Here's the trick when driving on highways to clear up traffic jams: try to move at a flat, constant speed, such that by the time you would reach the stopped car in front of you it has already started moving again.

To the people behind you, traffic appears to be moving at a constant speed. The wave stops propagating backward and the jam clears up.

I love doing this, it feels nice to think that I am playing a small part in helping to reduce the propagating wave for people behind me :)

Until the inevitable jerk takes the 1-car length space in front me as an invite to try to find a faster lane, making me hit the brakes and strengthening the traffic wave instead of weakening it :(