I find this stuff really interesting cause the rational choice for a single person (in the sense that every person maximizes his return) leads to non-optimal outcomes for the community.

Do you not drive when you travel? As someone born/raised in england and living in the US for a long time now, I find that while 4 way stops are much more “co-operative” than roundabouts … roundabouts are _much_ more efficient.

Merging two lanes into one sucks everywhere though :).

I would argue the zipper merge isn’t actually an equilibrium, which is to say that one player can unilaterally improve his outcome by not complying. From a sort of Rawlsian original position, it makes sense that we all agree we all want everyone to comply with the zipper, but the only consequence to not complying is the scorn of other drivers. While this could have implications in an iterated game (they might cut you off in future iterations of the game), real world driving situations usually don’t entail a likelihood of “playing” again with the same drivers.

Running a stop sign, on the other hand, usually entails an irrational level of risk.

True. To be honest, though, I don’t think I’ve ever actually seen game theory used to analyze those situations.

And those are actually still zero-sum situations, right? If you and I are big stacks with three players remaining at the final table, and we avoid playing big pots with each other, we are both gaining EV that is lost by the third player.

Cooperation at a four-way stop is truly positive-sum. No one wins in a car accident.

If you haven’t read the book Traffic yet you should, gets into this and the many other idiosyncrasies of how things play out on roads, very interesting/ terrifying.