It is safe following distance if you can stop if the car in front of you stops. As in, you have to have time to react to the other car braking and then you have

It is safe following distance if you can stop if the car in front of you stops. As in, you have to have time to react to the other car braking and then you have time to slow down while that car is braking. Not if a standing obstacle comes from behind that car in no time. Especially if that obstacle is not visible through the car in front of you. After all, traffic rules clearly say "no stopping on highway" specifically for that. Even shoulder is only for emergency and you have to GTFO ASAP from there.