You're assuming you've always got the choice to keep the distance. Sometimes you don't. If you get in a tight alley where you have to pass a truck, you can't do

You're assuming you've always got the choice to keep the distance. Sometimes you don't. If you get in a tight alley where you have to pass a truck, you can't do it differently. Whatever safety system you use, one day it either won't help in the situation, or you'll forget about it. Overconfidence in your control may give you a really bad lesson in humility. You can also see the recent video of a Tesla avoiding a person falling onto the street and crashing into another car. There's no reason to keep the speed lower in that area, no extra space to be away from the sidewalk and no time to react to the change.