I saw the same thing in Boston. Instead of "violating the rules", I would say that local drivers obey a set of unwritten local rules that are more appropriate for the situations they encounter. These local rules make things safer and more efficient because the global rules that are written for wide, straight highways don't map well onto low visibility corners, confusing or incorrect signage, low speed side roads merging onto fast thoroughfares, roads (sometimes purposely) without painted lines, etc. I felt that Boston drivers often adopted Right of Way, a notion familiar to boaters. Faster cars with more maneuverability are in general expected to avoid slower cars or those with less maneuverability. If someone pulls out in front of you (perhaps because they were stopped and couldn't find a better time to merge), it's your duty to not hit them. On the other hand, if you are on a side street waiting to merge, it's expected that you wait for a break that's "big enough", then pull out and accelerate as fast as possible. None of these rules are written, but they are still consistent and safer than trying to rigidly apply global rules to the situation.