Self-driving cars can use game theory to generate a better vehicle code and cooperative road

Traffic jams with selfish drivers could become a thing of the past.

The rise of self-driving cars offers the potential for an entirely new way of regulating vehicles. First, because you can get all the "drivers" of self-driving cars in a room, rules of the road can be quickly negotiated and settled directly, and adhered to robotically, rather than writing complex sets of regulations.

There is a bigger potential though for a new type of self-regulation which would permit much more than can be done with legal regulation. That is to consider all the robocars -- and eventually the human drivers, as players in a version of the famous "Prisoner's Dilemma" game using the "tit for tat" approach which strongly encourages not just compliance with rules, but active cooperation -- you yield to me and others will yield to you so everybody wins.

I discuss this is a new article at Self-Driving Cars Can Also Self-Design A Whole New Traffic Code


Good article - one minor comment, the Pittsburgh left is actually an optimization that benefits all drivers. There are many intersections with no room for left turn lanes, so a driver making an immediate left often prevents people behind him from having to wait for a partial or whole cycle.

The question is, while the Pittsburgh left does let that first in line car get their left turn, it happens by delaying the whole intersection. Clearly you can come up with better algorithms for intersections if your goal is maximum for everybody and it might well have people waiting for left turners (which of course is what a left arrow light usually does, though some put the left arrow at the end rather than the start, or even vary it.)

I am guessing in Pittsburgh, if you are waiting to go straight, you hold back on the green in case somebody is going to do that PB Left.

Yes, the Pittsburgh left lets that first car in line get their left turn, but more importantly it lets all the cars behind it (that aren't turning left) not have to wait.

That's the while purpose of it, and if you don't do it, the people in the cars waiting behind you will probably honk at you for not doing it (if you're in a place where it's practiced, which is by no means limited to Pittsburgh; any place in the USA with lots of two lane roads with unprotected left turns probably practices it). I was surprised the first time I heard you mention the practice in a derogatory manner, as I had thought all my life that it was the standard practice everywhere when making a left from a two lane road.

The Pittsburgh Left is both selfish and cooperative. The idea that it can't be both is misguided.

This was very interesting to read, thank you for sharing!

You mention the game theory concept of "tit for tat", but on a population level, where individual cars will yield and facilitate other cars, expecting a similar behavior in return. It turns out that this kind of strategic interaction is significantly more complex than the textbook-version of the repeated prisoner dilemma. We are looking into this kind of solution at ETH Zurich. We just scratched the surface, but the results are promising: as you conjectured, it seems that this system would yield an efficient use of the road, and no unpractical (unfair, also?) monetary transactions are needed. A "karma" system, instead.

"Today Me, Tomorrow Thee: Efficient Resource Allocation in Competitive Settings using Karma Games"
Andrea Censi, Saverio Bolognani, Julian G. Zilly, Shima Sadat Mousavi, Emilio Frazzoli
ETH Zurich

I will be looking into this for my PhD and I am looking forward to reading more of your thoughts.

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