This orange bus has blue/white/yellow/black Y2K decoration and front/rear light details.  Clear windows reveal a black interior, and the bare metal base rolls on 5 blade wheels.

This was part of the .COM series.  It appeared in multiple waves with the alternate 5 spoke version.  There are also a bunch of color variants.  I don’t know the details of which colors/wheels connect to the various series numbers and/or exclusive releases.