Comment by scott_w

The few Tesla post-mortems I’ve read early on stated that FSD turned off before impact and used this as a defence to their system. If they shared that this happened 1 second before impact (so far too late for a human to respond), I’d have sympathy. I have never read a Tesla statement that contained this information.

For normal incidents, 2 seconds is taken as a response time to be added for corrective action to take effect (avoidance, braking). I’d expand this for FSD because it implies a lower level of engagement, so you need more time to reengage with the car.