[Doxin]

Those don't go terribly fast, In addition to the tiny tiny wheels not having a lot of grip leading to slow acceleration and deceleration. Getting those to align with the track is an operation that you'll only want to be doing at standstill.

[newnewpdro]

They aren't the drive wheels so they have no impact on acceleration, the rubber tires are still used for traction.

Alignment could be easily automated today, or a low-tech mechanical guide mechanism could be added for the bus.

I'd expect the maximum comfortable speed to be substantially higher than the guide wheel approach. That guide wheel design seems better suited for aligning the rail wheels than continuous operation.