I hate traffic, you hate traffic, we all hate traffic, but we can’t do anything about it because we are traffic. The conventional wisdom, at least, my conventional wisdom on any of my local freeways, is to get out of it by driving as fast as possible, and perhaps that slow drivers should be charged with crimes against humanity. (Yeah, guess where I grew up…) Well, instead of getting mad about it, what if we asked why traffic jams happen? William Beatty applies fluid mechanics to traffic flow, and comes up with some surprising results: Drive at an even speed, maintain at least two car lengths between you and the car ahead of you, and don’t punish people by merging. When he tried this out.
Once upon a time, years ago, I was driving through a number of stop/go traffic waves on I-520 at rush hour in Seattle. I decided to try something. On a day when I immediately started hitting the usual “waves” of stopped traffic, I decided to drive slow. Rather than repeatedly rushing ahead with everyone else, only to come to a halt, I decided to try to drive at the average speed of the traffic. I let a huge gap open up ahead of me, and timed things so I was arriving at the next “stop-wave” just as the last red brake lights were turning off ahead of me. It certainly felt weird to have that huge empty space ahead of me, but I knew I was driving no slower than anyone else. Sometimes I hit it just right and never had to touch the brakes at all, but sometimes I was too fast or slow. There were many “waves” that evening, and this gave me many opportunities to improve my skill as I drove along.
I kept this up for maybe half an hour while approaching the city. Finally I happened to glance at my rearview mirror. There was an interesting sight.
It was dusk, the headlights were on, and I was going down a long hill to the bridges. I had a view of miles of highway behind me. In the other lane I could see maybe five of the traffic stop-waves. But in the lane behind me, for miles, TOTALLY UNIFORM DISTRIBUTION. I hadn’t realized it, but by driving at the average speed, my car had been “eating” traffic waves. Everyone ahead of me was caught in the stop/go cycle, while everyone behind me was forced to go at a nice smooth 35MPH or so. My single tiny car had erased miles and miles of stop-and-go traffic. Just one single “lubricant atom” had a profound effect on the turbulent particle flow within the “tube.”
Wow! Now, this is the kind of experiment I’ll have to repeat next time I’m stuck in rush-hour traffic.