Very good point. A fascinating study in driver behaviour is to go to a high point where you can observe a congested freeway. The Getty Centre above the 405 Fr

Very good point. A fascinating study in driver behaviour is to go to a high point where you can observe a congested freeway. The Getty Centre above the 405 Freeway in Los Angeles is an excellent example. The way I would describe it is watching fast-flowing water. Then block it with a piece of wood, and lift it again, then watch the wave pattern flow down the water. That's exactly what traffic looks like from above. A couple of slow moving cars, someone doing a stupid lane move, and everyone touches the brakes. This ripples down the flow until, much further down the road, people are all stopped and they have no idea why. Every road, for a given level of traffic, has an optimum speed that the traffic will flow the best. If robotic control could read that value, and stick to it, you would see Freeways flowing much better. However, that's all a long way off. I'd settle for widespread fitting of adaptive cruise control and getting people to actually use it.