Kauai does not have a lot of roads, but those that exist are heavily used. It is common to experience traffic jams that may stretch for miles. The one-lane bridges contribute to the backups. Lots of cars, one-line bridges, and no signals of any kind. You are pretty much on your own.
Getting across one-road bridges under such conditions depends on a convention - let a few cars go and then it is your turn. The number is not clearly specified, but somehow it seems to work. The one thing you don't want to do is hesitate. A break in the action and it automatically becomes the other side's turn. Once in a while, someone will join the end of the line late even though there is a break and follow anyway. This is clearly a violation of protocol. There is very little honking when this happens. Throwing up a "shaka" is kind of an apology, but should not be overused.