Traffic Jam Game Theory

You know a traffic jam is bad when you have enough time to contemplate how an economics principal you learned in college could be applied. 

From what I remember of Econ 1001, game theory is all about predicting how people will act to maximize their own outcomes in a given situation.  It analyzes how those decisions impact (and are in turn impacted by) the decisions or potential decisions of others.  Some classic game theory examples include the prisoners’ dilemma and the tragedy of the commons.  Well, I would like to add traffic in China to the official list of applied game theory fields.

The Prisoners Dillemma is an example of game theory at work.

The Prisoners Dillemma is an example of game theory at work.

You see, most of the time enough Chinese drivers follow the laws, stop at red lights, and otherwise drive such that traffic can flow relatively freely.  They recognize that doing so gets everyone from A to B faster.  Nonetheless, a small number of drivers always continue to run lights, clog intersections even after lights have changed, and weave use oncoming traffic lanes for a period.  As long as the majority of drivers are behaving, these drivers can take advantage of the system and get to their destination a bit faster.

From time to time though, enough people start trying to break the rules at the same time, and things fall apart quickly.  In rush hour, when one car tries to turn and there is no room, it can block traffic.  This in turn encourages other cars to screw the rules and go around any way possible.  This in turn leads to even weirder stoppages in traffic the next light sequence, which encourages even weirder circumvention maneuvers.  The vicious cycle continues until no one is going anywhere at all, literally. 

Ironically traffic directors (at right) often just watch traffic jams occur.

Ironically traffic directors (at right) often just watch traffic jams occur.

Yesterday, my bus was trapped in the intersection right outside our house for 10 minutes.  For about five of those minutes, literally no cars were able to move.  It felt like one of those “slide the tiles around one at a time until you can get them all in the right order” games.

The intersection felt a lot like a sliding tile puzzle.  Only one car could move at a time.

The intersection felt a lot like a sliding tile puzzle. Only one car could move at a time.

See what I mean?

See what I mean?

A little to the left.

A little to the left. Even the biker was stuck.

A little more to the left.

A little more to the left.

Considering that this scene was playing out on the other side of the bus too, you can see why it took us 10 minutes to get through the intersection.  The best part was that no one at all thought it was out of the ordinary.  People kept their cool and just waited and waited…inching ahead whenever they got a chance.  I laughed out loud and realized how much I’ve grown accustomed to this type of absurd situation in the last seven months.

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2 comments

  1. Jeff,
    I like your game theory and your insight into developing tolerance. My Dad had a different theory that might apply to a microcosm within each traffic jam. When he experienced Beijing traffic he commented that it was typical of everything in China in that you constantly were negotiating. That it was training for fearless bargaining. On the road you negotiate for space, in every encounter you negotiate price or space. It distracted me from giving into fear of my life and my kids’ lives each time we attempted to walk across a street.
    Martha

    1. Martha, I like that interpretation of the traffic as well. Negotiation is a part of everything here, up until the last minute. Really though, for the most part I enjoy commuting in China. Even though it has its downsides, I LOVE not having a car. I enjoy not having to pay for it especially. I also appreciate the exercise. Hope all is well!

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