[SR2Z]

The real problem is that Waymo has to drive the speed limit.

Human drivers move left if they're gonna be on the highway for a while so that they don't have to keep braking and accelerating for merging traffic.

They will speed a little bit if they have to, which means that it's common for all but the right lane to not be OK for a Waymo going the speed limit. Obviously this then leads to a subpar ride.