In real life, I observe both, often simultaneously. The far left or right lane can back up a very long way as everybody tries for the same turn. Oblivious or selfish people bypass it all and try to change lanes at the last second, often with sudden braking and occasional bent metal because the target lane is full and stopped.

>Oblivious or selfish

It's not selfish to use the road to its full potential. We should all be merging at the last moment, and using zipper merging to allow smooth traffic flow.

Zipper merging is good when a lane ends, but that's not what I'm talking about. Attempting a zipper merge into a turn lane at the last moment is a really bad idea, because by attempting to do so you will block a travel lane that other people will want to use for going straight. This slows them down at best, and causes crashes if you're unlucky.

Merge at the last moment when your lane ends. Do not merge at the last moment when you need to get into a turn lane. These are different scenarios.

I expect that the naive traffic sim implementation is to simulate everyone following their GPS perfectly. Real humans seem to have a bit more randomness and a mix of different driving patterns.

I wonder how regular GPS use has changed real-world traffic patterns?