I think society will eventually demand it, all it will take is a few fatalities, and even if society doesn't, I can't help but think that some company will win out _because_ they are open, like Red Hat.
Society cares about working products, not the tech behind it - I don't see calls specifically for making critical software open source any time sooner than the year of the Linux desktop.
Regulations and fines are proven tools, and even if it doesn't make autonomous cars significantly safer, it will make them expensive enough to reduce fatalities.
Regulations and fines are proven tools, and even if it doesn't make autonomous cars significantly safer, it will make them expensive enough to reduce fatalities.