Isn't there a simple solution to the selfish merge problem? Maybe I'm naive, but... howabout instead of having lanes across which cars can merge like we do now, every transportation artery for self-driving vehicles could be a single lane (or a close approximation to a single lane). This is essentially getting rid of the "merge" part of the problem.

For example, if we had self-driving car tubes, then there would be no way to get out of the way of a car attempting to game the selfish merge. The car in front would sense that it is getting too close to the car in front of it and would have to slow down despite the high-probability of getting rear-ended by the selfish car.

At first, it would seem that this would require a whole new infrastructure for transportation. But you could achieve the "tube" effect by having barriers between all lanes with occasional splits or ramps to allow cars to get on and off the road. Further, this would be interesting in the transitional period between when no cars drive themselves and when all drive themselves: you could start with a dedicated lane for self-driving cars and then barrier-off successive lanes as the relative percentages of self-driving to driving cars increases.