[Dylan16807]

The thing that blocks up traffic at a merge is when people can't get over smoothly.

If everyone gets over at the first opportunity, then things go fine. The empty lane isn't wasted, it absorbs brief bursts in traffic that need more time to get over. But even if it was wasted, that wouldn't be a big deal. A 5-mile long section with fewer lanes and a 5.5-mile long section with fewer lanes will have almost the same throughput.

Everyone staying split across two lanes until the end and aligning themselves to do a clean zipper merge also goes fine.

What makes everything go wrong is when people drive down the nice empty lane that's ending and intend to do a normal merge at the end, but they don't start it early enough. Then everything slows down as they squeeze over.

[plaidfuji]

In my experience what causes the slowdown are the people who merged too early who then resentfully close the gap in front of them when people try to merge later than them, simultaneously increasing the likelihood that they’ll rear end the car in front of them and making it harder for the people trying to merge properly to do so.

[dazc]

'...when people try to merge later than them,'

You mean the people who must get past every single car and merge at the last possible second?

[level1ten]

Just use the lane normally and zipper merge when the lane ends. Don't waste space. Don't block people. You don't get brownie points for being in the "correct" lane as soon as possible, and it doesn't help to police others who are using the existing lane. It really isn't that hard.

[nytesky]

A zipper merge is fine, both lanes tend to fill up.

What I often see if a lane that intended to go through and a turning lane that is backed up; people pretend to be on through lane, then stop to merge at last minute into long turning lane and void the line.

[Dylan16807]

Doesn't that just move the gap slightly? If anything, a tight squeeze should mean the gap behind them is even bigger than the gap that existed before.