I love the ACC in my Volvo - set the speed and distance to the car in front, and it does it all for you.
As I seem to be one of the few drivers who like to leave a 2 second gap to the car in front, that means that Audi drivers often think there's plenty of room to cut in front of me. This causes the ACC to reduce speed, to retore the clear distance in front of me. I assume that when the car brakes itself, the brake lights come on, but I have no way of knowing for sure. Can anyone conirm or deny this?
I've often wondered the same regarding the brakes - you'd hope so when it's actively braking.
It's not always clear when reducing speed with the ACC too, say from 70 to 50. I'll need to ask a passenger to have a look back when it's dark out and see if the brake lights are activated in various situations.
Lights come on in a Mercedes, you can also feel the brake pedal depress.Originally Posted by hogthrob
Couldn't say for sure in a Volvo but I'd hazard a guess it's the same.
The lights come on with ACC braking in BMWs too. It makes sense really, I can't see any implementation that brakes without the lights being safe or legal.
I too really rate ACC, with mine you can adjust the trailing distance if you are in an idiot rich environment but of course following too close yourself has its own complications.
My cruise control isn't adaptive, but I've often wondered if the brake lights come on when I reduce speed by toggling the switch. Regularly need to do this in 50mph average speed zones when some idiot is wavering between 40 and 50.
I suppose a way of checking is to try it on a dark road just after passing a reflective road sign facing for people going the other way.
Most basic CC systems have no brake interaction at all and just cut the throttle on hills, some do utilise the brakes AKA CC with brake but have no radar or camera tracking for adaptive. Those that do apply braking must surely use the lights I would think.
Adaptive cruise, brake lights, Yes.
Great system, i miss it for motorway driving and stop start driving.
Audi and BMW drivers love wee gaps.
I just wish people with any form of Cruise Control would actually use it, particularly on Motorways. I get fed up of modern cars which I know have CC fitted slowing down going up hills then speeding up when they go downhill! Are they brain dead or what?
Best Regards - Peter
I'd hate to be with you when you're on your own.
In my volvo can confirm the brake lights do come on when ACC actively brakes for me. I wouldn't be without ACC these days although I must confess I did worry a little when I first got a car with ACC versus just CC as I'd heard all the horror stories about cars slamming on the brakes for a crisp packet on the motorway etc.
I actually use mine more in town at slow speeds, whereas before when I had just CC it would be motorway only (and mainly only on continental motorways as well - where they seem to be able to control their own speeds and safety gaps unlike UK drivers)!
I don’t use mine often as I prefer to be in complete control with my feet. However, I can hold a steady 78mph regardless of up or downhill & find peoples erratic speed really very strange.
Or those that speed up as you are next to them, stay with you for a mile or so & then suddenly brake and slow down. I always wonder what is going on in their heads when piloting such a heavy piece of machinery at speed.
Watching mpg and slowing down uphill to save fuel?
Yes, thanks I understand that the system utilising the brakes downhill to keep the speed constant is not actually reducing the speed and so they will not come on then. I'm talking about when I manually reduce speed, say from 50 to 45mph, not by applying the brakes myself but by flicking the cc setting switch down to my new desired speed. Do the brake lights come on then?
The ACC on my Ioniq was a bit to keen on the old brake front. Say you had it set at 60 mph then overtook another slower vehicle at a peak speed of say 75. Once passed as you remove you foot from the throttle to ease slowly back to 60 the car would apply the brakes until 60 mph was achieved. All other cars I have owned have allowed a “cruise” back to the set speed.
I often wondered if the brake lights came on, either way I must have looked like a co..k, as I pass a vehicle then hit the brakes
Yip, they're brain dead !!
- - - Updated - - -
No. Definitely brain dead !!
There must be a certain rate of decelleration that manufacturers use as a standard for whether the brake lights are applied I think. If i set the energy recovery to low on our leccy car, they wont illuminate but higher settings definitely activate them when regeneration is slowing the car faster than ordinary foot-off-the-accelerator-pedal slowing.
If that makes sense?
Cruise control is only any good on a flattish road and can help save fuel especially on motorways.
