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BMW Active Cruise Control with Stop & Go function.

9K views 14 replies 12 participants last post by  tntp 
#1 ·
Re-posting this from the BMW site. Unfortunately this feature is not available on a X3. The X5 and 3 series have this as an option. Looks like a great feature to have on long trips or on heavy traffic.


BMW Active Cruise Control with Stop & Go function.

Relaxed driving even in heavy traffic: Active Cruise Control with Stop & Go function ensures that your BMW remains a predefined distance away from the car ahead, reducing the speed to zero if necessary. When the traffic begins to move again, the system accelerates your BMW - up to your preferred cruising speed if possible.

Active Cruise Control (ACC) with Stop & Go function is primarily intended to serve as a driver assistant on freeways and highways. Three radar sensors with a range of up to 150 metres permanently monitor the road ahead. As you approach a slower vehicle in your lane, the system directs the engine control unit to reduce power output and if necessary apply the brakes to ensure you remain a predefined distance away. If the vehicle ahead stops, ACC with Stop & Go will bring your BMW to a complete standstill too.

When the vehicle ahead moves off again or changes lanes, ACC with Stop & Go increases engine power; if possible, your BMW accelerates to your preferred cruising speed. If the total standstill is longer than three seconds, ACC with Stop & Go requires you to briefly apply the accelerator or press the ACC button to bring your BMW into motion again. If the standstill is briefer than three seconds, acceleration is automatic. Up to four different cruising speeds can be predefined and activated by the press of a button. Minimum cruising speed is 30 km/h; maximum is 180 km/h.

The distance to the vehicle ahead is measured in seconds rather than metres. This ensures that you have adequate reaction time in relation to the speed you are travelling at. ACC with Stop & Go makes driving both more relaxing and safer.

It adjusts your speed if needed on bends, using data from DSC and the navigation system to calculate a safe speed. On multi-lane roads, the system is able to differentiate between vehicles in your lane and in neighbouring lanes. ACC with Stop & Go function can be deactivated at any time by applying the accelerator or brake, giving you complete control over your speed.

It is important to remember that Active Cruise Control with Stop & Go function is not an autopilot. If the vehicle ahead brakes heavily and suddenly, or if the system recognises a critical situation, it alerts the driver with acoustic and optical warnings. Nonetheless, ACC with Stop & Go makes driving in heavy traffic or moving through congestion significantly less tiring.
 
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#3 ·
...but someone will certainly be asking, "Where can I get the parts to add this option"? :)
 
#6 ·
Active Cruise Control on my 550i is awesome. It works quite well.
 
#7 ·
I bought our 2015 X5 with Active Cruise Control with Stop & Go. My MB S600 had a similar feature and we won’t buy a vehicle without it now.

Things I love:

* Heavy traffic doesn’t take so much concentration. You just keep the car in the lane. Two hours in heavy traffic is still annoying but not so tiring.
* The radar is much better at anticipating changes in the car in front than I am. This means the car reacts instantly to the car in front slowing instead of my 0.5 second delayed reaction time. The result is less need for aggressive braking.
* The aggressiveness of the speed adjustments is tunable with the driving mode. In sport mode the ACC will accelerate and brake harder than in Eco mode. Comfort mode is compromise between the other two modes.
* I never feel like I am not driving the car. The car is adjusting my speed but I can accelerate and brake any time I want.
* In Eco mode the car uses the alternator to slow down before using the braking system. I get better mileage and less brake wear.
* My wife is much more relaxed because she know the computer is always paying attention. I am an attentive driver but wife is generally nervous when anyone is driving. With ACC she seems much more relaxed with both the computer and me paying attention. And when the car slows abruptly she knows it is caused by the car in front and not me.
* Folowing distance setting ranges seems about right. On the shortest setting the car follows a bit less than 2 seconds. This seems about right to avoid inviting people to jump into your lane. The farthest distance is a bit over 3 seconds, which feels relaxed and smooth for passengers.

Things that could improve:

* Our ACC version does not properly recognize someone jumping into your lane. So the car does not slow down until the first rear corner of the intruding car is in the center of your lane. At higher speeds this is fine. But under 20 MPH our car gets too close to the intruding car and I have to brake.
* BMW seems to view these advanced safety/convenience features as a high-end luxury option. Either that or the reaction from the “I always want to be in control of my car” crowd had convinced them they don’t need features that Accords come standard with now. My wife and I wanted a m235i three years ago but couldn’t get ACC. I told her to wait. Oldly you can now get the ACC on a 230i if it is fairly stripped otherwise. My wife is not a fan of the larger 4 series. She fell in love with the tight reflexes of the m235i and the m240i. I had her convinced to get an M4 and then found out you can’t get an M4 with ACC. I think we’ll end up with an Audi S5 as a result.

Hope this is useful to anyone deciding on the feature.
 
#8 ·
* In Eco mode the car uses the alternator to slow down before using the braking system.
LOL. Momentum is conserved. The alternator weighs maybe ten pounds, the X5 weighs nearly 6000 pounds. What change in angular momentum of the ten pound alternator equals any change in linear momentum of the X5?

