This is the AIRBUS SYNDROME that has been talked about for years, finally happening - electronic control with no mechanical connections between the pilot/driver (in this case) and the engine or flight controls...
Do a Google on A330 or Airfrance and Airbus crashes...
Look, our computer programs freeze/crash/go-nuts on a regular basis and we are all familiar with this.. A dedicated CPU controller, like what is in your washing machine, DVD player, etc. is vastly more reliable than Billy Gates operating systems, but that does not mean it is perfect... If you have a system that has a MTBF of 10 million hours - meaning it will operate on average 10,000,000 hours before failing once, that is pretty good.. But if you have a million of these machines operating, then every ten hours one will fail... This is what is statistically happening to Toyota (and other car companies will not be far behind)