I have the old model of lane assist which doesn't detect speed limits, bends etc., but I think you can switch off these more recent extra facilities, which is possibly a good thing (hopefully staying reset when you switch off the engine). I actually really like my older style ACC and wouldn't buy another car without it, but I do let it influence my driving style to a certain extent, to accommodate how it works. It can be annoying if you don't adapt, as it is a bit slow to unlock from a slower car in front, when pulling out too late on a motorway. It then puts on the brakes just at the worst time, as you note. Solution pull out in plenty of time, giving the system time to disengage. Thus it encourages anticipation, never a bad thing. That early pulling out can annoy motorists in the fast lane exceeding the speed limit, who might have been able to nip past otherwise, but sod those law breakers, why should I worry about them. As a last resort, if you do leave it too late when pulling out, put your foot on the throttle until the system sorts itself out. There's a little car symbol that comes on the screen in front of you, when ACC detects a car in front and conversely you know when it has disengaged when that symbol goes away. Another quirk - it is also slow to pick up a new car appearing in front of you, i.e. someone who cuts you up, so you do have to stay alert - again maybe no bad thing. You can adjust the sensitivity and some people like the fast setting - allows you to get closer to car in front, without the system recognising it (but then does brake faster) and accelerates faster once it unlocks from that car when overtaking. They say overall in practice, it does lead to less unnecessary braking. I did use it for a while and I recall I generally concurred, but it gets set to default at dealer servicing and these days I don't get round to resetting, maybe I should try that again. There are other useful things to note about how it operates, but I've already gone on too long. I find ACC makes long motorway journeys more relaxing and less tiring, yet keeps me more attentive of road conditions. It took a while for me to adjust, not using it at first on the busy M25, but no problem even there, now, I just go with the flow. It has malfunctioned twice in really heavy rain, simply turning itself off with some warnings, so it failed safe, but otherwise I find it totally dependable. However, you'll find quite a few here who much prefer simple cruise control, but I just don't agree, ACC is safer. Never tried lane assist (would like to), but more people criticize that than they do ACC.