| You are thinking about traffic in terms of cars per foot. The right way to think about it is in terms of cars passing a spot per second. A lot of traffic problems stem from the fact that you get more cars per second from quickly moving smooth traffic than from slowly moving dense traffic. Therefore if something bad happens to rapid smooth traffic, you quickly get a phase transition into horrible traffic. Now what does the transition from horrible traffic back to good traffic look like? The first step is that you have to get back to smooth traffic, and then that has to speed up. If nobody smooths out traffic deliberately, then you don't get this until the volume of people wanting to pass gets so light that all of the stop spots "evaporate" on their own because there is no pressure on them. Then the road speeds up. By contrast if traffic has been smoothed, the bottom speed steadily increases, and you get back to full speed much earlier. Plus smoothing traffic will save on your own car's wear and tear. Oh, and on merging? Go read http://ops.fhwa.dot.gov/wz/workshops/accessible/McCoy.htm. You will find that in the real world when drivers are instructed to merge late and politiely, merging happens significantly faster, with far fewer conflicts between drivers. So how you merge actually does matter. A lot. |