It's not just motorcyclists who filter, either. Back in the late 1970s when I was an executive editor at Car and Driver, living and working in downtown Manhattan, I realized that everyone who used the roads or sidewalks there understood what I called "New York Rules." These rules were triggered by any traffic jam at any time. For example, where I lived, at the intersection of East 32nd Street and 3rd Avenue, I could see that every morning and afternoon, the lane-dividing stripes on 3rd Avenue would magically cease to mean anything. What might be four lanes turned into six, or however many cars, trucks, buses or other conveyances that could fit would fill every inch of space available between the sidewalks on the one-way street. It was entirely reasonable, and I never saw a cop bother to try to force people back into the official lanes.