Two seconds distance. On the highway, between my car and the car in front of me. In the fairly busy traffic, with at each 600 meter matrix signs giving an early warning for sudden jams I was not used to do that. But eventually one does learn from bad experiences. Not that I am afraid that I will react too late. My response is still fast and I never fall asleep.

No, the problem is the cars behind me. Their drivers react slower than me. So these cars will bump into my car when I suddenly brake. And a crash from behind is a tough one, at least for the one in front. It takes about three weeks before your neck is recovered. At most one such a crash in a lifetime, but better none at all.