They typically leave enough room to stop for their estimate of how long it would take the car in front of them to stop + the distance to that car. That initial estimate does NOT assume the car in front of them will stop instantaneously obviously.
While this usually will be fine, there are definitely issues when something stationary does pop up.
While caravan-ing to Yellowstone with 3 vehicles, all traveling in the center lane of the freeway, we encountered a small car with a passed out passenger in the middle lane. My bro-in-law swerved with some room to spare, immediately behind him I swerved with basically zero room to spare, and my father behind me (luckily for them in a Suburban, but bad for the man in the VW) had no chance- I was immediately looking in my back mirror knowing what I was going to see.
There is a decent likelihood that a machine could have swerved in time, but nearly zero that a typical human could/would have in our typical following patterns.
Humans route around inefficient practices. Just as human driving speeds are typically unaffected by posted traffic speeds, they will optimize for their typical experience over written codes for how they drive.
While this usually will be fine, there are definitely issues when something stationary does pop up.
While caravan-ing to Yellowstone with 3 vehicles, all traveling in the center lane of the freeway, we encountered a small car with a passed out passenger in the middle lane. My bro-in-law swerved with some room to spare, immediately behind him I swerved with basically zero room to spare, and my father behind me (luckily for them in a Suburban, but bad for the man in the VW) had no chance- I was immediately looking in my back mirror knowing what I was going to see.
There is a decent likelihood that a machine could have swerved in time, but nearly zero that a typical human could/would have in our typical following patterns.
Humans route around inefficient practices. Just as human driving speeds are typically unaffected by posted traffic speeds, they will optimize for their typical experience over written codes for how they drive.