[sidewndr46]

It is plausibly a more efficient usage if both lanes of traffic are moving.

In practice drivers treat the "zipper merge" as acceptable when the left lane is closed ahead, there is 500 ft of road remaining and traffic in the right lane is already dead stopped. It isn't uncommon to see people approaching at 1.5x - 2x the posted speed limit and trying to "merge" then.

[Loudergood]

That is the correct behavior. If only one lane is stopped its far more likely to stretch back and block an exit that does not need to be blocked.