The latest leading-edge thinking in traffic-calming is that we should remove traffic controls, not add them. Passive controls, that is, like signage; active controls, hard controls, like traffic circles (rotaries, roundabouts), merge lanes -- those can stay. But Yield signs at the traffic circle entrance, "lane ending" indicators, even curbs, stop signs and traffic lights: Those should go.
The thinking is that without them, we think more. With them, we give over our control over our fates to the signage. At the same time, we can do things that, superficially, make a road more dangerous: We allow parking where we'd previously barred it; we make the road-beds narrower instead of wider; we remove turn lanes and traffic lights; we remove explicit barriers between people and traffic. (Note that this doesn't mean eliminating sidewalks altogether: "Instead of a raised curb, sidewalks are denoted by texture and color.")
Results are counter-intuitive: Traffic moves more slowly, and yet trip times are reduced. It's the kind of result that a simplistic understanding of systems can't predict, but that an ecological understanding can.
I have to admit that I was resistent to the idea when I first read it. It reminded me of a trip to Seattle in February of 2000, when I noted the conspicuous absence of stop signs at intersections in many residential neighborhoods. But as I reflect on it, it strikes me that, at the least, bad signage really is worse than no signage. Signage, after all, plays to our conscious, rational mind, which is easily stymied by contradiction and inconsistency in ways that our sub-conscious, a-rational mind is not. And I recall that, when I approached those intersections, I stopped and looked very carefully. I paid attention to what I was doing (driving) instead of to other things.
As I think through it further, I find myself thinking of least three other ideas: The human factors design concept of affordance; Jane Jacobs's "eyes on the street"; and the zen/taoist/buddhist tightrope of mindfulness:mindlessness. The common thread is that they all tap into aspects of humanity that are essentially sub-conscious, in the sense of being as tied to our animal nature as to our human nature. They are rational in the sense that sense can be made of them; they are also a-rational, in the sense that we seldom bother to try. (And also in the sense that when we do bother to try, we often screw it up.) Most imporatantly, they are ecological, not based on a simplistic, modernist understanding of systems theory.
We still need to be able to inculcate awareness of self-interest at a low level of consciousness. We can only rely on our natural accident-avoidance to carry us so far, especially with as many distractions as the world affords.