[misterhtmlcss]

Probably drivers from the local transit union. I've seen/read about (union) activists doing some crazy things and it wouldn't surprise me that someone or some people would try to show with their life that this is a bad idea and therefore shouldn't replace a human driven system.

[elygre]

Do you have any data to back the assertion that this was about unions?

My gut says that it’s more probable that it was the hacker news crowd trying to test the technology, but I have to admit to have absolutely no data to support this assertion, either.

[dagw]

I'm almost certain you are right, especially considering this bus operated in an area where there a lot of tech companies.