gregbo (gregbo) wrote,

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traffic jam math

There's a thread on Slashdot discussing how some mathematicians have solved the traffic jam problem. This problem has actually been solved; I remember my queueing theory professor at UCLA discussing it. He gave an example of how people on the 405 followed each other too closely, and as a result, a small slowdown could result in a serious traffic jam a few cars back. He also said that truck drivers were instructed to leave a certain spacing between themselves (e.g. in a convoy) so as not to excessively contribute to traffic jams. After that, I modified my driving so that I don't follow too closely, and try to match my speed to the car ahead of me (even if it's a few car lengths ahead). If that car slows down, so do I, and anyone behind me is not quite as affected. I try to slow down enough so that I keep moving, just to keep everyone else behind me moving. (An unfortunate side effect of this is that sometimes cars will cut in front of me, even in near-standstill traffic.)

I thought that type of analysis was cool; it's what I went to grad school for. OTOH, I was dismayed that this type of insight didn't lend itself to some of the things that were giving me problems, such as graph theory (taken in the same quarter).

Along the lines of early exposure to science, etc. I remember when I was very young, asking my father why traffic jams occurred. I didn't understand why we couldn't drive at 55, even though that's what the given speed limit was, because people kept slowing down. I wondered why we couldn't just be given a "slot" that would allow us to move at the speed limit. (I didn't realize that I was describing is now a principle behind several types of data communications.) He didn't know; he had driven a truck in the Army, but perhaps the mathematics of traffic jams hadn't been solved yet. Anyway, this is the sort of thing I've been talking about – kids I know have parents, or friends of parents who know about science and can tell them things. For example, my choral director's son talks to one of our sopranos' husbands, holder of a Stanford PhD in materials engineering, about Stanford. He wants to study mechanical engineering there. The director knows all sorts of things about the curriculum, down to what the summer programs for kids thinking of studying engineering are like.
Tags: education

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