I am just excited because the more EVs mean fewer idiots in hot rods running without mufflers.
But yes, they can be turned off.
With Tesla it's all-or-nothing, and when it inevitably drives poorly, I can only turn it off. It physically resists me turning the steering wheel while it's driving, and overcoming the resistance results in an unpleasant and potentially dangerous jerk.
OTOH in IONIQ I can control lane assist and adaptive cruise control separately. The lane assist is additive to normal steering. It doesn't take over, only makes the car seem to naturally roll along the road.
Over say 50km part of highway, maybe 2000 cars need to overtake such almost stationary object (to regular traffic which generally moves exactly at the speed limit). Fine if you have 3+ lanes, but most highways in Europe have 2 only. Then you have all the trucks, buses and rest of traffic trying to overtake via that 1 free lane, which in heavier (but still cca smooth) traffic will create a massive moving traffic jam immediately.
If I didn't see this every other day (and for some reasons its 90% tesla drivers where I live and rest is caravans) I wouldn't believe it to be so common, but it is. Summer now makes it even worse with all holiday drivers.
Was very concerned until I realized you were talking about kilometers and not miles.
Otherwise, I'd hope the average driver would firce themselves to drive slower than 120mph out of some sense of fear, or at least a sense of self-preservation.
80km/h is the usual maximum allowed speed for trucks, at least in Germany, so no idea how a car driving 90km/h is such a big problem. That's not a "stationary object" at all, far from it. You are even allowed to drive vehicles with a minimum speed of 60km/h on the Autobahn.
If a car driving 90km/h is the cause for a traffic jam there are definitely other factors at play. Not just in zones with a limit of 120km/h but everywhere even without limits.
so just like any truck.
if you think it's a problem, you're the problem. sorry.