> The people driving at a constant speed are not the problem. They keep traffic flowing smoothly, even if it is slightly below the speed limit. No, they don't.

> The people driving at a constant speed are not the problem. They keep traffic flowing smoothly, even if it is slightly below the speed limit. No, they don't. They create pile-ups behind them when driving unreasonably slow. I see it every day. Dozens of cars stuck behind slow drivers and huge empty gaps of road in front of them. The only way they would keep traffic flowing smoothly is if they did not drive slower than the surrounding traffic. > The ones who create the problem are those changing lanes to gain 5 mph and get to their destination one minute sooner. I think you might be ascribing causation where it doesn't exist. Most of the cars I see zig-zagging through traffic (which is futile given the problems I highlighted) do so because of the aforementioned slow drivers who unreasonably plug-up the road. People get impatient and the zig-zag game starts. I see this effect every day. Leaving the valley the road slopes up. You are climbing. Early in the morning traffic is relatively light. People are moving at, say 75 mph. And then it happens. A few cars have drivers who, for some reason, do not maintain speed while climbing, they slow down to 65, even 60 going up the hill. The cars are perfectly capable of maintaining speed, it's the driver who does not. When this takes place the effect is nearly instantaneous. Cars pile-up behind the slow-climbing cars and a few of them start zig-zagging to get around them. It's a mess. And with more traffic it launches a wave that ripples backwards and starts what eventually becomes a big problem as more people pile onto the highway. The cause in this case isn't people who want to drive too fast, the root cause is drivers who do not maintain speed during a climb. > If people would just pick a lane and a speed and stick to it the overall throughput of the road would be much improved. I completely agree with one modification: Speeds need to be layered. There are people who want to drive unusually slow. There are trucks and buses that drive at 50 mph. They should not be allowed to get over to the left, pick that lane and stick to it. That's the problem I am referring to. We don't have any rules that prevent someone doing 60 mph from inserting themselves into traffic flowing nicely at 70 or 75. They come into that flow and it's like a rock in an otherwise laminar flow stream, they create turbulence. It's not about going fast, it's about extracting better efficiency out of the road. I don't have a problem with folks who want to driver slower. Good for them. Just get out of the way and let the rest of the traffic flow nicely.