Ah, Google does have an "idiot detector". I knew they'd need that. I was once thinking in terms of classifying other moving objects using RPG categories. A bike messenger is "chaotic good" - they may break rules but are trying to avoid collisions. Act predictably and let them avoid you. Drunks are "chaotic neutral" - expect random behavior, don't try to predict their movement, allow lots of extra clearance and leave room for evasive action. Cars or pedestrians trying to cut you off, harass you, or cause a collision are "chaotic evil" - take evasive action and leave area, or emergency stop.