There’s a minimum safe following distance that’s necessary to avoid accidents.
If they’re too close, I’m in danger of getting rear-ended.
The safe following distance depends on the speed we’re going.
I can’t control how close the car behind me is driving.
But I can control my speed.
So I blip the brake just enough for the brake lights to come on and get their attention, then coast without gas and slow down until my speed matches their distance.

(They’ll pass me long before that)