Until we eliminate the human driver from the equation there will be no solution to this problem.
The resulting standing wave continues until the traffic coming up onto the wave becomes so light that the wave cannot continue to propagate. In essence, it requires a traffic vacuum to eliminate the standing wave. This is why so many traffic problems seem to have no discernible cause.
The cure to the phantom wave is to eliminate the human from the driving equation. Robots will simply have less of the human error which causes these problems, and so traffic will flow much more smoothly. Even during the initial phase of the self drive car ramp up, the addition of these cars should have a significant and salutary effect on traffic.
We can't wait for the self drive car!