You do not want root on your self driving car.

Or to put it differently, I don't want to be driving on the same road as you with your rooted self driving car. You can be great sysadmin/coder, tesla guys may be too, but both of you changing random stuff without any communication with each other.. I've seen enough servers.

I am trying to imagine the typical arch Linux enthusiasts modifying the lane detection software on their cars and shudder at the thought.

This is a problem that will very quickly fix itself, as morbid as it sounds...

It's one thing to remove the warning stickers from a gas-fire oven, its another when you're commanding several thousand pounds of unintentional killing machine.

Keep your rooting to your phones.

All I want in a modern car is to have nothing smart in it that I'd _need_ (or, want) to root...

Everything to be completely open is really important, but I don't want you to have root or control over update if you are using your car on a public road.

Only certified (by the government) updates should be allowed on self driving cars. It should be at least a misdemeanor to have your own code on the car.

Do these things really matter unless you are going to verify the software yourself? (and if you are, kudos to you!)

While, in principle, users could organize their own communal verification programs for open software, that does not happen in practice, even when the software is widely used and needs to be safe (or at least secure - OpenSSL...)