My daughter compares Boston drivers to a flock of swallows. You never see swallows collide, do you, despite the swirling, unpredictable nature of the flock? But if a starling flies through, havoc. We're all in our own flocks, used to the idiosyncratic idiocies that define our regional driving patterns. I've never touched another car in Boston, despite driving in rush hour traffic daily through the city center; but in Rome, London or Dallas, I'd be a starling.