Automatic lane-keeping assist is generally turned on at all times with modern cars.

It’s not in either 2023 model year vehicle I own, but I have seen it on full time in another. But I have never seen it active below speeds of about 35mph (i.e. most city driving)

Interesting; when did this happen? From my experience, ~2017-era cars had it only as part of cruise control.

Keeping it on at all times sounds like a terrible idea for cars used in the US, because it's a developing nation with extremely poor road quality. In developed nations, it's probably OK because you can count on the road markings being good almost everywhere, but not in the US.

I think it only turns on above certain speed and yes, it can get easily confused by various road imperfections.

But yeah, you need to make sure there is a physical button on the steering wheel or somehere on the dashboard to easily enable/disable it. Otherwise it can be annoying.

My 2017 Pacifica (built in 2016) has lane keeping on by default without cruise control. I'm pretty happy with its light touch, so I wouldn't expect it to really move me out of the de facto lane into the lane it senses, but it could try. I'll manually turn it off for snowy roads, but otherwise let it do it's job of supervising in case the human screws up. Otoh, other vehicles may have a stronger correction, or my least favorite where they just beep a lot.

It is on by default in my 2020 Mazda3. After giving it (and all the other safety features) a chance for several months it's muscle memory to flip off all safety features during city driving. Thankfully there's a single button that does that, just left of the steering wheel.