I think this behavior is taught now, since a car that never uses its brakes but reduces its speed will give a false impression to the car behind that it's travelling at the same speed as it was a second ago.

This mental picture always brings to mind "Mambo No. 8" by Perez Prado (I remembered the song name, but had to look up the artist) from the beginning of "Office Space" when the traffic is START/STOP, and as he pulls into the faster lane, IT stops, and the former lane moves along, only to switch back and have the same thing happen. Hysterical movie.

I think the most impressive move in regards to slow-moving traffic is the "Never-Stop-Stop", where the driver will move along with traffic, and when the cars ahead come to a full stop, they apply the brake *ever* so gently, and slowly drop from 1mph, to 1/2 mph, to 1/3 mph, and just at the event horizon where you think said driver will have to swallow their pride and stop completely, the cars ahead move along, and they can apply gas again.

Life/dignity restored. Ego boosted. Cosmos synchronized in unison.

What a feat!