It's not hard to find videos of self-driving Teslas wilding in bus lanes. Check the videos out, then consider:

"There was an interesting side-note in Tesla’s last earnings call, where they explained the main challenge of releasing Full-Self Driving (supervised!) in China was a quirk of Chinese roads: the bus-only lanes.

Well, jeez, we have bus-only lanes here in Chicago, too. Like many other American metropolises… including Austin TX, where Tesla plans to rollout unsupervised autonomous vehicles in a matter of weeks..."

It's one of those regional differences to driving that make a generalizable self-driving platform an exceedingly tough technical nut to crack... unless you're willing to just plain ignore the local rules.