Need a PhD Topic? How about cops in traffic

An interesting question, but I must ask — why is the answer important?

I could see this being possibly useful in traffic "wave" disruption. I've read on the traffic wave theory before and there has been some ideas that if the wave could be disrupted long enough to clear out that it would dissolve and traffic would start to flow again at its normal pace. I suppose that disruption could be done by police cars allowing buffers to build thus disrupting the wave.

Can you tell I find this field fascinating? Full disclosure I have a degree in Operations Research.

Déjà vu: http://news.ycombinator.com/item?id=1626403

Sans the copper, they do this over here in the UK by using variable speed limits, hard shoulder 'opening' and the real threat of speed cameras.

Seems to work in my albeit anecdotal and very occasional experience of driving near Birmingham in rush hour. Would be interested to hear the perspective on UK HNers who were aorund before/after they implemented this.

And they're using it more and more:

http://www.bbc.co.uk/news/uk-england-13426799

As it happens, I studied traffic flow back when I was an undergrad in the context of "agent based modeling".

Agent-based models are basically computer simulations where you throw N 'agents' into an environment with pre-defined rules and then watch how they interact with each other. This setup lends itself perfectly to vehicle-flow; each agent is a car, each car has a model for when it accelerates, when it slows down, when it turns, and so forth. Create enough of them, and you can start to simulate traffic jams and other interesting traffic phenomena.

Now, I have not studied this problem in particular. My research was on the effect of excessive lane-changing on overall traffic throughput (Spoiler: lane-changing tends to cause traffic to slow down behind the lane-changer, which means that system-wide lane-changing leads to traffic jams, but changing lanes is a strictly superior strategy for individual drivers in most situations. The classic collective-action problem. Economics!)

However, it seems to me that it would be relatively simple to extend a traditional AB traffic model to include special vehicles that impose constraints on nearby cars.

If any of you are interested, there is an excellent java library developed at UChicago called Repast [http://repast.sourceforge.net/index.html] which contains a framework for building agent-based models.

You may also be interested in my favorite book on the subject, "Micromotives and Macrobehavior" [http://www.amazon.com/Micromotives-Macrobehavior-Lectures-Pu...] which is more rigorous than its Amazon description would have you believe.