Probably far from a new thought, but as I was riding in this morning I was wondering why it was taking the drivers around me so long to make decisions and act on them... and why so few of them seemed to be aware I was there, if I got there quickly. There are all the usual explanations of carelessness and so on, but I think something that really contributes (and does for pedestrians too) is that the level of alertness that is required of us, and which we get used to operating at, on the bike is just not required of drivers. I know that, even if it's been a bit of a dozy day, once I'm on the bike I'm reacting faster, seeing more, thinking more, much more alert, and the world around me almost seems to slow because I'm working at a faster processing speed. In the car, that doesn't happen - at least, not to the same extent, and not unless I decide to get a bit frisky. Under normal commuting conditions, the level of psychological and physiological arousal is just much lower.