slower in the bend on the other lane the sensor thinks your going to hit & makes you head but the windscreen. Autonomous vehicles are a long way off.
I’ve had Scania’s throw a wobbly when the sensor gets covered in snow, they do it when it’s raining too. The dashboard lights up like a Christmas tree
LisasGuy:
Wait until its snowing or sleet, the sensor gets blocked & stands on the brakes as it thinks your about to rear end something , happened to me going s/b on the M1 jct 19 last year. The truck behind swerved to avoid me & when he saw that I’d done an emergency break for nothing gave me some interesting sign language.
Also it has a nasty habit of doing the same thing when you’re going around a bend on a dual carriageway, if you’re truck is going into the curve but the vehicle in the other lane is going slower in the bend on the other lane the sensor thinks your going to hit & makes you head but the windscreen. Autonomous vehicles are a long way off.
The Scania I drove with auto brakes had a pre warning before the truck would take over and brake, you had to touch the brake or throttle to override the system, did you miss that pre warning? I can’t see any other truck make will not have a pre warning before slamming the brakes on.
Try reading the vehicle manual to find out what you need to do at pre-warning.
Franglais:
When you’re following another truck downhill using ACC, why aren’t you catching up with it?
Is the truck using engine braking and gears, or is it using service brakes?
Actros, I don’t know about, but if you rely on ACC a DAF will cook up your brakes if you let it.
.
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Edit. Using the hill descent, should use engine and gears rather than brakes.
I think it must be using service brakes with the exhaust brake as in the past dropping down windy hill always required some check braking to keep the speed down, so I imagine it was, I’ll find out tonight on my way back from Stoke tonight.
I did need to check brake dropping down the other side going west off acc.
mark1284:
Problem is your trundling along at 56mph then approach another truck doing 52mph… daydreaming then realise you’ve done the last 10 mile at 52mph [emoji23]Sent from my iPhone using Tapatalk
Being paid by the hour, I would never lose any sleep about sitting at 52, last weeks truck was only doing 53mph flat out, GPS, even though the speedo was saying 56mph.
weeto:
Franglais:
When you’re following another truck downhill using ACC, why aren’t you catching up with it?
Is the truck using engine braking and gears, or is it using service brakes?
Actros, I don’t know about, but if you rely on ACC a DAF will cook up your brakes if you let it.
.
.
Edit. Using the hill descent, should use engine and gears rather than brakes.I think it must be using service brakes with the exhaust brake as in the past dropping down windy hill always required some check braking to keep the speed down, so I imagine it was, I’ll find out tonight on my way back from Stoke tonight.
I did need to check brake dropping down the other side going west off acc.
Just be aware that on a long descent, if you rely on ACC and service brskes, rather than engine and gears, your brakes will be well cooked. If you’re not running heavy, nor on a steep long drag, it’s no problem, but be aware of what the vehicle is doing.
weeto:
LisasGuy:
Wait until its snowing or sleet, the sensor gets blocked & stands on the brakes as it thinks your about to rear end something , happened to me going s/b on the M1 jct 19 last year. The truck behind swerved to avoid me & when he saw that I’d done an emergency break for nothing gave me some interesting sign language.
Also it has a nasty habit of doing the same thing when you’re going around a bend on a dual carriageway, if you’re truck is going into the curve but the vehicle in the other lane is going slower in the bend on the other lane the sensor thinks your going to hit & makes you head but the windscreen. Autonomous vehicles are a long way off.The Scania I drove with auto brakes had a pre warning before the truck would take over and brake, you had to touch the brake or throttle to override the system, did you miss that pre warning? I can’t see any other truck make will not have a pre warning before slamming the brakes on.
Try reading the vehicle manual to find out what you need to do at pre-warning.
Nah the Mercs we have just hits the break lights up like a Xmas tree & has an audible warning all at the same time, we all switch the autonomous stuff off before we leave. Manuals are all taken out before we get to drive them along with any other bits that aren’t screwed down just incase we pinch them & flog them at a car boot
I LOVE ACC! Such a great gadget. Use it as much as I can when fitted. Never known brakes to be cooked though, but then it’s hard to cook brakes in a modern lorry anyhow these days, not like days of yore! You can adjust minimum distance in ones I’ve driven but couldn’t tell you how to do it in a MB. A truck with at least 500bhp, a decent auto box and ACC is pretty much my dream lorry. Works brilliantly in heavy traffic that’s moving fast enough to stop it deactivating too
It’s just a gimmick for the youngsters and steering wheel attendants that haven’t got a clue how to drive properly so need a computer to do it all for them. Proper drivers have good anticipation and know how to drive. No need for all these silly gimmicks. They’re more of a hindrance than a help.
mark1284:
Problem is your trundling along at 56mph then approach another truck doing 52mph… daydreaming then realise you’ve done the last 10 mile at 52mph [emoji23]
Why is this a problem? That 10 miles will have taken 50 seconds longer at 52mph than it would at 56mph. Or from another viewpoint, if hourly paid it will have earned you another 20p or so (exact figure depends on hourly rate, of course) so if you managed the same feat a couple of times a day every day you would have earned nearly enough to buy yourself a frothy coffee by the end of the week!
