The Butterfly Effect on the Expressway
My driving theory (see Part 1), if universally applied, could in my opinion solve many of the congestion problems we face in the city and on the expressways. The reasoning is couched in a little basic chaos theory.
Chaos theory is that relatively new science that states that any system, no matter how simple, has a certain balance of order and chaos. As a system increases in complexity, a very tiny event can cause very large changes in the system. The textbook example is of the butterfly in China that flutters its wings and causes a snowstorm in New York; since weather patterns are extremely complex, the tiny effect of the butterfly’s wings could theoretically result in a cascade of effects, each more powerful than its predecessor, until finally the east coast is socked in by a blizzard.
Highway driving is much the same. Each car is an individual element of a complex system. They all follow some basic rules, such as stay out of the ditch, try not to stop, etc., but also each driver has a different style, choice of speed, level of aggressiveness, etc., that makes the system even more complex than it would be if, say, every car were driven by a robot.
We have all been caught in traffic jams that slow traffic to a crawl for a few or several miles, then suddenly dissipate without any sign of an accident or other obvious root cause. Well, that’s the butterfly effect. Scientists using computer models based on chaos theory have shown that even the slightest fluctuation in the system can lead to a cascade effect. (Actually, this description might be misleading. The computer models don’t exactly have “chaos elements.” Instead, they just achieve a decent level of accuracy in modelling, taking into account such variables as driver aggressiveness, intended top speed, and even vehicle performance. When there are enough variables in the model, the chaos just appears, inherently.)
Say, for example, a driver (for whatever reason) lets up on the throttle a bit, slowing their car slightly. The driver behind them might not notice right away, and will have to tap their brakes to match the slower speed. Then a third driver, seeing the brake lights, might hit the brakes for a little longer, just in case. Or if they’re aggressive, they might change lanes and cause another driver to slow down to avoid them. You can see where this is going. Often the little slowdowns like this will be absorbed into the flexibility of the system, but sometimes, especially in heavier traffic, the cascade will continue to snowball and a few minutes later, a few miles up the road, a complete logjam will appear.
The throttle-off driver, like the butterfly, is innocent and utterly oblivious to the havoc he has caused. The aggressive driver, however, that asshole who thinks he’s God in an SUV, who has to drive 80 during rush hour, who changes lanes without signalling and cuts off other drivers, is not innocent, merely ignorant. Even if he doesn’t cause that ultimate delay, the collision (I shan’t say “accident”), he’s deliberately introducing an extreme element of chaos into the system. That stop-and-go traffic you’re sitting in now might have been caused by some careless, leadfooted jerk that passed through here half an hour ago.
Imagine, though, a utopian world (and by “utopian” I mean “it’ll never happen”) where everyone maintained a reasonable speed, kept a safe distance between cars, signalled their intent before acting, and refrained from changing lanes without good reason. My contention is that the entire system would flow smoothly and with a minimum of collisions and slow-downs. Sure, no one would be able to do 80, but how amazing would it be to drive south on the Dan Ryan at 5:15 at a constant speed of 45?
