[Jason]

A little article on the Adaptive Cruise Control feature from Bosch, the makers of the technology in the E90.
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First midsize application

Bosch has launched its latest driving assistance system in the new BMW 3 Series – the first mid-sized vehicle from any manufacturer to feature this technology. Adaptive Cruise Control (ACC) detects vehicles in front of the car, calculates the traveling speed and maintains a speed-related safety distance between the vehicles through active brake and engine control. Once there is no vehicle within the scanning range, the system accelerates the car to the pre-selected speed.

Promoted as a safety feature rather than a ‘luxury’ item, in the USA the National Highway Traffic Safety Administration (NHTSA) has confirmed that ACC's benefits include "avoidance of crashes and a reduction in crash severity, crash-related fatalities and injuries". In addition, after evaluating an NHTSA test, the National Transportation Safety Board concluded that ACC could prevent as many as 12,000 collisions on US interstate highways each year alone.

A compact sensor control unit accommodating the radar sensor and the control unit represents the centerpiece of the ACC system. Four overlapping radar beams scan the area up to 200 meters in front of the vehicle. By emitting specifically modulated frequencies, combined with corresponding evaluation algorithms, the system is able to calculate the speed of the vehicles scanned and the distance to them. This process can simultaneously cover and monitor several vehicles located within the scanning range. By cross-checking cornering information delivered by the electronic stability program (ESP®) the ACC is able to select those vehicles that are relevant to the driver’s own car.

In addition to the ACC, Bosch also supplies BMW with engine management systems for gasoline engines, common-rail injection systems for diesel engines, the starter, the alternator, the airbag control unit, parts of the sensor system and the parking assistance for the new 3-Series. ZF Lenksysteme GmbH, a joint-venture company of Bosch and ZF Friedrichshafen AG, produces the steering column, the power steering system, the optional speed-controlled Servotronic power steering system and the optional active steering system.

[vivid]

I have Adaptive Cruise Control on my FX45 and all I can say is DON'T GET IT... It sounds really nice but... when you on a HWY and go round a curve ACC thinks its a car and slams the protection on... if the car in the next lane is close to your lane and you go round a mild curve ACC slams the protection on... The only time ACC is good is when you on a very STRAIGHT and EMPTY interstate...

this is an option I would never never get again. It is the most uncomfortable safety feature ever I have ever felt and I found if anything it is not a safety feature but a hazard because when it engages round a curve it is so aggressive in slowing you down that it is dangerous.

If you prone to falling asleep at the wheel, think about it but for all other just pass on this option...

Maybe the BMW system is better but I can't imagine it is, your eye can tell when a corner is not a car, a computer can't.

[Armen52]

I wonder, if you get the Active Cruise, is there any way to turn the "active" part of it off and just make it act like a normal cruise?

I should hope so.

[Athos]

Originally Posted by vivid

I have Adaptive Cruise Control on my FX45 and all I can say is DON'T GET IT... It sounds really nice but... when you on a HWY and go round a curve ACC thinks its a car and slams the protection on... if the car in the next lane is close to your lane and you go round a mild curve ACC slams the protection on... The only time ACC is good is when you on a very STRAIGHT and EMPTY interstate...

this is an option I would never never get again. It is the most uncomfortable safety feature ever I have ever felt and I found if anything it is not a safety feature but a hazard because when it engages round a curve it is so aggressive in slowing you down that it is dangerous.

If you prone to falling asleep at the wheel, think about it but for all other just pass on this option...

Maybe the BMW system is better but I can't imagine it is, your eye can tell when a corner is not a car, a computer can't.

Vivid,
Thanks for sharing your experience with adaptive CC. Very interesting. I think this is one of those technologies where I'd rather not spend extra money to be on the bleeding edge. I like the idea of adaptive CC but think it might need a few generations to work itself out. It'll be interesting to hear what other people who get it find out.

[vivid]

Originally Posted by Armen52

I wonder, if you get the Active Cruise, is there any way to turn the "active" part of it off and just make it act like a normal cruise?

I should hope so.

I can't turn it off in my FX, so I never use CC... Hopefully the BMW system will be better and you will have the choice to turn it off... time will tell

[RichReg]

Originally Posted by vivid

I have Adaptive Cruise Control on my FX45 and all I can say is DON'T GET IT... It sounds really nice but... when you on a HWY and go round a curve ACC thinks its a car and slams the protection on... if the car in the next lane is close to your lane and you go round a mild curve ACC slams the protection on... The only time ACC is good is when you on a very STRAIGHT and EMPTY interstate...

this is an option I would never never get again. It is the most uncomfortable safety feature ever I have ever felt and I found if anything it is not a safety feature but a hazard because when it engages round a curve it is so aggressive in slowing you down that it is dangerous.

If you prone to falling asleep at the wheel, think about it but for all other just pass on this option...

Maybe the BMW system is better but I can't imagine it is, your eye can tell when a corner is not a car, a computer can't.

If BMW was smart, they would find some way to integrate this feature with the active headlights, which swivel when you go around a turn. This way, it might somehow "understand" the concept of curves on a highway. Just a theory....

[glamprecht]

BMW ACC is much smarter. It uses the ABS sensors to determine if you are going around a curve. I don't find any problems with it incorrectly braking for cars in the wrong lane. It is incredibly smart and even adjust the reaction time for the car in front of you when you want to change lanes while using the indicator.

This is by far the most sophisticated piece of software in the car.