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I just learned from Volvo that ACC and PA cannot function simultaneously, i.e., when one is being used, the other cannot be used. That is interesting and, as I think back, it may be true, since they essentially work in different worlds. PA is primarily used at highway speeds to keep you on track, whereas ACC shines at lower speeds to keep you from colliding with the vehicle in front of you and to accelerate automatically when traffic moves. I have never noticed PA trying to steer me as I approached the vehicle in front of me, but I may test it...safely, of course.
 

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I don’t believe Pilot Assist will steer you around a vehicle. I use PA on city/suburbs driving all the time if it’s available. PA uses the same hardware as ACC.
 

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PA is to keep you within the lane, not to steer you away.

and of course, PA always also enable ACC.

The steering away you mentioned is another emergency safety feature when road condition allows and full braking is not enough to avoid collision. Nobody tested it on purpose though.
 

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PA is just ACC + steering assist. If PA is active, so is ACC. (You’ve noticed it changes speed, right? That’s the ACC.)
 

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There's also the option on the left panel of the Sensus menu for collision avoidance, where it may swerve to the left of an obstructing vehicle.

As far as I can tell, all the accelerator and brake behavior of ACC is retained when in PA mode. The only difference is the steering wheel is active in PA. And the steering wheel action in PA is different from the LKA (lane keep assist) feature that only provides slight steering wheel nudge into the lane.
 

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Yes in playing around with PA and LKA I’ve found that sometime PA loses the lane market starts to drift off and LKA gives me a warning. Weird that one can see it and the other not.


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Yes in playing around with PA and LKA I’ve found that sometime PA loses the lane market starts to drift off and LKA gives me a warning. Weird that one can see it and the other not.
Assuming both PA and LKA use the same processed set of information, it makes sense that the PA's higher level intervention is set up to require more certainty around its estimate of the road ahead, while the LKA, being a lower level intervention (of simply mild nudge when vehicle location estimate is near an edge) can operate with slightly lower certainty. When I go through a merging lane, sometimes LKA seem to try to nudge the steering wheel in the opposite direction, but it doesn't seem to countermand my applied torque to the steering wheel completely. That it is quite a low effort feedback probably also figures into its willingness to operate at lower levels of lane position certainty.
 
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