Traffic Shock Waves

Here is an experimental recreation of the traffic shock waves that uses one of the main idealized conditions (circular tracks, with cars attempting to travel at constant speed) that has been studied. My professor Gerald Whitham at Caltech was one of the pioneers in early, idealized models of such things.

(Tip of the cap to Wendell Misch.)

Overheard in ACM 210a

In ACM 210a today, Professor Tom Hou said, "You don't want to jump the shock."

This is my quote of the day, and it will require some unraveling to convey the full significance.

First of all, it immediately made me think of the phrase jump the shark, an appreciation of which is required to fully enjoy the quote above. If you don't know what that phrase means -- and most of you should because I've discussed it on my blog before -- you owe it to yourself to take a look at the wikipedia entry on the other side of the link I provided.

The topic of the class is numerical methods for partial differential equations, and in the class of systems we're studying right now shocks are very common. When designing numerical schemes to deal with systems that can have this stuff, they typically have to be lower-order near the shock because if you're going to use nearby points for interpolation, you don't want points on both sides of the shock. That is, you don't want to jump the shock. Thus, Hou's comment (which was completely intentional) makes absolutely perfect sense scientifically. Moreover, he is as far as I can tell completely unaware of the term "jumping the shark," so it seems that he doesn't realize just how funny that comment is.

If I ever discuss the numerics of such systems in a talk, I am so going to use the picture of the Fonz jumping the shark on one of my slides. Maybe only one or two people in the audience will get the joke because it admittedly requires a reference leap, but it is bloody awesome!