It won't save fuel going uphill so you should disengage it and change down.
Not all cruise controls are the same. All BMWs seem to have "cruise control with brake function"...which states that "the BMW cruise control with automatic braking is a standard cruise control function that applies the brakes when the car's speed increases to maintain the set speed. This type of cruise control will not only keep your speed on flat roads but also while going up and down hill."
I'm pretty sure my fiesta doesn't do this and would accelerate down a hill under cruise control.
No idea whether the brake lights come on when the BMW brakes.
My wife had an ecosport which is built on a fiesta platform and this is definitely not the case.
Why is it only any good on a flattish road? If anything it’s most useful on hills as it automatically compensates and maintains a constant speed.
I use the ACC on my electric car all the time but especially in stop-start traffic. It seems to be more efficient than when I am doing the pedals too.
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I quite often see cars on the motorway doing 70 with brake lights seeming to go on and off repeatedly and I doubt it would be cruise control because its often on the flat where no brake would be required to maintain speed. I have to assume there are drivers out there that drive with their foot on the brake pedal or are in the habit of touching the brake unnecessarily.
If as OP suggested all drivers used the ‘2 second rule’ this would help, brake lights don’t come on if you just ease off the throttle when not using cruise so don’t really expect them to work when the car ‘backs off’ when the speed required is set, or if the car needs to slow.
Utter tosh.
If my car is still working with a good engine speed, shifting down will use more fuel.
My 1.3 A reg fiesta was able to manage all inclines in 5th on the motorway without issue at 70+.
The fact modern cars / drivers cannot means they are unable to drive or are just c words. F off saving fuel, or if you are, then get out of the right hand lane.
Really? I obviously need to learn about driving then.
Mjk2 maybe you should read this....
https://www.express.co.uk/life-style...cruise-control.
My 7.5 golf had it, it was incredible at making journeys less tiring.
The gap was an annoyance though as you keep falling further back. I found that sometimes the brake lights would come on but not always I assumed it depended how hard it was making the car slow down.
I had the use of a C-Class Merc coupe for a few weeks a couple of years back or so, no adaptive CC fitted though if you used the CC stalk to slow down by increments of 5mph it activated the brakes and, with that, the brake lights.
If a vehicle is slowed via physical brakes or regen in an EV then brake lights must automatically be activated.
How's that then? Surely it depends on the gradient? An auto running on CC should change up/down itself, a manual may require a change of gear though that's dependent on gradient/engine load/throttle position as well (and when the clutch pedal is used CC automatically disengages). It's inaccurate to state that the use of CC itself will lower fuel efficiency when going up hill.
I read the linked article, I had to chuckle about the anticipating the brow of a hill part. The CC on mine may take literally a second or two to back off the throttle though that's not even going to be pennies spent over me backing off manually sooner.
My reference was in changing down a gear to go uphill.
If your car doesn’t need a lower gear to go uphill, you are going to use more fuel in shifting down than keeping it in the original one.
This was the utter tosh part & see no reference to doing this in the article.
That's tosh, depends on how long/steep the hill is.
I am yet to find a motorway incline that is steep or long enough to require changing down a gear at 70+mph in a car. Even my Smart manages just fine.
ACC in Mazda turns brake lights when braking.
It also have some emergency stop system - when the car finds out that the accident is coming and it has to stop the car immediately - in that case also hazard lights are turned on.
My Discovery has this and I use it all the time.
Not sure if its an option on yours, but I have 3 distance options. I usually close the gap a bit to stop cars jumping in. I agree it's really annoying as your car has to slow right down to maintain the distance.
I've never driven with active-CC but this sounds a pain, especially when driving on the motorway shouldn't require the use of a brake pedal hardly at all. Waste of energy and brake pad.
The information on these threads in invaluable.
We've even got a fella who drives a Smart car telling us all about gear ratios
Not motorway admittedly, but when the m4 ends at Pont Abraham in Wales it becomes the a48 then the a40, long parts of both are dual carriageway where using cruise control at 60-70 is perfectly feasible. But there are a number of inclines though where the car starts struggling in 6th unless you either go faster or downchange to 5th.
