So, Your Humble Blogger has a bit of a new driving route these days, so I’m spending more time on one of those numbered state road that is one-lane, 45 mph, widening to two lanes for a traffic light every half-mile or so. You know: the merge sign is visible from the other side of the intersection, if you’re stopped at the light.
OK, I’m not sure how to describe this. Let’s call the first car in the left lane A, and the one behind it B, and the first car in the right lane C and the one behind it D. So A is next to C at the light, and behind them, B and D. Got it?
Now, the amazing part is this: usually, it works just fine. The light turns green, the cars start up, and in a half-block they are in one lane, A followed by C followed by B followed by D, all going 45 or more likely 55 miles an hour. That’s pretty fast maneuvering, and we manage it because it’s a pattern we all recognize, and we do it all the time, and most of the time we just ease into it without thinking. Think about how much work you have to be doing to drive a car anyway, how much pattern-recognition, extrapolation, co-ordination, all that stuff, and here’s a pattern half of high school graduates screw up on foot (at their graduation) and we do it all the time at high speed in two-ton death traps without thinking about it. Pretty cool, hunh?
Particularly because it isn’t always exactly the same. We’re prepared for car C to go slow, or for car C to go fast, or for car B to act like a dick, or a few things like that. Some of the time instead of A-C-B-D it goes A-B-C-D or C-A-D-B, or C-A-B-D, or A-C-D-B, and nobody gets hurt.
What set me thinking about it, though, was that yesterday I was car C, and we ended up D-A-B-C. And still nobody got hurt. And that’s fancy drivin’, Tex.
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-Vardibidian.
I’m always interested to see how driving patterns creep into other areas of life where people are moving around. On campus at Caltech, there are pedestrians, maintenance people in carts, cyclists, skaters, and skateboarders, in approximately that order of frequency, and they generally manage to flow around and across and past each other without anyone getting decked, with patterns not unlike driving patterns, but adapted for the different sizes and shapes. There are also some local rules, like the carts will generally yield to anyone. It also creates some unexpected results; for example, bikes and pedestrians interact in one of two ways: The pedestrians will either ignore everyone else (which is fine, it means everyone else can navigate around them) or try to anticipate what everyone else is donig (which is much worse, because then they start jumping in front of you just as you turn to avoid them). Bikes and carts, on the other hand, get along great, regardless of who takes and gives the right of way, perhaps because they’re more aware of the fact that they’re in traffic. The pedestrians who freak out seem to be always discovering the fact that they’re in traffic — a constant stream of “oh crap! I’m in the street! whew! oh crap!” as vehicles go by.
Anyway, we digress. :^) My main point is that this dance isn’t limited to cars, and it really is kind of amazing that it works as well as it does.
When I was spending more time in traffic than I currently do, I often had occasion to muse about a Traffic Simulation Modeling Language, a way of representing silly traffic situations on a computer; a TSML viewer could read the representation and display an image or an animation showing how the situation played out.
Sadly, I never got any further than thinking it would be a good idea.