A typical X5 alternator puts out 220 Amps max times nominal 12 VDC < 5 horsepower brake equivalent.
 
#11 ·
I don't want any more unnecessary parts on the car. SIC Didn't even want the moon roof. Those extra parts will die and you will pay an arm and leg to fix, if you have mechanical ability. The times I am driving on the road, I can look up and see merging cars, slow traffic, an accident ahead, and many other visual ques to take my foot off the gas and apply to the brake. Are people getting that lazy?
 
#13 ·
I rented a car with adaptive cruise control on a business trip last month - I found it annoying.

I took the radar detector out of my truck because it was going off constantly from the signals coming from vehicles around me. There are no doubt radar detectors on the market that can filter this out, but for me it wasn't worth the expense to upgrade.
 
#14 ·
I have this feature on 2016 X3 35i. I do use it quite a bit, but it's best in light traffic and two lane highways. It's very accurate at matching speed, but it leaves quite a gap at highway speeds even if adjusted to it's 'closest' setting. It will slow the car down to maintain that gap if somebody new pulls in front of you. So you end up driving like a fearful slow poke when on the freeway. Such behavior is not so evident on two lane highways, where passing is rare.

The other thing I'll say is it's not as smooth a driver as I am. It's reactive; I'm predictive. It's a sequential processor and has limited memory; I'm a massively parallel processor and I have as many neurons as there are stars in the galaxy. Computers have been around 50 years or so, I'm the product of 500 million years of evolution. The good thing about the active cruise control is that it never gets distracted. So I'll put up with it's childish mental agility for it's Zen like attentiveness.

Other things about it:

If you come to a complete stop and have either Auto Hold on or engine start-stop enabled, to get going again you have to tap the accelerator. Otherwise it will sit there like an old stable horse until you wake it up.

You can't turn off the feature of matching speed to the car ahead. I would like the option to have it revert to prior generation behavior.

BTW, and rant warning: It's to me more evidence of why driverless cars will never work, unless 100% of them are in some big brother network. If you want to know what that is like, see the opening scenes of the Bruce Willis version of Twelve Monkeys, where he's caught in a traffic jam for several years! Another example is the feature my rig has to read speed limit signs. I'd say it's about 75% accurate, meaning 25% of the time it is dead wrong, dead being the operative word here. Imagine your driverless car turing off a 60mph highway to a farm road with no speed limit sign. How fast shall it go? What wisdom would it possess to infer a safe speed? I did this yesterday and it just stayed at 60 mph. (Fortunately, it's display only, and is not coupled to the cruise control.) I'm 70 years old and I may yet live long enough to see the coming driverless carnage. rant off, but it was fun; I have more examples, but this is enough
 
#15 ·
I have this feature on 2016 X3 35i. I do use it quite a bit, but it's best in light traffic and two lane highways. It's very accurate at matching speed, but it leaves quite a gap at highway speeds even if adjusted to it's 'closest' setting. It will slow the car down to maintain that gap if somebody new pulls in front of you. So you end up driving like a fearful slow poke when on the freeway. Such behavior is not so evident on two lane highways, where passing is rare.

The other thing I'll say is it's not as smooth a driver as I am. It's reactive; I'm predictive. It's a sequential processor and has limited memory; I'm a massively parallel processor and I have as many neurons as there are stars in the galaxy. Computers have been around 50 years or so, I'm the product of 500 million years of evolution. The good thing about the active cruise control is that it never gets distracted. So I'll put up with it's childish mental agility for it's Zen like attentiveness.

Other things about it:

If you come to a complete stop and have either Auto Hold on or engine start-stop enabled, to get going again you have to tap the accelerator. Otherwise it will sit there like an old stable horse until you wake it up.

You can't turn off the feature of matching speed to the car ahead. I would like the option to have it revert to prior generation behavior.

BTW, and rant warning: It's to me more evidence of why driverless cars will never work, unless 100% of them are in some big brother network. If you want to know what that is like, see the opening scenes of the Bruce Willis version of Twelve Monkeys, where he's caught in a traffic jam for several years! Another example is the feature my rig has to read speed limit signs. I'd say it's about 75% accurate, meaning 25% of the time it is dead wrong, dead being the operative word here. Imagine your driverless car turing off a 60mph highway to a farm road with no speed limit sign. How fast shall it go? What wisdom would it possess to infer a safe speed? I did this yesterday and it just stayed at 60 mph. (Fortunately, it's display only, and is not coupled to the cruise control.) I'm 70 years old and I may yet live long enough to see the coming driverless carnage. rant off, but it was fun; I have more examples, but this is enough
It's just a matter of time as computers are getting smarter and smarter and senior people's driving skills will degrade with age. I probably feel a bit safer if all seniors driving cars with ACC regardless they actively use the ACC or not. There is an embedded (passive) auto brake function at higher speed with the ACC package just in case !
 
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