In fact, on the Llanddowror bypass my 2012 1.2 fiesta would need to be in 4th with my foot pushing the pedal as far is it would go just to maintain 45-50mph by the top.
Do you have plain old fashioned CC or do you have 'Cruise Control with Brake'? If you are not sure, if you knock 10mph off with 2 clicks, does it stand the car on its nose or just coast? If it is fact plain CC, the brake lights won't come on under any circumstances unless you physically press the pedal. If you have the latter or the more sophisticated Adaptive CC then AFAIK, anytime the car applies the brakes (on a steep downhill slope for instance or when you request a large speed decrease) then the brake lights will come on. If the car thinks it can coast to the required speed without applying any braking (for instance for a single mph decrease or slight decline) then the lights don't come on. As Cardshark says above, it is also my observation that the lights come on for any level of actual braking, as opposed to controlled coasting by cutting throttle.
Last edited by Padders; 15th December 2022 at 12:11.
He also has a Cayman GTSThe information on these threads in invaluable.
We've even got a fella who drives a Smart car telling us all about gear ratios
Clown.
Headshot
Ooer, he's showing off now - show us your PCP agreement hahahahaha.He also has a Cayman GTS
Clown.
This total wet wipe should have his computer removed.
But you can always duck if someone say pulled you for selling a watch on another forum when you told others it was going back in the safe.
Tactical awareness.
Now, back on topic...
Went back in the deposit box yesterday. It will come out again in a week or two for the other forum
Did originally offer it to a WTB here but it went the way 99% of WTBs go. Would rather it went here with a donation to the fundraiser but can't have it all.
I assume it is with brake as I can click down 5mph at a time where it will cruise down, and I assume the lights dont come on then as it certainly isn'thard braking. But if I flick the switch with a lighter tap it will go down in 1mph increments. If I repeat this action very quickly the 1mph increments will add up to a 5mph decrease far quicker than selecting 5mph in one go. I wondered if the brake lights operate then, as it could certainly catch out an inattentive driver behind me if not.
Ah, ok...I've rarely driven in Wales (mostly east of UK) so wasn't sure.
In fairness Christian the actual m4 motorway in Wales fulfills your criteria of cruising at 70 and not needing to change down perfectly well. It's relatively flat apart from a few bits but any modern car should easily hold top gear at 70 all the way through.
I referred to the wild hinterlands beyond the m4 which was a little off topic I admit.
I don't think it has anything to do with whether you can click down in 1 or 5mph intervals really. If I read the thread right and you have a 2012 Fiesta then no I don't think Cruise with brake was an option, just the passive kind with no link to the brakes. You would know if the car was braking, it can be quite sharp. If you think about it, if you are driving without cruise and lift off for lights or a hill or whatever, there would be no brake lights so it makes sense that when the car manages your speed, the same applies. As alluded to earlier in this thread, electric cars with regenerative braking are a different kettle of fish as those can decelerate quite fiercely when you lift off and can be driven on a single pedal like a bumper car. There I imagine there must be a threshold beyond which the lights come on.
If your cruise works like this from 2013, then it isn't cruise with brake (and explicitly says so) but can drop 5mph at a time like you describe.
https://www.fordservicecontent.com/F...&buildtype=web
This isnt for the fiesta, but I have found the exact same in the 2013 Fiesta user manual pdf.
Last edited by Padders; 15th December 2022 at 13:38.
Yes, most cars will manage it, that’s not the point.
iPhone actually & never had a PCP.
Try trolling better, your pretty poor at it.
Come again?
I said changing down a gear after turning off CC uses more fuel - this is correct and cannot be disputed.
You said it was tosh, and depended on the steepness or length of hill (a somewhat irrelevant piece to the fuel economy statement)
You then jump back to say most cars will manage it, but it is not the point.
I am completely lost as to what point you are trying to make here. :D
Brush up on your spelling cash man, you're pretty poor at it
Mildly dyslexic, but take your wins, big man.Brush up on your spelling cash man, you're pretty poor at it
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