5 seconds is not nearly enough time. If you need to drive 3 seconds behind a vehicle going the same speed as you to have safe reaction time & stopping distance,

5 seconds is not nearly enough time. If you need to drive 3 seconds behind a vehicle going the same speed as you to have safe reaction time & stopping distance, then you certainly can't (a) move your attention back to the road you weren't looking at because "autopilot" "self-driving" and (b) react to a stationary object and (c) come to a stop, all in 5.