[libria]

Part of the problem is a lack of established convention. When a theme park opens its gates in the morning, we expect a large crowd to jostle in through a constricted entrance like a funnel. However, when we queue up at the bank, if the line extends past the cordon, nobody runs up to that point and stands shoulder to shoulder with other patrons; we maintain a single file.

Which of these rules applies to cars merging? There isn't a set standard, so people invent their own and perceive their rule is universally understood.

[dvanduzer]

There is a protocol. Even in heavy traffic, if you observe the following distance that the DMV tells everyone to observe when taking a driving test there is always room to merge.

[jessaustin]

...following distance that the DMV tells everyone to observe...

Who on earth leaves such a distance in stop-and-go traffic? I certainly haven't seen it. You might as well just assume that every driver will be safe, considerate, and wise.

[danielweber]

If traffic is stop-and-go, a zipper merge is trivial.

[jessaustin]

Ummm, not in my experience.