As I wrote before, it will be a long time before self-driving vehicles are to the point where they can be trusted in all driving condition. However, the regulators of California have "opened a pathway for the public to get self-driving cars of the future that lack a steering wheel or pedals."
This is world-class incompetent.
Self-driving vehicles must retain three mechanisms -- steering wheel, brakes, and power-off switch -- to allow a human to override the system in case of failure. This is not to say that humans will often use this capability, as most of the time they will be napping, playing games, watching video, or texting, and will not be in the right frame of mind to make last-minute decisions. However, the option must always be available in case something breaks.
The option to override the vehicle must be present in case of hacking because, by definition, the vehicle will always be connected to the Internet and therefore susceptible to malware. It is not possible to guarantee that a vehicle has impregnable defenses against malware, so humans must always be able to take manual control.
To avoid accidental use of the override, there needs to be a switch which must first be activated, with this switch being unlikely to be activated in day-to-day operations. It would be completely unacceptable to require the use of a key, password, or fingerprint because if the switch is needed, it would be needed immediately. Something as simple as a switch with a cover which hinges out of the way would suffice.
The other states should pass legislation to mandate the above to prevent being californicated via the Full Faith and Credit Clause of the U.S. Constitution.