I really like the automatic cruise control on my fairly new Honda Jazz. I've found that it has a net positive effect on my attention to the road, because I become less fatigued from the small, brief slowdowns that I might encounter on a motorway. There was actually an instance where I narrowly avoided a crash while using this system because of how quickly I acted when a potentially dangerous situation developed into an active crash; I felt like I was more alert than I would've otherwise been after a day of driving

However, I do not like the lane-keeping system, especially combined with the automatic cruise control. I remember testing it when I was on a clear but fairly curved section of the motorway, with my hands completely off the wheel (but hovering over the wheel, ready to take control again if necessary). I was horrified by how effectively it took me round the bend — effectively enough to be dangerous. There is a warning beep if you spend too long without your hands on the wheel at all for a while, but this was just something I did while testing it. I've not used it since, because I was confident that, unlike the automatic cruise control used on its own, this would diminish my attention and leave me unable to properly respond to an exceptional circumstances.