R420:
It’s just a gimmick for the youngsters and steering wheel attendants that haven’t got a clue how to drive properly so need a computer to do it all for them. Proper drivers have good anticipation and know how to drive. No need for all these silly gimmicks. They’re more of a hindrance than a help.
Up there with auto boxes, some are a god send for us old timers, after 32 driving all sorts I would never knock an auto, in fact I wouldn’t drive anything with a manual box, to many RSIs, left shoulder left hip, left knee, right foot to name a few, all down to driving “proper” trucks, wouldn’t wish that on anyone.
And anything that stops muppets from rear ending another truck on a straight motorway is also a good thing.
LisasGuy:
Wait until its snowing or sleet, the sensor gets blocked & stands on the brakes as it thinks your about to rear end something , happened to me going s/b on the M1 jct 19 last year. The truck behind swerved to avoid me & when he saw that I’d done an emergency break for nothing gave me some interesting sign language.
Also it has a nasty habit of doing the same thing when you’re going around a bend on a dual carriageway, if you’re truck is going into the curve but the vehicle in the other lane is going slower in the bend on the other lane the sensor thinks your going to hit & makes you head but the windscreen. Autonomous vehicles are a long way off.
You shouldn’t be using any type of cruise control when it’s sleeting or snowing , icy conditions . Any sort of wheel spin detected by a speed sensor and the computers take over which can end up in all sorts or pain , just saying 
R420:
It’s just a gimmick for the youngsters and steering wheel attendants that haven’t got a clue how to drive properly so need a computer to do it all for them. Proper drivers have good anticipation and know how to drive. No need for all these silly gimmicks. They’re more of a hindrance than a help.
OK old timer
weeto:
R420:
It’s just a gimmick for the youngsters and steering wheel attendants that haven’t got a clue how to drive properly so need a computer to do it all for them. Proper drivers have good anticipation and know how to drive. No need for all these silly gimmicks. They’re more of a hindrance than a help.Up there with auto boxes, some are a god send for us old timers, after 32 driving all sorts I would never knock an auto, in fact I wouldn’t drive anything with a manual box, to many RSIs, left shoulder left hip, left knee, right foot to name a few, all down to driving “proper” trucks, wouldn’t wish that on anyone.
And anything that stops muppets from rear ending another truck on a straight motorway is also a good thing.
Autos are fine on most trucks now, but how long did it take to get them to a point where they were pleasant to drive and actually made the job easier than doing it yourself with a stick? 20 years? The I-shfit became the benchmark when it was released, but still had its foibles and still does. Turning left or right out of a narrow junction with a heavy trailer and on a bit of an incline will quickly confuse it as it tries to block change up about 3 gears, just as your trailer wheels dig in on the turn and wash off the small amount of speed you’d built up, so you end up sat there in the middle of the road as it tries to find 2nd or 3rd to do it all again. You don’t have that problem in a 12 speed manual as you’d either hold it in gear until you were straightening up or just quickly split it up 1 gear instead of 3.
I’m not anti-technology but it has to work right, from the start, not some half-baked set-up that only works when it’s dry, sunny and no wind/rain/snow/leaves to confuse the sensors and dish out annoying false positives. Autos have come on a long way. The early ones were terrible with glacial change speeds (still bad on DAFs and Iveco) but our 450 XT Scanias are near instant and a pleasure to drive. They might even be dual clutch but just guessing here. Our older ones are still manual 4 over 4 with no splits and need working hard with 20,000 litres in the back with a 340 engine 
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ACC has a lonnnnnnnnng way to go before it works properly. The numerous issues mentioned up thread are all good examples of its failings.
Absolute garbage.
I don’t want to tag on to the vehicle in front.
If I’m gaining at 53…I know that knocking it up to 56 will get me swiftly past.
Don’t want to be continually glancing at the dash wondering if I have enough speed advantage or not.
And mine slapped the brakes on the other day,whilst overtaking a tractor.
Mercedes still hav’nt mastered radio reception or a gearbox.
So fork knows what made them have a go at acc
And the automatic windscreen wipers are useless.